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BrowseInterestsStay InformedCareerPersonal GrowthFiction & BiographiesHealth & FitnessLifestyleCultureBrowse byBooksAudiobooksNews & MagazinesSheet MusicBrowse allUploadSign inJoin﻿UNITED NATIONSE • Economic and Social Council Distr. GENERAL ECE/ENERGYIl9 3 February 1992 Original: ENGLISH .---------------------------------------------------- ec.ONOMJC COMMISSION FOR EUROPE COMMITTEE ON ENERGY WORKING PARTY ON COAL CODE OF UNIFORM STANDARDS AND PROCEDURES FOR THE PERFORMANCE OF DRAUGHT SURVEYS OF COAL CARGOES GE.92-30190/4244B j . ECE/ENERGY/19 page iii PREFACE Under the auspices of the ECE Working Party on Coal. this Code of Uniform Standards and Procedures for the Performance of Draught Surveys of Coal Cargoes has been elaborated by experts from major coal exporting and importing countries and was completed in October 1991. The Code was adopted by the ECE Working Party on Coal at its session in October 1991 (ENERGY/WP.1/2. para. 42) and endorsed by the ECE Committee on Energy at its session in November 1991 (ECE/ENERGY/IS, para. 23 (e». The maintenance and application of the Code will be monitored by the ECE Meeting of Experts on Coal Trade, Statistics and Transport. in cooperation with other interested international organizations. NOTE: Mention of any names of commercial firms in this document is only for reference to a process and does not imply endorsement by the United Nations. ECE/ENERGY/19 page iv BACKGROUND Draught survey is one of the most common methods in use worldwide for determining the weight of seaborne bulk cargoes of low unit value, and the most common method for bulk coal cargoes transported by sea. In 1990, bulk cargoes transported by sea amounted to almost 1 billion tonnes, of which one third was accounted for by coal. The accuracy of draught surveys may vary for several reasons. Discrepancies in draught survey results between the points of loading and unloading may give rise- to commercial disputes between the sellers, vessel operators, buyers and surveyors, over which weight to accept as the basis for payment of the cargo, freight, port fees and other charges. With the volume and value of future seaborne coal trade expected to increase, shippers and receivers have become more and more concerned about discrepancies in draught survey results and consequently the need for a remedy arose. The Working Party on Coal, a subsidiary body of the United Nations Economic Commission for Europe, agreed in 1989 to make proposals for an improvement of the situation. The use throughout the world of uniform standards and procedures for the performance of draught surveys was suggested for enhancing their accuracy. The resulting Code of Uniform Standards and Procedures for the Performance of Draught Surveys of Coal Cargoes represents a set of recommendations which may be applied in full or in part by parties in international coal trade who see fit to do so. Wide application of the Code is expected to benefit all the parties involved and to contribute to an improvement of international coal trade practices. ECE/ENERGY/19 page v INTRODUCTION For over a century, draught surveys have been accepted as an accurate and convenient means of establishing the weight of bulk cargoes. They have been the basis for the preparation of bills of lading and assessing various charges and port fees. The basic principle upon which the draught survey methodology is based is over 2,200 years old tracing back to Archimedes' law of buoyancy. The application of this law of physics to ships was further refined by formulas developed by European naval architects in the nineteenth century. While this principle is the basis for the work of draught surveyors throughout the world, the procedures by which they are applied vary considerably from country to country and even from port to port. The purpose of this Code is to make these procedures reasonably uniform. It is further designed to provide a professional standard for the work of the draught surveyor. As the Code is also intended for the benefit of persons who may not have seafaring experience, certain aspects are explained in greater detail than might be considered necessary by master mariners. A glossary of terms has been added under Part 5. Additionally, this Code is intended to provide a source of information and serve as a reference book for those who make use of draught survey reports or equivalent weight certificates in the routine accomplishment of their commercial pursuits. It should be emphasized that in draught surveying there is no substitute for experience and that accuracy often depends on careful attention to details and proper and diligent handling of unusual circumstances which may arise from time to time. It is hoped that neophyte and practising draught surveyors along with all other persons who are involved with the commerce of bulk cargoes, will find this document to be of value. It is anticipated that in the years to come methods will be refined and new equipment will be developed which will improve the draught survey methodology. Therefore it is intended to revise the Code from time to time so as to keep abreast of such advances. Following this trend, there is further a need for: including in a vessel's design special features and apparatus intended to facilitate and refine draught readings and tank soundings; improving the accuracy and standardizing the content and format of the ship's technical data especially in the area of tank calibration; providing each vessel with a "Data Manual for Draught Surveys" which is certified by the vessel's home administration or its classification society; improving surveyors' equipment and devising new equipment taking advantage of advances in technology; ECE/ENERGY/19 page vi where necessary, providing a means for continuing education to improve the skills of draught surveyors; studying the content of and means for developing an international database on draught surveys which could be used to establish norms and identify specific problems which need to be addressed; promoting an international forum for periodic dialogue between all parties who have an interest in draught surveys. Maybe this Code and its widespread use will lead to international cooperative programmes for improvements also in these areas. Preface ECE/ENERGY/19 page vii TABLE OF CONTENTS iii ..................................................... ,. . iv Background . Introduc~ion . Table of Contents v vii ............................................................................................ PART 1. praught survey procedures ..••••••••••..•••.••.•••.•••••• 1 UNIECE Draught Survey Code: Section A: principles Section B: Form "A" Form "B" Form "c" Form "D/1" 3 4 5 6 7 8 9 ................... Form "D/2" Form "D/3" Form liE" Introduction to draught survey and general ...................................................................................... 10 1. 2. 3. The principle of Archimedes ••.•••••••••••••. Variation of displacement of a loaded ship ship are actually partly loaded with 10 10 "Empty" ballast .......................................... 11 11 12 4. 5. 6. Relevance of draught surveys Loading of multiple cargoes Requirement for draught surveys during loading or unloading Monitoring of discrepancies and trends Controls before draught survey starts and time allocation 14 .. .. ...................................... . . 12 13 7. 8. Utilization of the UNIEeE Draught Survey Code 15 Forms "A" through "E" ••••••••••••••••••••••••••••••••••••••• 15 1. 2. 3. 4. Format and procedure ••••••• • •••••••••••••••• Vessel acceptance ••••••••••••••••• Accuracy .. * • • • • • • • • • • • • • • ••••••••••••••• Instructions for completing Forms "A" through tiE" of the UNIEeE Draught Survey Code ••••••••••••••••• 16 15 IS 16 16 Form ·'A'· Preface page ••...........................•........• ~ 18 Form "B" •••••••••••••••••••••••••••••••••••••• Calculation of constant Constant certificate 19 20 ECE/ENERGY/19 page viii Form "c" TABLE OF CONTENTS (continued) .............................................................. Readinq the drauqhts •..•.••••••••••••.•••••••.••.•.•••• Correction of draughts from marks to perpendiculars .Calculation of hog or sag •••••••••••••••••••••••••••••• Calculation of M/M/M draught ••••••••••••••••••••••••••• Calculation of trim ••.•••••••••••••••••.•••••••••.••••• Determination of displacement (1) •••••••••••••••••••••• Calculation of displacement (2) •••••••••••••••••••••••• trim correction ••••••••••••••.•.•••••••• density correction •••••••••••••••••••••• displacement (3) •••••••••••••••••••••• total deductibles ••••••••••••••••••••• final corrected displacement •••••••••• Calculation of Calculation of Calculation of Calculation of Calculation of Form "OIl" ..................................................................... Ballast tanks Bilges . Duct keels and swimming pools •••••••••••••••• Fresh water . Form "0/2" Form "0/3" ............................................................. .................................................. Summary of deductibles Form "E" ................................. Calculation of cargo weight ••••••••••••••••• Section C: 1. 2. 3. 4. S. 6. 1. 8. 9. 10. Factors affecting draught surveys Incorrect hydrostatic information or draught marks Incorrect tank calibrations ••••••••••••••••••••••• Mud andlor scale in ballast tanks ••••••••••••••••• Bottom shell growth ........••..................... Water disturbance ................................. Variations in sea water density •••••••••••• Vessel squat . Asymmetrical hull deflections . . So lar bendinq ........•....•....................•.. Use of approximate methods for corrections . . 20 21 21 22 22 25 25 26 26 27 28 28 29 29 30 30 31 31 31 32 33 33 34 35 35 35 3S 36 36 36 36 36 31 37 Section D: ECE/ENERGY/19 page ix TABLE OF CONTENTS (continued) Improving accuracy " .. A. The Buyers, the Sellers. the Charterers. the Terminals and the Vessel's Staff •••••••••••••••••• Telex format to advise Master of draught survey ••• Clause in charter party on draught survey ••••••••• The Stevedores and the Terminals •••••••••••••••••• The Insurance Companies ••••••••••••••••••••••••••• The Administrations .. The Cons tant .. B. C. D. E. F. G. PART 2. Draught survey instruments •••••••••••••••••••••••••••••• Remarks on draught survey instruments ••••••••••••••••••••••• Equipment for the conduct of draught surveys •••••.•••••••••• II. III. IV. VI. VII. VIII. IX. XI. XII. XIII. 1. Reading freeboards/draughts - rough seas Draught indicator pattern ••••••••••••••••••••.•••• Device for ship's "free-board" measurements ••.•... Water sampling devices .. .. Proving side tanks are full .. Linear distance measuring devices ••••••••••.•••.•• Steel tape measure Tank sounding tape ................................................................ V. Density measuring device •••.••••••••••••.••••••••• Draught survey hydrometer ••••••••••••••••••••••••• Glass/plexiglass tube ••••••••••••••••••••••••••••• Dens i ty s8Jnples pump ., .. Water sensitive paste ••••••••••••••••••••••••••••• Enqineers scale .. X. Calculator . Powerful torch .................................... Binoculars ..................... ., . Conversion factors . 38 38 38 39 41 41 41 41 43 44 44 4S 46 50 S3 S4 55 55 55 56 57 60 60 60 60 60 60 60 60 ECE/ENERGY 119 page x PART 3. CONTENTS (continued) Vessel (locUITlents .. General principles .••.••••••••••.•••••••••••••••••••..•••... PART 4. 4. 5. 6. 7. 8. 9. 10. 11. 1. 2. 3. Unification of the Vessel information The basic document for the performance of list of documents •••••••••••••• . . drauqht survey .. Provisions for sounding tanks ••••••••••••••••••••• Verification of ballast tank condition •••••••••••• Light ship weiqht .. Particulars of vessel ••••••••••••••••••••••••••••• The required hydrostatic data ••••••••.•••••••••••• Displacement .. Summary of the required documents ••••••••••.•••••• Final observations •••••••••••••••••••••••••••••••• Surveyors' qualifications PART 5. Annex A General problems . Specific considerations and limitations Glossary of terms and definitions ••••.••••..••.••.•••.•. Automatic calculation program connected with the draught survey . Annex B - Bibliography and References •••••••••••••••••••••••••••• 61 62 62 63 63 64 65 65 66 66 67 67 67 69 70 71 75 109 121 ECE/C:~;::Rr:;!' /19 pa€E 1 PART 1. A DRAUGHT SURVEY ,............_...........__., ~~--~~ PROCEDURES '----,~, --' ECE/ENERGY/19 page 2 UN/ECE CODE OF UNIFORM STANDARDS AND PROCEDURES FOR THE PERFORMANCE OF DRAUGHT SURVEYS OF COAL CARGOES PART 1 - DRAUGHT SURVEY PROCEDURES The following Code of procedures is recommended for calculating the weight of dry cargoes at both loading and discharge porta. Provided that approved suitable vessel information is available, that is the vessel's draught survey manual issued upon request of the shipowners by the classification societies, and also provided that the work is conducted by qualified and experienced surveyors, the adoption of this code will ensure that cargo weights will be consistently determiped within an accuracy of 0.5', which has been accepted by bulk trades throughout the world. In fact, checks conducted in various parts of the world, where the same vessel has been surveyed by independent operators, indicate that an order of accuracy to within 0.1' can be obtained under proper and favourable conditions. For each draught survey the Surveyor must provide his client with a draught survey report which is equivalent to a weight certificate. This document should indicate the way in which the survey was conducted, the calculations which were performed, and any other information pertinent to the survey, including problems which may have been encountered. The UNIEeE Draught Survey Code Forms "A", "B", "C", ItD/1", "0/2", "0/3" and "E", constitute the formats for such a report. These forms serve the purpose of: achieving uniformity in the format and content of draught survey reports; facilitating the auditing of the reports; accomodating the range of instruments used for the preparation of reports which varies from pencils to computers; furnishing complete data which may be utilized in data bases useful to commercial and professional interests. Section A of Part 1 provides an introduction to the draught survey including some general principles. Section B contains a line by line description of the proper utilization of the Forms. Section C summarizes some of the factors which can affect draught surveys. Section D gives advice on improving the accuracy. ECE/::r;;::~:;Y /l~ page 3 U.N. • ECE • DRAUGHT SURVEY CODE 001 I 002 ORAUGHTSUAVEY REPORT OF CARGO IN BULK RLCAOED FORM "A" I I 003 UNLOAOEJ I 004 Corporale Ident'licauon: , 005 006 OH.ee 01 the surveyor at: I 007 008 Telepnone no: Fax no: Te.ex no, t 009 I 010 Vessel MIV: Calliene's: Survey 110: I 011 I 012 Vessel prevIous name-s: Reglslry: I 013 i 014 Built year: By' Fiag: I 015 I , 016 Survey requested by: I 017 On the account of: 018 Attended also by: 019 020 021 aSOjcint survevor numoirellr.-c~:tcr:nc I 022 I I 023 This is to certify that the undersigned did. in Bona Fide. attend on board the subject vessel as she iay a;:oa! I 024 at the port of: for the purpose ot ce!ermlning by craugnt ccmcutarcr.s :::02 025 amount of 026 loaded. unloaced (notes no, ) ana haVing touoweo the rules as set :'1 ::-:e 027 U.N. I ECE Q::xje of Urifo:cnStandarcs and Procedures for the Performance of Draught Surveys ha',€: :~.e 028 following to report: 029 030 STARTING SURVEY FINISHING SURVE';' ! 031 Attending the surveys: date: dale: 032 hours: from: to: hours: trorn: to: 033 Name of surveyoris 034 Master I 035 036 Chief Otticer 037 Chief Engineer 038 Witness draughts I 039 J 040 Witness tank sounding 041 042 Ship's location 043 Weather temperature 044 045 Sea condition 046 Heading of Ship 047 048 Direction wind 049 Stream speed Km Ih 050 Tide 051 Ice 052 053 054 Cargo handling eaulpment T, Crouglll on txlard: 055 056 Missmg snlp's eQUipment: 057 Ed. October 15, 1991 - 1.8 - MIcrosoft Excel 2.2 1 • 7 ECE/ENERGY/-!9 page 4 U.N. • ECE • DRAUGHT SURVEY CODE 058 059 DRAUGHT SURVEY. REPORT OF CARGO IN SULK BLOADED FORM "S" 060 UNLOADED 061 Corpor •• idenulication: 062 063 Vessel MN: Survey no: 064 065 General remarks by the surveyorls 066 ,-- . 067 Correction for stem and stern obtained by: calculation ~'.bl.S 068 Correction for trim (1) obtained by: = calculation tables 069 Correction for trim (2) obtained by: calculation tables 070 Correction due to trim for liquid applied at: ..._ soundings volumes 071 Correction due to trim for liquid obtained by: ,__ calculation tables 072 ,__ 073 Ship's approved hydrostatic tables and lightship information issued by and dated: 074 075 076 077 078 079 080 Degree of tank calibration complies with code: DYes ONo 081 082 Range 0' trim c:crredion tables available: 083 084 Shipyard no.: Hull no .. Dated at: C85 086 Surveyor remarlls on sh~'s documents: 087 088 meters metric tonnes 089 Length overall Constant declared 090 Length between p.p, Constant calculated 091 Extreme breadth Light displacement 092 Moulded breadth light shipweight (plan) 093 Depth overall incl. keel plate Summer displacement 094 Moulded depth Summer deadweight 095 Summer draught Net register Ions 096 Summer freeboard Gross register Tons 097 098 STARTING SURVEY FINISHING SURVEY 099 Tonnes per Centimetre Immersion 100 Longitudinal Centre of Flotation 101 Distance marks forward pp. (forward· aft-) 102 Distance marks atter pp. (forward· afl+) 103 Distance marks midship pp. (forward. aft+) 104 Moment to Trim One Centimetre +50 105 Momenl to Trim One Centimetre ·50 106 Vessel list 107 Accessibility of sounding pipes 108 Working order of gauges 109 Legibility of draught marks 110 111 112 113 114 115 This form should be filled With pertinent ShIpyard-registry data by Ihe Master in advance of survey start to 116 reduce lime/inconvenience. Ed. October 15, 1991·1.8· Microsoft Excel 2.2 2·7 .: U.N. • ECE • DRAUGHT SURVEY CODe ECEl::~:::?C;'i, .L ' page 5 117 118 DRAUGHT SURVEY REPORT OF CARGO IN BULK RLOADED FORM "C" , 19 UNLOADED 120 Corporale idemilicalion: 121 122 VesselMN: . SOl"Vey no' 123 124 DRAUGHT STATEMENT 125 126 DRAUGHT READINGS HOURS: STARTING SURVEY FINISHING SURVE'( 127 FROM: TO: FROM: TO 128 meters meters '29 Draught forward port 130 Draught forward starboard 131 Draught forward mean 132 133 Stem correction 134 Draught forward (corrected to rare .pp.) 135 136 Draught after porI 137 Draught after starboard 138 Draught after mean 139 140 Stem correction 141 Draught after (corrected to after pp.) 142 143 Draught fore & after mean 144 145 Draught midship port 146 Draught midship starboard 147 Draught midship mean 148 Midship correction 149 Draught midship (corrected to midship pp.) 150 Sag (+J Hog (-) 151 Mean of means 152 Draught extreme corrected for hog/sag 153 Correction (.) for keel tickness if applicable 154 Draught moulded corrected for hog/sag (Note: Utilize line 152 or line 154) 155 Trim: fwd (.) aft (+) 156 Kg/m3 Kg/m3 157 Observed density I I I I 158 (Ship's tables density Kg/m3 ) 159 (Hydrometer no. ) 160 Metnc tonnes Nietrlc tonnes 161 Displacement (at Kg/m3 density) 162 First trim correction 163 Second trim correction 164 Total trim correction 165 166 Displacement corrected for trim 167 Correction for density average 168 Displacement corrected for density 169 Total deductibles 170 Displacement corrected for deduclibles 171 172 173 174 Draughts. densjties. fresh water and ballast soundings witnessed and agreed to by the Chief Ofltcer. Fuel oil 175 soundings witnessed and agreed to by the Chief Engineer unless otherwise stated in form -A- 176 177 Ed. October 15. 1991 ·1.8· Microsoft Excel 2.2 3-7 ECE/ENERGY/19 page 6 U.N. • ECE • DRAUGHT SURVEY CODE 178 179 DRAUGHT SURVEY REPORT OF CARGO IN BULK BLOADEO FORM "01" 180 UNLOADED 181 CO~(IIII. idenllfH:adon: 182 183 V .. e4MN: SUI1Iey no: 184 185 STARTING SOUNDING' From HoUts: To Hours: Oale: Trim: 186 187 188 Compartment Tide: Maximum Soundlng SoundIng Volume Densltyof Total 189 • Tank no. height I ullage I ullage corrected water weight 190 • Bilges measured n corrected for lor trim I list In air Metric 191 • Ouel keel meters melers trIm I list m3 Kglm3 lonnes 192 melers 193 A· BALLAST 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 Totat A 220 221 B • FRESH WATER 222 223 224 225 226 227 228 229 230 231 232 Total B 233 234 ('j Sialemeni 01 obSlrudions in sounding lube'S: . 235 Ed. October T 5, 1991 . 1.8 . Microsoft Excel 2.2 4·7 U.N. • ECE • DRAUGHT SURVEY CODe 235 236 DRAUGHT SURVEY REPORT OF CARGO IN BULK RLOADED FOAM "02" 237 UNLOADED 238 COtpOf". idenllfication: 239 240 Vea. ""'IV: Surv • .,. F'1O 241 242 FINISHING SOUNOING. F,om Hours To Hou's Oa'. Trim 243 244 245 Compartment TIUe: Maximum Sounding Sounding Volume Density of r,..,t,",,' ,",,,,,. 246 • Tank no. height / ullage I ullage corrected water we\;~.: 247 • Bilges measured n corrected for for trim I list in air Me!';c 248. • Duct keel meters meters trim IlIsl m3 Kgtm3 tcr:~'!-<; 249 meters 250 A· BALLAST 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 TolalA 277 278 B·FRESH WATER 279 280 281 282 283 284 285 286 287 288 289 290 Total B 291 292 r) Sialemenl gI obsll'UCiions in sounding lubtl{s: 293 . Ed. October 15. 1991 . 1.8· Microsoft Excel 2.2 5 7 ECE/ENERGY/19 page 8 U.N. • ECE • DRAUGHT SURVEY CODe 304 305 DRAUGHT SURVEY REPORT OF CARGO IN BULK R~OADED . FORM "03" 306 UNLOADED 307 COf'PO".e ldemificallon: 308 309 v ..... wv: Survey no: 310 311 SOUNDINGS 312 313 I STARTING SURVEY FINISHING SURVEY 314 ~mpartment 315 nUe: Total Sounding Actual Actual Weight Sounding Actual Actual Weight 316 Tank no. sounded Ullage Density Volume Meine Ullage Denslly Volume Merrie 317 Slopt. depthm. meters I<g/m3 m3 Tonnes meters Kgtm3 m3 Tonnes 318 319 C· FUEL OIL 320 321 322 323 324 325 326 327 328 329 330 331 332 333 Total C 334 335 D . DIESEL OIL 336 337 338 339 340 341 342 343 Total D 344 345 346 SUMMARY OF DEDUCTIBLES 347 348 STARTING SURVEY FINISHING SURVEY 349 metric tonnes metric lonnes 350 Ballasl water 351 Fresh water 352 Fuel oil 353 Diesel oil 354 Slops 355 Lubrificaling oil 356 Swimming pool waler 357 Anchor & Chain 358 Others 359 360 Total Deductiblesl I I I 361 362 Ed. Odober 15. 1991 • 1.8· MIcrosoft Excel 2.2 6·7 ECE IElJERG Y 11 ~ pal;':: 9 U.N. • ECE • DRAUGHT SURVEY CODE 364 365 DRAUGHT SURVEY REPORT OF CARGO IN BULK BLOADED FOAM "E" 366 UNLOADED 367 Corporale ldenillicalion: 368 369 VesseiMN: Survey no' 370 371 CARGO STATEMENT 372 373 374 Metric T onnes 375 376 Starting Displacement Corrected 377 378 Finishing Displacement Corrected 379 380 Difference in Displacement = TOTAL CARGO IN S'ULK IS: 381 382 383 OBSERVATIONS: Shore scale quantity (if available) M.T.J 384 Note on any unusual situation/s, exception/s from required Uniform Code standard, specific identification 385 (source, drawing no .• date, title, certifying authority) of each ship's document used in translating recorded 386 measurements into weights and. when applicable. reasons for surveyor's refusal or impossibility to perform 387 the survey: 388 389 390 391 392 393 394 395 396 Metric Tonnes 397 Corrected light displacement = 398 Dsductablese :,,9 Lightship= .:.00 Constant= . 401 Mean of previous constants= 402 403 I certify that the constant calculated from this draught survey has been entered into the ship's 'Constant Certificate' 404 405 406 In my judgement the weather conditions, the sea conditions. and the conditions of the ship at the times the 407 draught surveys were conducted, were within acceptable limits and did not adversely affect the accuracy of 408 this survey. This Bona Fide report consisting of _pages, including this page, all duly initialled or signed 409 is issued without prejudice and is for the benefit of whom it may concern. 410 411 412 Name of surveying firm (corporate identification) 413 414 By: 415 (Signalure 01 Surveyor/I) 416 Name/s in print 417 J have partecipate<i In aU stages Of this draught survey, and agree with the results Oblalrned. I acknowledge recelpl ot the sntps eeey. 418 419 Signed: Rank: Name in prinr; 420 421 422 Ed. October 15, 1991 - 1.8 - Microsoft Excel 2.2 7-7 ECE/ENERGY/l9 page 10 PART I SECTION A INTRODUCTION TO DRAUGHT SURVEY AND GENERAL PRINCIPLES What is a draught survey? A draught survey is a method of cargo weight determination by ship's displacement calculations, empty and loaded (or loaded and empty), taking into account any change in weight of the liquids on board. The accuracy of the draught survey will be dependent upon the experience and the care taken by the surveyor concerned, on the documentation of the vessel, on the spirit of co-operation of the vessel crews and of the shore terminal personnel and, last but not least, on the instruments used by the draught surveyor and the weather and sea conditions in the harbour. In the following sections details will be given regarding the procedures to be followed for the draught survey but before going any further, it is necessary to explain the following basic principles: 1. The Principle of Archimedes Referring to the "Principle of Archimedes", I.e. a vessel when freely floating in water, will displace a weight of water equal to its own weight, it is obvious that the weight of the displaced volume of water will not only be the weight of the cargo on board (loaded or unloaded). This weight will also include: the weight of the vessel in light condition, i.e. including all the equipment required for sailing; and the provisions; the residual weight (borne by trade patterns and changing from time to time) ; all deductible liquids on board; ballast: required for stability reasons; fresh water: drinking water and cooling water; bunkers: fuel, diesel and lubricating oil; constant: see definition in the glossary. 2. Variation of displacement of a loaded ship It also follows from the "Principle of Archimedes" that: (a) If a weight of cargo, say 80,000 tonnes, is loaded on (or unloaded from) a vessel floating freely in water of any measured density, then the vessel will sink (or float) into the water until the total weight of water ECE/ENERGY/19 page 11 displaced is equal to the original weight of the vessel plus (or minus) the 80,000 tonnes of cargo which has been loaded (unloaded) and plus (or minus) density variation of the water intervened between the starting survey (first measurement) and the finishing survey (second measurement). (b) If a vessel of fixed weight floating freely in water of low density, for example dock water of apparent density 1,000, is moved into water of higher density, for example sea water of apparent density 1,025. then the vessel will rise slightly in the water because of the smaller volume needed for the same weight of the water displaced. 3. "Empty" ships are actually partly loaded with ballast In the draught survey daily practice one of the complicating elements is due to the fact that "empty" ships (that is before loading or after unloading) are in actuality always loaded with ballast water which makes the calculation of the cargo loaded or unloaded more difficult. The ballast water. that is pumped outboard during loading of cargo. and inboard during unloading, moreover. tends to hide sediments that can be assumed or misidentified with the cargo. When sailing without cargo a vessel has to be ballasted to be at sufficient draught for manoeuvrability and the submerging of its propeller. After arrival at the loading berth, the starting survey is usually carried out when the vessel is still ballasted. Consequently, in order to be able to calculate "the light ship weight", it is most important to determine a reliable ballast quantity. This quantity is, together with fresh water, fuel oils, etc., deducted from the vessel's gross weight. After completion of loading, again ballast tanks are sounded to determine possible residuals. It is commonly accepted that ballast water has the greatest influence on the final tolerance in the out-turn figure. Consequently it must be emphasized that greatest care should be taken during all measurements and observations regarding the ballast. It is not unlikely that in a near future "inbuilt new instruments" of the ship will permit to measure with high accuracy the mass of liquid present at any given time in each tank/compartment of the vessels. 4. Releyance of draught surveys Throughout the world, millions of tonnes of raw and processed materials are bought and sold every day. If any of those materials are carried by ship, it is possible that the weight of the consignment will be measured by a draught survey. This code of standards and procedures has been compiled as an aid to the parties involved. Virtually all draught surveyors have a qualification as Master or comparable professional skill. For other persons who may use this code, definitions of technical expressions used are shown in part 4. The following procedures were compiled taking into account the existing bibliography and references. ECE/ENERGY/19 paqe 12 5. Loading of multiple cargoes It is frequently the case that two or more separate cargo lots are loaded into a vessel, either during a more or less continuous operation at the same port, or sequentially at separate ports. The latter situation may arise due to draught restrictions at the first port, resulting in the need for the vessel to "top-up" at a second port or vice versa at the unloading port(s). Where two or more carqoes can be loaded or unloaded separately and fully, it is preferable that an initial draught survey be conducted, followed by intermediate surveys to calculate the weight of the first and subsequent carqoes loaded or unloaded. On completion of loadinq or unloading, a final survey should be conducted to determine both the total weight and the weight of the final carqo. In cases where loading or unloading is conducted sequentially at separate ports, it is recommended that both a starting and a finishinq survey be conducted at each port. In this case, the startinq survey should verify the weight already or still on board and should also recalculate the "constant" or undefined weiqht of the vessel. In cases where multiple cargoes cannot be loaded or unloaded separately, or where several loadinq heads or unloading grabs are employed simultaneously, it is recommended that only the startinq and finishinq surveys be conducted. The apportionment of the weights of each of the cargoes should then be made by comparing surveyed weight with belt weightometer or shore weight to achieve a factor which is applied to each cargo, as follows: §:yrv!l!:!g w!ight factor (f) Shore weight = Weight of Cargo A = shore weight x (f) Weiqht of Cargo B = shore weight x (f) It is considered that the adoption of this methodology for multiple cargoes will result in an order of accuracy within 0.5', which is accepted for bulk cargoes throuqhout the world. However, where two or more loadinq heads or unloading grabs are employed simultaneously, it is important that the relative errors between individual belt weightometers be checked and recorded frequently. While absolute accuracy is not required, it is important that the weightometers be in harmony with one another, to avoid incorrect apportionment of cargo weights delivered by each loading head. Missing the shore reference the draught surveyor should assume written instructions on the criteria to be used (for instance stowage factor of goods, rail car, etc.). 6. Requirement for gra:yght surveys guring loaging or unloaging It is recommended that draught surveys should always be conducted prior to and on completion of loading or unloading. Where loading or unloading takes place sequentially at several ports, the decision as to whether or not to conduct a pre-loading survey at the second or subsequent ports should be at the discretion of the shipper. In the majority of loading and unloading ECE/ENERGY/19 page 13 ports, the final draught survey certificate forms the basis on which harbour rates, loading. stevedoring and other service charges are levied. as well as completion of the Bill of Lading for the vessel. It is therefore in the interests of both the Shipper or Receiver and the Vessel Agent to ensure that a satisfactory draught survey has been completed. Payment for draught surveys on loading normally is the responsibility of the shipper and on unloading of the receiver. In practice these charges are normally incorporated into the cargo superintending fees. In cases of dispute between the shipper and the ship's master over any draught survey, the master retains the right to arrange for a second, independent survey to be conducted but, in such cases, the cost of the second survey should be borne by the vessel operator. 7. Mopitoring of discrepancies apd trends Particularly for comparison of load port and discharge port draught surveys it is essential to consider the eventual superficial moisture drainage occurred during the transit time. As per world practice, moisture determination takes place on all minerals before loading and after unloading, the difference between the two figures can only be with a negative sign at disport. If and when data are otherwise, this vital element cannot be utilized and comparability becomes less reliable. When all factors and actors work properly this moisture difference should be equal to "bilge drainage" plus evaporation less sprinkled water on the load/unload belts for dust controlling apparatus. It is strongly recommended that arrangements be made between shippers and consignees, whereby copies of Moisture Certificates and Draught Survey Certificates at the loading and out-turn ports are exchanged for each cargo. Where such arrangements have been entered into, the shipper should provide the consignee with the following information by telex, facsimile or other method which will ensure that the information is available prior to discharge: copy of Moisture Certificate(s) at loading port or ports; copies of Certificates of Draught Survey(s) conducted at the loading port or ports: notes provided by the surveyor in relation to sea and weather conditions at the time of loading, together with any comments on deficiencies found with the vessel or its equipment or difficulties encountered in the use of the ship's tables. It is important that the consignee or surveyor at the disport also be provided with a record, certified by the master or a ship's officer of any tonnages pumped overboard from bilges during the voyage as a loss in cargo weight may occur through drainage andlor evaporation particularly on a long voyage involving significant climatic changes. ECE/ENERGY/19 page 14 It can be pointed out that for instance most of the minerals and the coals shipped in bulk, drain moisture during the transit time andlor can be subject to be wetted by snow or rain or water (shore or vessel's dust control installation) or to evaporate during loading and unloading operations, Statistical data collected over decades show that depending upon the cargo size the quantities involved by the ahove phenomena can be significant. Water drainage tends to be directly proportional to the level of superficial moisture at the loading point and to the length of the trip. Data indicate that in case of high departure level of superficial moisture (like 10' or more) and long sailing distance (like 40 days or more), involving significant climatic changes during the voyage, the drainage can be in the order of l' of the cargo weight measured on departure. On lower superficial moisture level on departure (like 6' or 7') and shorter sailing distance (like 15-20 days) with similar climatic conditions from loading to discharge the drainage of superficial moisture stays generally within 0.5' limit or less. In relation to the out-turn survey, this information should also be provided by the consignee to the shipper, so that trends between loading and discharge ports can be monitored and statistical information collected in an organized fashion. The systematic exchange of surveys made in different parts of the world would be equally important. This would allow the dissemination of truly uniform practice, make possible the study of trends. and identify possible anomaly by a given vessel. Such professional tool could be served properly and profitably by a specialized trade publication and possibly be supported by an internationally accessible library where all surveyed vessel data could be classified. 8. Controls before draught survey starts and time allocation The following operations should be routine for the performance of draught survey either at loading or unloading port(s); a check should be made of any equipment malfunctions, including blockages in sounding pipes, etc., which could affect the accuracy of the survey. At most loading and discharge ports, there is pressure to commence operations as sOOn as possible after the vessel has berthed. Despite this pressure, sufficient time ~ be allowed for the surveyor to gain the necessary data before loadinq or unloading is commenced. ECE/ENERGY/l9 page 15 PART 1 SECTION B UTILIZATION OF THE UNIECE DRAUGHT SURVEY CODE FORMS "A" THROUGH "E" 1. fgrmat and procedur~ In order to establish a uniform procedure to be followed between loading and out-turn surveys, the coded format, together with the accompanying explanation given in this document, should be followed. It is understood that slight alterations or additions may be necessary to form "A" lines 001 to 010 due to specific requirements of the principals involved. It should be evident that if cargo is measured at both loading and discharging ports, it is of the utmost importance that the draught survey at each port should be carried out by uniform procedures utilizing the same report format. For multiport loading or discharge the performance of the draught survey by the same individuals will improve the reliability of the final certificates. 2. Vessel acceptance The vessel presented for survey should meet the following: 1. Vessel should be in general good condition and fully afloat. 2. Vessel should present to the surveyor documents as prescribed in the section on documents. 3. The ship should have a zero list but, in any case, the list must not exceed 1/2 degree. 4. The ship should have negligible trim but, in any case, the trim must not exceed the range of the trim corrections furnished with the ship's tank sounding tables. 5. As many ballast tanks as possible should be either empty or pressed up. This is an ideal situation only when the vessel has a negligible trim, and a sufficiently tall tank sounding pipe such that when the tank is fully pressed up, a proper sounding can be taken to verify this "full" state. Whenever the vessel has a trim, or whenever "voids" of air are suspected to be present in a ballast tank, then the most accurate method of obtaining the true weight of the ballast water onboard is for the sounding caps to be left off all top-side (or under-deck) tanks. In this wayan actual sounding can be obtained, and an accurate volume of ballast water obtained from the tank calibration tables. If the sounding caps were screwed tightly down, and the tanks pressed up by overflowing the ballast through the tank ventilators, the ship's staff may be sure the tank is full, but in the absence of a sounding they cannot prove it, and even so, voids of air may still be present. ECE/ENERGY/19 page 16 6. Free ballast in cargo holds should not be present. however, the amount of such ballast must be precisely determined or eliminated before the survey can start. 7. All draught marks. deckline marks and Plimsoll marks should be permanently indicated by raised figures or figures outlined with a weld bead and shall be clearly legible. While the draught readings are being made, there should be no transfer of liquids or movement of heavy equipment which could alter the list or the trim. 8. It should be reported to the surveyor, and he should be alert for, any addition or removal of weight, other than the cargo, which occurs while the survey is in progress. Every effort should be made to delay the requirement for such weight changes until after the survey observations have been completed. 9. Further to item (8) above, it is imperative that no cargo shall be loaded or discharged before the surveyor has completed his initial observations, readings and measurements, and given his express consent for cargo operations to commence. 10. All sounding pipes must be accessible, unobstructed, and capable of serving their intended purpose. All gauges, furnished in lieu of sounding pipes, shall be in proper working order. 3. Accuras;y For the purpose of uniformity, all draughts, soundings and other figures shown in the survey, shall be in the order of two (2) decimal§ as, considering all factors inherent in draught surveys, anything further is considered superfluous. For sea water density, four (4) decimals must be used. 4. Instructions for completing forms "A" through "E" of the UN/ECE Draught Survey Code The identification numbers stated in the following instructions refer to the Line Numbers on the left hand border of the sample Forms "A" through "E" of the UN/ECE Draught Survey Code, Edition October 1991 - 1.8, with crossreferences to line numbers of other Forms. FORM "A" (Preface page) The information presented on this page is meant to encompass the general information pertinent to any cargo weight determination derived from draught survey. There may be additional data related to specific cases. These can be included as detailed in the commentary of each line: .: 001 Indicate if draught survey report refers to loaded or 002 unloaded carqo. In case of need a rubber stamp can be 003 added for such other qualifications of the report such as "Certificate of weight", etc. ECE/ENERGY/19 page 17 004 In these two lines the identification of the corporation 005 or the private professional need to be provided. 006 These two lines are filled with specific indications 007 of branch andlor port offices for larger corporations. 008 In these two lines details of telephone no., fax no. and telex no. 009 need to be provided. 010 These lines are provided for indicating in sequence 011 the vessel's name (in case the vessel should change name while loading or unloading only the last name will be indicated); the call letters which are the letters used to communicate with the vessel; and the survey aerial no.; the latter number needs to be the same as eventually listed in the surveyor's log book. 012 In sequence it is required to indicate in these lines 013 possible previous names of the vessel and the actual classification registry. and registry number. 014 These lines are provided for identification of the year of 015 construction of the ship, the shipyard (with hull no.), and the actual flag of the vessel. 016 In sequence these lines need to be filled with the 017 identification of the corporation requesting the 018 survey; the corporation on whose account the survey is 019 being conducted and, if applicable. the identification 020 of persons. other than the surveyor and of the ship 021 crews, attending the survey. Such attendance of outside entities generally falls in three classes: as joint surveyors, as umpire or just to monitor (generally on behalf of either sellers or buyers). 024 The blank space needs to be filled with the indication of the port. 025 The blank space needs to be filled with the indication of the type of cargo being loaded or unloaded. It must be clarified that by including such an indication in the survey the surveyor does not undertake any liability on the type andlor quality of the cargo being loaded or unloaded. 026 In the blank space the surveyor should identify the hold's number in vhich cargo vas loaded or unloaded. In case of holds loaded only in part such detail can be listed in the footnotes or in an annex of the survey report. 031 The first line will serve to indicate the date of the starting 032 and the date of the finishing surveys. The second line will be used to indicate the number of hours used to make the surveys. ECE/ENERGY/19 page 18 033 Identify the name (or the names) of the surveyors performing the starting and the finishing survey. 034 035 Identify the Master. It is not unusual that the Master of the finishing survey may be different than the Master of the starting survey. 036 These lines will serve to identify the Chief Officer and the Chief 037 Engineer. Not infrequently the names will be 'different from starting to finishing survey. 038 In these four lines should be identified respectively the names and 039 the ranks of the witness of the draught readings and of the tank 040 soundings. Not infrequently the names in these lines will be the same 041 as the Chief Officer (who generally assists in the draught readings) and of the Chief Engineer (who generally assists in the tank soundings). 042 In this line should be identified the terminal, pier, or berth where the vessel was located at the time of the starting and finishing surveys. 043 These lines are provided for recording the weather temperature in 045 centigrade and the sea conditions. 047 Indicate the heading of the ship. 048 Indicate the direction of the wind. 049 Indicate the speed of the stream in Km/h only in ports where such element is of relevance. 050 Indicate status of the tide at the time when the starting and finishing surveys were conducted. 052 Indicate such information on ice only when applicable. 054 Cargo handling equipment brought temporarily on board should be 055 described in these lines and tare weight of it properly identified. 056 Normally in these lines is identified the weight of the anchor and of 057 the chain and/or other temporarily missing ship's equipment. FORM "B" 058 Specify in the appropriate box if the survey relates to the cargo 060 loaded or unloaded. 061 In these two lines the identification of the corporation or the 062 private professional need to be provided. ECE/ENERGY/19 page 19 063 Identify the vessel name and the serial number of the 064 survey. 065 Tick the appropriate box to record the criteria for calculating the 072 corrections. 073 Identify the ship's approved hydrostatic data. In this connection it 078 needs to be stressed that the range of hydrostatic data shall be from light ship draught to the deepest draught permitted by the Load Line assignment. 079 Tick the appropriate box regarding the degree of tank calibration. 081 082 Enter the range of "tables for correcting tank calibrations for trim" 083 available. In case trim should exceed the range of tables, the surveyor will stop his activity until such time when the ship will be trimmed again within the range of the approved tables. 084 Enter in sequence the shipyear no., the hull no. and the place 085 and date of the document from which the information was obtained. 086 Any discrepancy which would be obvious to a qualified surveyor should 087 be summarized in these two lines. In case space should not be sufficient, an extra page can be added to explain more in detail the problems faced. 088 Ship's particulars in these lines can be filled in by the Master in 097 advance of survey start in order to reduce the time of the preliminary formalities. Naturally the surveyor can ask to verify the relevant figures from the original approved documents. Calculation of Constant 090 At the termination of the survey which takes place when the cargo is not on board, i.e. either before it has been loaded or after it has been discharged, the following calculation shall be made for comparison with the previous history of the Ship: (line 090) = Corrected Displacement (Unloaded) (line 170) Light ship Weight listed in approved Trim & Stability Booklet (line 092) Constant = This undefined weight should not be accepted as a "constant" for the vessel, but should be recalculated at each draught survey and should be recorded on a light ship correction certificate which should be maintained on board the ship, recording the following information: ECE/ENERGY/19 page 20 "Constant" Certificate f?- P-L-~C--E------~~;;~~~-~;------~-----;~~;~~;;;------J----;~;;~;~;-------: A A CORRECTION TO j I IDENTIFICATION ! LIGHT SHIP CHIEF SURVEYOR : OR STAMP ; WEIGHT OFFICER i t I METRIC TONNES ! --r----- ,---------------------~----------l----------i-------------------~ I ; T E -------------------------------~----------~------------------------------- so that large discrepancies could be noted for future reference. 098 The surveyor should enter this set of vessel particulars in connection 106 with starting and finishing survey. 107 Depending upon the conditions found, enter on each of these lines the 109 term "Satisfactory" or "See Form E". When the latter designation is used, the discrepancy in the referenced item should be briefly described in the blank space on Form E or on additional, attached sheets. 110 Space available to list additional pertinent details and/or short 113 remarks on previous lines. FORM "c" 117 Specify in the appropriate box if the survey relates to the cargo 119 loaded or unloaded. 120 In these two lines the identification of the corporation or the 121 private professional need to be provided. 122 123 Identify the vessel name and the serial no. of the survey. 126 Enter starting and finiShing hour of draught reading operations for starting survey and for finishing survey. Indicate hours from 00 to 24 and minutes from 00 to 60. ECE/ENERGY/19 page 21 Beading the draughts 129 The draughts shall be read at the forward and after marks and at 130 midships, port and starboard, and recorded immediately before cargo 136 loading/discharging operations commence and, again, immediately after 137 cargo loading/discharging operations are completed. 145 All draught readings shall be witnessed and agreed to by a licensed 146 deck officer (complete line 39 on Form "AtI). If the readings cannot be properly observed from the pier or from a ladder over the side, the readings over the aide ahall be made from a small boat manoeuvred to the proximity of the marks. If turbulent conditions of the water surface prevent accurate readings and when local conditions will allow, a draft reading tube which dampens out the surface oscillations shall be employed. At exposed ports, the use of a boat may be impractical or even dangerous. In such situations a suitable alternative is to read the nearside draught marks and to employ a manometer to determine the offside draughts, by calculating proportionally the effect of vessel heel. The use of a manometer can also enable calculations of heel when the vessel is subject to rolling as a result of sea conditions. Irrespective of the availability of the midship draught marks, the midship draughts, port and starboard, should be determined by measuring the freeboards from the deck line to the waterline. To obtain an accurate depth of the ship, add the Summer freeboard, listed on the ship's Load Line Certificate, to the Summer Draught. It needs to be noted that the Load Line Certificate should always be sighted as this is the legal source for this information (not the Plimsoll mark on the side of the vessel). From this depth, subtract the port and starboard freeboards, thus obtaining midship draughts. 131 The mean draught at the mark is the numerical average of the readings 138 observed on the port and starboard sides. Correction of Draughts from Marks to Perpendiculars 133 The draught readings at the marks must be corrected to the 134 equivalent readings which would obtain at the Forward and After 140 Perpendiculars as specified by the following formula: 141 Draught at Perpendicular Corr. to PP = .:t. ( I ( Dl x = Draught Mark D2 ) ) at + Corr. to PP where: T = Trim between draught marks 01 = Distance between draught marks D2 = Distance from draught mark to perpendicular ECE/ENERGY/19 page 22 The sign of the Corr. to PP depends on the observation of the slope of the waterplane between the location of the mark with respect to the location of the perpendicular. 143 Tbe Draught forward and after mean is the numerical average of the draughts at the Forward Perpendicular (line 134) and at the After Perpendicular (line 141). 147 Tbe Draught midship mean is the numerical average of the draughts read port and starboard at midships (lines 145 and 146). 148 If the midships marks are not located at a position balf way between 149 the Forward and After Perpendiculars, the mean reading at the marks (line 147) must be corrected to this midpoint location by the following formula: Draught at Midships = Draught at Midship Mark + Corr. to Midships Corr. to Midships = T ;t D1 x ML Where: T D1 ML = Trim between draught marks = Distance between draught marks = Distance from midship draught mark to the vertical at the half-length between the forward and after perpendiculars The sign of the Corr. to Midship depends on the observation of the slope of the waterplane between the location of the mark with respect to the location of the midships. ~alculation of Hog or Sag 150 Deflection of the hull, i.e. deformation of the bottom of the ship from a straight line to a curved line either concave (SAG) or convex (HOG) is determined from the following formula: (line 150) = (line 149) - (line 143) if resulting sign is + the ship has SAG if resulting sign is - the ship has HOG Calculation Qf M/M/M Draught 151 The Mean of the Means Qf the Mean draught is an approximate method 152 of correcting the calculated displacement for the effect of hull 154 deflection. This method, which is described in paragraph (a), shall be used except in the special situations defined in paragraphs (b). (c), or (d). ECE/ENERGY/19 page 23 (a) If bog or sag exists. the draught applied in the displacement calculations shall be adjusted in accordance with the following formulas: M = Pfp + pQP (line 143) 2 M + MS M/M = u........:..___. ...... 2 (line IS1) M/M/M = M/M + MS (line 152) 2 where: Pfp = draught at For'd Perp. (line 134) Pap = drauqht at After Perp. (line 141) MS = drauqht at Amidships (line 149) M/M/M = draught applied in the displacement calculations (line 152) (b) If the ship is provided with an approved table which furnishes a correction for hull deflection, then this correction shall be used in lieu of the correction prescribed by paragraph (a). A statement of such usage shall be clearly documented on Form "E", so that the same methodology will be applied in any other drauqht surveys conducted on the same voyage. (c) If it is agreed before the voyage commences, that the displacement will be calculated by integration of the transverse section areas representing the immersed portion of the hull as actually trimmed and deflected, with appropriate correction for the weight of the shell plating and the appendages, then this method shall be used in lieu of the correction prescribed by paragraph (a). The total hull deflection measured amidships shall be apportioned at each station between the Forward and After Perpendiculars by the parabolic coefficient set forth in Table I. A statement of such usage shall be clearly documented on Form "E" so that the same methodology will be applied in subsequent surveys as agreed. ECE/ENERGY/19 page 24 Table 1 .------------------------------------------------------------------------------1 Hog - Sag Correction to be applied to station draughts when hydrostatic properties are calculated for actual trimmed water line Apply proportional correction to the draught taken from a trimmed straight line through amidship. Correction (+) for hog and (-) for sag Station Proportion of hog or sag F.P. l.00 112 .81 1 .64 2 .36 3 .16 4 .04 5 0 6 .04 7 .16 8 .36 9 .64 9-112 .81 A.P. 1.00 (d) If it is agreed before the voyage commences that the correction for hull deflection be related to the waterplane area, then the method described below shall be used in lieu of the correction described in paragraph (a). Such usage shall be clearly stated (Form "Eff) so that the same methodology will be applied in subsequent surveys as agreed. When the ship is hogged: D = M - f x (M - MS) When the ship is sagged: D = M + f x (MS - M) D = Draught applied in displacement calculation (line 154) M = Mean of draughts at Forward and After Perpendiculars (line 143) MS = Mean of draughts measured at Amidships (line 149) f = Coefficient from Table II where: ECE/ENERGY/19 page 26 (a) In the relatively unusual case where the hydrostatic data is referred to the moulded base line. the thickness of keel plate (line 153) must be deducted from the M/MVM draught before entering the hydrostatic tables. (b) In the event that the ship has hydrostatic curves instead of tables, displacement (1), i.e. line 161, shall be obtained by reading a displacement. from the curves at the closest delineated calibration, and applying a correction for the actual MIMIM draught as follows: 0(1) = DC + TPC x (difference between CD and M/M/M) where: 0(1) DC CD TPC = Displacement (1) (line 161) = Displacement read at calibration = Calibration draught utilized = Tonnes per centimetre The sign is applied according to whether the MIMIM is above or below the calibrated draught which was utilized in the calculation. Calculation of displacement (2) 166 Displacement (2) = Displacement (1) + Trim Carr. (line 166) (line 161) (line 164) This calculation is not necessary if the displacement is calculated directly by the method set forth in paragraph (c) of the section on calculation of MIMIM draught. which includes the effects of both trim and hull deflection, i.e. the value obtained by such method is Displacement (2). Calculation of trim correction 162 (a) Except when the displacement is corrected for trim by the 163 method described in paragraph (c) of the section on the 164 calculation of MIMIM draught or except when trim correction tables are available. the correction for trim shall be calculated by means of the following formula: LCF Carr. = (line 162) TPC x LCF x T x 100 LBP The sign of the correction shall be in accordance with the following table: ~~~~~~~~~~~~~r~~~~~~~~~~~~~~~~~~~~~~~~i-! Aft t - ! + ~------------~--------------~------------4 ! Fwd ' + ~----------------------------------------- Nemoto Carr. (line 163) 50 x (dM/dZ) x T2 LBP ECE/ENERGY/19 page 25 Table II Bog and lag correction factors _, • I I: , • I •••• I , • I , •• rsc x 97 .:~5 M4te~~~~~e C~et!~:ler.: : --CEP-;-i--- , • t f , ••• I t I ~·T~:~ .6 . i .s .~ Calculation of trim 155 The forward and after trim of the ship shall be calculated from the draughts at the perpendiculars (lines 134 and 141), using the following formula: Trim = Dap - Dfp where: Dap = draught at After Perp. (line 141) Dfp = draught at Forward Perp. (line 134) + shall be indicated as Trim Aft - shall be indicated as Trim Forward petermination of Displacement (1) 153 Except as noted in paragraphs (a) and (b), displacement (1) is to be 161 extracted from the ship's approved hydrostatic tables for the M/M/M draught by means of linear interpolation. ECE/ENERGY/19 . page 27 The Nemoto Correction is always + where: TPC = LCF = T = LBP = (dM/dZ) = Tonnes per centimetre immersion (line Ogg) Longitudinal centre of flotation (line 100) (metres) Trim between Perp. (metres) (line 155) Length between Perpendiculars (metres) (line 090) Difference in moment te change trim one centimetre for two draughts, one SO cm higher than the mean observed draught and another SO em lower than the mean observed draught (metre-tonnes) Then Trim Corr. = ± LCF Corr. + Hemote Corr. (line 164) 164 (b) If the ship has approved tables which provide a correction to the displacement for the effect of trim, then this correction shall be utilized in lieu of the calculation described in paragraph (a). Calculation of density correction 157 Samples are to be taken with a "tumble-fill" or equivalent type of 158 salinometer pot. 159 The results of all tests should be averaged and should be compared with 167 other recent tests at the port or berth. If unexpected variations occur, the samples should be retaken and tested again, if necessary at one-metre intervals on both port and starboard sides of the vessel. In many ports the density of dock water changes with depth and tide. Consequently a number of samples should be taken at various levels and locations to obtain a reliable mean density. Tidal variations can also affect density. The density meter should be kept clean, otherwise it is liable to show unacceptable deviation from actual density. (a) The density of the water in which the ship is immersed shall be measured either immediately before or immediately after the draughts are read. The measurements shall be made with a glass hydrometer, certified by the manufacturer to be accurate, and calibrated to read weight per unit volume in air. Serial number and identification of the instrument shall be entered on line 159. The density shall. initially, be measured amidship, near the water surface and. again, near the bottom of the keel. If the readings are identical single additional readings shall be made at the bow and the stern. If the readings are not identical to the previous readings then readings at two levels shall be made at the bow and the stern. The density (line ls7) shall be the average of all readings taken. ECE/ENERGY/19 page 28 (b) The weight of the ship and all that is in her must be adjusted for the difference in the actual weight, in air, of the water displaced by the ship and the assumed weight used by the naval architect in computing the draught versus displacement table. This correction is made in accordance with the following formula: Density Carr. (line 167) RD - MD Displacement (2) = RD Z (line 161) where: RD = Density of water specified in the ship's hydrostatic data (line 158) MD = Average density of water as measured in accordance with paragraph (a) (line 157) Disregard the resulting algebraic sign because the correction will be applied in accordance with the rule set forth in the next paragraph. Calculation of Displacement (3) 168 Displacement (3) = Displacement (2) ± Density Corr. (line 168) (line 166) (line 167) The sign of the Density Correction is dependent on the relationship between the measured density and the reference density used in the hydrostatic data. Thus, if the measured density is less than the reference density. the density correction is minus and vice versa. Calculation of total dedyctibles 169 In the draught survey calculations there must be a means for discriminating between the weight attributable to the cargo and the weight attributable to other burdens within the ship. The means for this is provided by identifying and summing all non-cargo weights as measured and calculated on Forms "D/l", "0/2", and "D/3". The following special instructions apply: (a) In the starting survey, all the deductible weights, which are on board at the time of the survey, must be identified and the weight attributable to each must be stated in the draught survey report. Summation of these items furnishes the Total Deductible Weight. (b) Unless important alterations occurred from starting to finishing survey such as discharge of fresh water near completion to accommodate cargo; in the finishing survey. the procedure required by paragraph (a), need not be repeated. Instead, only the ballast tanks, on Form "0/2", must be measured and calculated a second time. The weight, at the time of the finishing survey, of the fuel, fresh water, and other consumable liquids shall be determined by deducting the "in port" consumption from the weight reported at the starting survey. ECE/ENERGYl19 page 29 (c) If fuel, fresh water, or other consumables are taken on board between the start and finish surveys, the increase in weight indicated by the delivery invoices, shall be calculated into the change in weight due to "in port" consumption, provided such indicated weights appear .treasonable". Otherwise, the actual weights of fuel and water should be determined at the initial ~ final draught survey. (d) In the situation where the vessel is in port for a protracted period between the starting survey and the finishing survey, the measurement and calculation of the deductible weights on Forms "011", "D/2", and "D/3" shall be conducted at both the starting and the finishing surveys. (e) In the unusual case where the condition of the ship, at the time of the starting survey, is not conducive to the accurate determination of the tankage, the measurements and calculations listed on Forms "D/1", "D/2", and "D/3", with the exception of the Ballast Tanks, may be deferred until the finishing survey. The weight attributable to the "in port" consumption shall be added to the weight reported at the finishing survey. This situation should be noted in the footnotes. (f) In some exceptional cases there is a non-cargo weight adjustment which must be dealt with differently than provided for on Form "0/3", lines 357-359. This occurs when a significant weight, which is part of the ship's structure or basic equipment (i.e. is included in the approved light ship weight), is not on board at the time of the survey. If the deficiency exists at the time of both the starting and the finishing survey, it has no effect on the cargo weight but it will increase the constant as shown on Form "B", line 090. If the deficiency exists at the time of one of the surveys but not the other, it will affect the cargo weight also. Therefore, the deficiency must be corrected in the final cargo weight as shown on Form "E", lines 376-380. The details of such correction shall be included on Form "E". Calculation of Final Corrected Displacement 170 Corrected Displacement (line 170) = Displacement (3) (line 168) Deductible Weight (line 169) FORM "D/l" This form needs to be filled during the starting survey. 178 Indicate in the appropriate box if the survey relates to the cargo 180 loaded or unloaded. 181 In these two lines the identification of the corporation or the 182 private profeSSional need to be provided. 183 Identify the vessel name and the serial no. of the survey. 184 ECE/ENERGY/19 page 30 185 Enter with the starting and the finishing hour of ballast and fresh 186 water soundings; indicate hours from 00 to 24 and minutes from 00 to 60. Enter subsequently with date or dates and specify trim of the vessel while the soundings for ballast and fresh water took place. Qallast tanks 195 Enumerate in sequence each compartment containing ballast water (one 210 for each line from forward to after). All ballast tanks must be sounded with a calibrated steel sounding tape and water finding paste. At exposed berths, where vessel movement could cause errors in tank soundings, the soundings should be made at least three times with a steel tape and paste, or alternatively with a float, and the average taken of the readings. Water in ballast tanks must be measured by sampling via the sounding pipes with appropriate equipment (such as a small pump and plastic tubing) and the density calculated, using equipment and procedures as set out in lines 157 to 167. Corrections for heel and trim must be applied to soundings, including allowances for unpumpable volumes in "dry" tanks. Any inadequacy of tank tables in regard to capacities or corrections for trim, should be noted on the surveyor's report. The heading of all columns of this form is self explanatory except that a few comments are in order: (a) Every tank should be sounded scrupulously. Expressions such as "full" or "empty" with the corresponding, appropriate figure against it shall not be used. (b) The trim of the vessel must not be ignored. "Pocketing" often leaves voids in supposedly "full" tanks. Small quantities coupled with large trims can render prismatically shaped volumes, the size of which must be arrived at by solid geometric mensuration, should sufficiently arranged tables not be available. (c) Special attention should be given to the density of the liquid in the tank in order to arrive at an accurate weight. This is especially important in ascertaining weights in ballast tank since, for obvious reasons. the specific gravity may vary from less than 1 through 1.025. To assume the latter (or the first) when, in fact, the actual figure is somewhere in between can lead to large errors in the bigger vessels. 210 Bilges: all bilges are to be sounded or confirmed dry by visual 214 inspection. Bilges pumping certificates should be placed on board and the master should be requested to keep an accurate record of any bilges pumped overboard during the voyage. This record should be handed to the consignee's surveyor at the discharge port and a copy retained on board. To secure reliability of the data the bilge water should be first pumped in a calibrated compartment and from there overboard each time that such compartment is full. This is a very critical point, failing which, reconciliation of loading and discharging port results can become difficult, as explained in previous paragraph. ECE/ENERGY'/19 page 31 215 Duct keels and swimming pools: care must be taken to include soundings 218 of special spaces such as duct keels, or inspection of the swimming pools, etc., in the starting and finishing conditions. Water in the swimming pools shall be listed separately, from ballast of all other compartments, and entered in line 357 of Form "013". 219 Total weight in metric tonnes of ballast water listed in previous 220 lines should be entered on the right hand side and also on line 351. 223 Fresh water: the quantity of fresh water listing each tank is to 233 be established by sounding or by gauge if fitted, and corrections made when applicable for heel and trim. The total is to be entered on line 352 of Form "D/3". 234 Enter in this space an indication of possible obstructions in sounding 235 tube or tubes and identify each problem encountered. In case of need add an extra page to illustrate in detail the problem and how it was faced in the situation. FORM "0/2" This form needs to be filled during the finishing survey. 235 Indicate in the appropriate box if survey relates to cargo 237 loaded or unloaded. 238 In these two lines the identification of the corporation or the 239 private professional need to be provided. 240 Identify the vessel name and the serial no. of the survey. 241 242 Enter with the starting and the finishing hour of ballast (and 243 possibly fresh water) soundings: indicate hours from 00 to 24 and minutes from 00 to 60. Enter subsequently with date or dates and specify trim of the vessel while the soundings for ballast and possibly fresh water took place. 252 All ballast tanks need to be listed in the same order as in form "D/1" 267 and the value sounded for each tank entered in the appropriate columns with necessary corrections. 268 All bilges checked and listed as in form "D/l" with pertinent 271 data if necessary. 272 Duct keel and any other compartment listed in form "D/l" needs to 275 be listed also in this form and applicable values entered in the appropriate column. Surveyors are warned that the erroneous assumption possibly made on "empty" or "full" duct keel, eventually due to the difficulty of sounding may lead to surprising discrepancies. ECE/ENERGY/19 page 32 280 As explained in previous section. fresh water generally does not need 289 to be sounded again if it was sounded for the starting survey unless for some special situations like for instance when at last moment ballast water is pumped out of board to load more cargo. Under such circumstances it is necessary to repeat the fresh water soundings. 292 Enter in this space an indication of possible obstructions in sounding 293 tube or tubes and identify each problem encountered. In case of need add an extra page to illustrate in detail the problem and how it was faced in the situation. FORM "D/3" 305 Indicate in the appropriate box if survey relates to cargo loaded 306 or unloaded. 307 In these two lines the identification of the corporation or the private 308 professional need to be provided 309 Identify the vessel narne and the serial no. of the survey. 310 313 The headings of the columns are self explanatory. 345 Similarly to soundings made for ballast and water determinations, under section C (lines 319 to 334) the figures for fuel oil on board shall be measured and entered with the identification of each tank in the sequence order from forward to after. unless for special circumstances it is sufficient to measure fuel oil only for the starting survey. For fuel consumption during loading or unloading the Chief Engineer's data (provided reasonable figures are offered to the Surveyor) are an acceptable method of calculating final fuel weight for finishing survey. Naturally in this case only the last column (weight metric tonnes), under finishing survey will be entered with the appropriate calculated numbers. In case of any slop tank also the content of such compartment needs to be sounded and pertinent data entered with specific identification of each tank after the data of fuel oil. Total C for fuel oil will be entered on line 353. as appropriate under starting and finishing survey. The summation of slops will be entered in line 355 under starting and finiShing survey. 335 Similarly for diesel oil. the same operations listed above for fuel 344 oil, need to be done with the same criteria. In this case, also. any large difference in figures between the initial and the final survey needs to be investigated and, if necessary. all tanks sounded again and weight determined using the appropriate specific gravity for the fuel. ECE/ENERGY/19 page 33 Summary of deductibles 346 All figures of these lines have to be entered accurately, filling 362 in the starting survey and the finishing survey data as follows: 351 In the starting survey table needs to be entered the summation of line 219. In the finishing survey tables the summation of line 276. 352 In the starting survey the summation of line 232 and in the finishing survey the summation of line 290. 353 Summations of line 333 need to be entered under the respective starting and finishing table. 354 Summations of line 343 respectively under starting and finishing. 355 Subtotals possibly entered in section of fuel oil need to be entered in this line respectively under starting and finishing survey as appropriate. 356 The totals of lube oil shall be generated in the total quantity directly from ship's documents and entered under starting and finishing survey. 357 The water contained in the swimming pool must be entered as appropriate under starting and finishing survey. 358 Enter the weight of the anchor(s) and chains, under starting and finishing. 359 Enter in this line every other weight other than cargo identified in the starting and finishing survey. 361 Summation of all above listed items represents the total weight of the deductibles to be entered in line 169 and to be deducted from the starting and the finishing displacement of line 168 to obtain the displacement corrected tor deductible of line 170. FORM nE" This is the concluding part of the draught survey. 364 Indicate in the appropriate box if survey relates to cargo 366 loaded or unloaded. 367 In these two lines the identification of the corporation or the 368 private professional need to be provided. 369 Identify the vessel name and the serial no. of the survey. 370 ECE/ENERGY/19 paqe 34 376 Enter the corrected displacement of the startinq survey, as per line 170. 378 Enter the corrected displacement of the finishinq survey as per line 170. Calculation of cargo weight 380 Khen both the startinq and finishinq surveys have been completed: Carqo = W'eiqht (line 380) Corr. Displacement Loaded (line 170) Corr. Displacement Unloaded (line 170) 383 When such data is available and for statistical purposes only, enter in the provided space the shore scale quantity converted in metric tonnes. the scali weight should in no way whatsolvlr influence the cargo weight as mla.ured by the surYlyor. He is obligld to report his result hQnlstly and strictly on the basis of the measurlments and calculations he has made. 389 These lines should be filled with illustration of unusual situations 400 (extra paqes can be added if needed); with specific identification of vessel's documents used; and, in case of need, with the identifications of the reasons for surveyor's refusal or impossibility to perform the survey. In such instances, provided facts are objectively listed, the surveyor shall be entitled to the aqreed fee like if the survey had been made. 401 Enter calculation of the constant. 408 In the situation described in the previous sentence these four lines 411 need to be reworded (Le. "where not within" - in lieu of "where within" and "did adversely affect" instead of "did not adversely affect") or voided completely. 412 Enter total number of paqes includinq pages possibly added to the seven paqes of the UN/ECE Drauqht Survey Code Forms (Ed. October 1991-1.8). 416 In these two lines the identification of the corporation or the private 417 professional need to be provided. 418 Signature of the surveyor or surveyors and indication underneath of the 422 full names in print and title(s). Surveyors are warned that each page of the survey needs to be siqned or initialled by the surveyor(s). Moreover it is good practice by the surveyor to tender the manuscript of the document for the siqnature of the Master (or alternatively of the Chief Officer and the Chief Engineer) only as witness and for endorsement of the vessel's data by themselves released to the surveyor. ECE/ENERGY/19 page 35 PART 1 SECTION C FACTORS AFFECTING DRAUGHT SURVEYS Quite apart from the points made in other parts or sections of this code certain inherent limits of approximation remain in this technology like in any other weighing process meant to measure quickly and inexpensively large masses of materials. 1. Incorrect hydrostatic information or draught marks Investigations carried out in specially performed draught surveys have indicated that there can be significant errors in the determination of displacement due to typographical errors or arithmetical errors in the ship's hydrostatic tables. This could be improved if the tables furnished to the surveyor bore an approval stamp by the flag government or the classification society. After a number of years careless re-painting of draught marks, especially if they have not been permanently marked on the hull, can cause erroneous readings. If there is any doubt, the draught marks should be re-sited at the next dry docking. 2. Incorrect tank calibrations This is normally ascertained after a number of draught surveys when a constant error may appear. It may be verified by a careful draught survey when just the tank/tanks in question are filled or emptied with no other weight changes. Classification societies, upon request of the shipowners, may however issue the special calibration certificates for each tank or compartment of the vessel. 3. Mud and/or scale in ballast tanks The quantity of mud and/or scale will increase over a period of years, depending on the sediment in any ballast taken, on the extent of scale formation and on the cleaning which is carried out. It is difficult to quantify. The effect on ballast calculations can be minimized unless there are reasons to the contrary by leaving a measurable quantity of water in the ballast tank instead of pumping it dry. The calculation would then use a difference in known water quantities rather than assume that a tank is completely empty: in this way the error would be confined within the density differential of the mud and the ballast water. Regularly, large bulk carriers arrive at unloading ports with a slight trim by the head as a result of burning fuel from the aft located fuel tanks during long sea passages. Since generally the sounding pipes are located aft only, dry soundings of ballast tanks do then not necessarily mean that no water is present, since any water will accumulate in the fore end. When the ballast tables are subsequently entered with zero sounding and the head trim, ECE/ENERGY/l9 page 36 considerable quantities of residual ballast water are found. Again, this water does not actually have to be present. Consequently, when one assumes empty or tabulated quantities. both may be wrong. 4. Bottom shell growth Marine growth on the bottom of the ship, especially if dry docking is delayed or there is a failure in the antifouling paint. adds weight to the ship. But. because this weight does not change between the start and finish surveys, it has nO effect on the calculation of the cargo weight. unless the vessel is docked for a long period or the antifouling paint deteriorates. 5. Wtter disturbtnce Normally due to wind, swell, or passing traffic. Accurate reading of the draught requires the use of a draught reading tube such as one of those described in Section I of Part 2 "Draught Survey Instruments". 6. Variations in sea-water density If a loaded vessel has a small underkeel clearance, the sea-water may hold mud/sediment in suspension, or its density could be affected by chemicals in solution. This may be apparent from the bottom layer sample. If it is suspected, a sea-water sample should be taken at the maximum draught as a check. In river ports or in proximity of river mouths or of industrial plants there may be numerous layers of water with differing densities, which may substantially affect the accuracy of the water sample unless properly detected. 7. Vessel squat When a vessel is moored in a tidal stream or a fast flowing current, in shallow water, it will squat in the water, i.e. its draught will increase. This is due to a fall in the pressure of the water between the bottom of the hull and the sea-bed. The sinkage is due to a number of complex factors due to the hydrodynamic properties of the hull, especially where underkeel clearance is small and which cannot be accurately determined by theoretical calculations. There appears to be no effect at current speeds below 2.5 knots. If conditions are conducive to squat the surveyor and the master should monitor carefully that the vessel is fully afloat and not touching the bottom, and for best accuracy, consider waiting for slack water, or shifting the vessel to another berth where the effects of squat are known to be less. 8. Asymmetrical hull deflections If the mean draught midships differs from the mean of the forward and after draughts it is assumed that the deflection of the hull shape takes the form of a parabolic curve. This assumption is inherent in the two-thirds and quarter-mean methods of correcting for hull deflection. If there is no difference between the mean draught midships and the mean of the forward and after draughts it is assumed that the hull shape has not been deflected. Both ECE/ENERGY/l9 page 37 assumptions may be incorrect. In practice, the hull deflection may not be a parabolic curve or there may be deflections between the ends of the vessel and the midships points {i.e. as a modified sine curve}. If the draught is not read at all six draught marks, the hull may be twisted without the fact being known. 9. Solar bendipg Vessels of approximately 50,000 tonnes deadweight and upwards may be subject to hull deflections caused by solar bending of the deck and structure above the waterline. The effect would normally be a hogging which can be appreciable. Some readings taken on a 74,000 tonne. dwt bulk carrier and reported in "Seaways" (March 1987) showed that the fully loaded vessel was sagged Scm. at 0700 and hogged 27.5cms at 1700 on the same day with no movement of weight within the vessel (apart from normal oil/water consumption for an anchored vessel). 10. Use of approximate methods for corrections The mathematical methods used to correct for trim and/or hull deflection (hog or sag) if these conditions exist, are approximations because of limitations of time, expense and the work site. However, if the same methods are correctly and uniformly employed in all surveys, the resultant error in the exact cargo weight will be minimal. However, if in better equipped ships, correction tables for trim andlor hull deflection are available, then such tables should be used instead of the approximate methods. ECE/ENERGY/19 page 38 PART 1 SECTION D IMPROVING ACCURACY In a draught survey operation several parties are involved and it is to the advantage of each party to join the efforts to increase the accuracy. The parties involved are: A. The buyers, the sellers. the charterers. the terminals and th, vessel 's staff Assuming that buyers, sellers and charterers are equally concerned about the correct weight of the cargo, also for the master (respectively chief officer to whom the responsibility of the cargo weight is delegated) shortages and discrepancies may be a problem. In order to avoid this, it is strongly recommended that, once a vessel is nominated, a telex be sent to the master informing that the bill of lading weight will be established by draught survey. This, in order to indicate that his vessel is to meet certain requirements at time of arrival at load/disport. If not, the vessel may be placed in off-hire and the masterlowner be held responsible for all related costs. B. T,l,x format to advis, mast,r of draught survey A suggested format for such a telex is quoted below: Suggest,d tel,x format To the Master, M.V. Copy to performing surveyor From _ (the charterer's agent) Subject: Presentation of vessel on arrival in full readiness for draught survey to be conducted in accordance with the UN/ECE Draught Survey Code 1991. Sir, Please be advised that, under the terms and conditions of your charter party, you must present your vessel in full readiness for an independent marine surveyor, acting on our behalf, to conduct a draught survey to establish bill of lading quantity. The draught surveyor will board your vessel upon arrival at the cargo handling berth. 1. Vessel shall arrive at the loading (or unloading) port with a trim not exceeding her ballast tank trim correction tables and without list (in any case the list must not exceed 1/2 degrees). ECE/ENERGY/19 page 40 Clause in the charter party (Copy to be sent to master and to charterer's agent at loading and unloading ports). The weight of the cargo will be determined by draught survey. conseqently: 1. Vessel shall arrive at the loading (or unloading) port with a trim not exceeding her ballast tank trim correction tables and without list (in any case the list must not exceed 1/2 degrees). 2. Vessel shall furnish the following documents which are approved or otherwise suitably verified as being applicable to the ship: (a) Hydrostatic tables (or curves) (b) Trim and stability booklet (c) Calibration, tables for all tanks - ballast, bunkers, freshwater, slops, etc., with corrections for trim (d) General arrangement plan (e) Load line certificate (f) Record of the ship's constant 3. The draught marks, forward, aft, and amidships, the deck line, and the plimsoll marks, all port and starboard shall be clearly legible and cut in, raised, or marked with a weld bead on the shell plating. 4. Vessel shall not take, pump out or switch from one tank to another, ballast freshwater or bunkers while draught survey is carried out. 5. It should be avoided having ballast in one of the holds. Otherwise loading operations not to be started before hold is pumped out completely. 6. Unless properly calibrated, the ballast tanks should, or be made empty, before survey starts. (This individually per tank). Sounding pipes must be intact, free of blockage and readily accessible. 7. Loading/unloading operations should not start until the draught readings and the density readings have been completed. Tank soundings shall be made immediately thereafter. The condition of the ship or the availability of ship's personnel should not interfere with or delay the timely completion of this operation. 8. Notice of readiness will be accepted only when the vessel is ready for a draught survey and complies with the above mentioned points and no other condition may exist on board which will interfere with a timely and accurate draught survey. 9. Officers and crew are requested to offer the surveyor their fullest cooperation in the performance of his duties. ECE/ENERGY/19 page 39 2. Vessel shall furnish following documents which are app;~oved or otherwise suitably verified as being applicable to the ship: (a) Hydrostatic tables (or curves) (b) Trim and stability booklet (c) Calibration tables for all tanks - ballast, bunkers, freshwater, slops, etc., with corrections for trim (d) General arrangement plan <e) Load line certificate (f) Record of the ship's constant 3. The draught marks, forward, aft, and amidships, the deck line, and the plimsoll marks, all port and starboard shall be clearly legible and cut in, raised, or marked with a weld bead on the shell plating. 4. Vessel shall not take, pump out or switch from one tank to another, ballast freshwater or bunkers while draught survey is carried out. 5. It should be avoided having ballast in one of the holds. Otherwise loading operations not to be started before hold is pumped out completely. 6. Unless properly calibrated the ballast tanks should be made empty before survey start. (This individually per tank.) Sounding pipes must be intact, free of blockage and readily accessible. 7. Loading/unloading operations should not start until the draught readings and the density readings have been completed. Tank soundings shall be made immediately thereafter. The condition of the ship or the availability of ship's personnel should not interfere with or delay the timely completion of this operation. 8. Notice of readiness will be accepted only when the vessel is ready for a draught survey and complies with the above points and no other conditions may exist on board which will interfere with a timely and accurate draught survey. 9. Officers and crew are requested to offer the surveyor their fullest co-operation in the performance of his duties. 10. Failure to present the vessel in compliance with the required conditions may result in the vessel being placed off-hire and/or being held liable for consequential costs by charterers upon documentary certification of facts and events by an ipdependent marine surveyor. C. Clause in charter party on drayght .yryey Of course, it is advisable to include the basic requirements the vessel has to meet in case of weight determined by draught survey also in charter parties and sales contracts (ships having unsuitable documents may be rejected by charterers). A proposed language of these requirements follows here below: ECE/ENERGY/19 page 41 10. Failure to present the vessel in compliance with the required conditions may result in the vessel being placed off-hire andlor be held liable for consequential costs by charterers upon documentary certification of facts and events by an ipdependent marine surveyor. D. The stevedores and the terminals Stevedores and terminals also have a great interest to know the correct weight of the cargo taken into warehouses and reloaded afterwards. 1. The loaded weight: to be sure no tonnages are loaded in excess. 2. The discharged weight: to be certain that the quantity received as per BIL weight is correct so that they can be sure they will be in a position to redeliver the intaken weight afterwards. That is why it is of prime importance that the stevedores and the terminals allow enough time to the surveyors to properly perform the draught survey, before starting the loading/discharging operations. E. The insurance companies Since many cargoes are insured against weight losses, insurers are of course concerned about shortages being kept to a minimum. F. The administrations In most parts of the world different types of tax, duties, ad valorem dues are assessed on quantities loaded or unloaded. also Governments and other entities of the administrations have a correct determination of loaded or unloaded quantities. fees and Consequently good cause for G. The constant Apart from the above, immediate help to the surveyor, in checking the accuracy of his calculations, can be derived from the constant (see definition in the glossary). When a builder delivers a new ship he must make an accurate assessment of its lightship (i.e. empty) weight. This value is approved by the ship's administration after confirmation by an inclining test. And, since it is important to all future voyage stability calculations, it is listed in the ship's trim and stability booket, a document which is required for all ships by international law. However, after the ship goes into commercial services and the years of operation accrue, the weight which is correctly attributed to "lightship weight" is found to be greater than the lightship weight listed in the trim and stability booklet. This difference is atttibutable to the following items which fluctuate or are, generally, not amenable to precise measurement: ECE/ENERGY/l9 page 42 Commissary stores and crew's personal baggage and stores Thermodynamic deformation (relevant on large hulls) Accumulation of additional equipment, supplies, replaced spare parts which are retained, extra wire rope, cordage, etc. Build-up layers of paint and marine growth on exterior hull Residues of ballast water on boundaries of tanks Mud or scale in ballast tanks The constant has no effect on the accuracy of the weight of the cargo as determined by the draught survey for any single cargo, if it does not change between the start and the finish of surveys. If a good record of the actual constant is maintained over the life of the ship (see page 32) it is very useful in cross-checking the accuracy of the survey. The following check calculation should always be made at the end of the start or the finish survey, whichever is the condition, i.e. before the cargo is loaded or after it has been discharged: ••••••••••••••••• Corrected displacement •••••••.••••••••• -Non-cargo weights (tankage, ballast, etc.) ••••••••••••••••• -Lightship weight (in T & S booklet) ...•...•.•.....•. =Constant If the constant indicated by this check varies by more than plus or minus 10 per cent from the prior history of the cOnstant, it indicates that there may be an error which necessitates that all the readings and c~lculations should be carefully rechecked. ECE/EllEP::;Y Ilj page 43 PART 2. DRAUGHT SURVEY INSTRUMENTS I' l1i I \ I ECE/ENERGY/19 page 44 UN/ECE CODE OF UNIFORM STANDARDS AND PROCEDURES FOR THE PERFORMANCE OF DRAUGHT SURVEYS OF COAL CARGOES PART 2 - DRAUGHT SURVEY INSTRUMENTS REMARKS ON DRAUGHT SURVEY INSTRUMENTS Surely this is an area in which there is a large scope for wiping out obsolete practices, borne throughout decades of individual uncoordinated judgement and adaptation. Each draught surveyor and each corporation specialized in draught survey claims to possess the best design of instruments to cope with the requirements of the job. This is true to some extent but only in the sense that each one of such individuals, one way or another, is carrying out draught surveys having. however, no mirror in which to compare its set of instruments. Time is right for a major reconsideration of all this area and hopefully for the penetration of the modern measurement technology and computerization. Scope exists for introducing new instruments able to perform exactly the following basic functions as listed here below with the goal of gaining speed and attaining a higher level of reliability: (a) An instrument to measure exactly distance, inclinations, and depth. (b) An instrument able to scan exactly the differences of density in a stratification of water from the surface level to the underkeel of the ship depth. (c) An instrument able to measure exactly the volume and the density of liquids contained into a given compartment. (d) An instrument able to measure exactly the volume, net of possible residuals, of a given compartment. (e) An instrument able to measure exactly the volume occupied by the "ship hull" in the water and hopefully also the depth of the immersion of the peripheral line of such mass from the underkeel level. (f) A portable computer easy to utilize and with software specifically created for draught survey. Such an instrument per se would quickly standardize draught survey practices throughout the world. At present mostly the Pacific and Oceanic areas seem to be moving toward this new frontier. Annex A to this book offers an automatic calculation programme connected with the draught survey. However, until such time when the above-described improvement in quality will be accomplished the following equipment can be considered to be necessary for the conduct of draught surveys. EQUIPMENT FOR THE. CONDUCT OF DRAUGHT SURVEYS In order to perform accurate draught surveys the surveyor must equip himself with standard items such as a steel sounding tape, water finding paste or chalk, a powerful flash light, binoculars, calculator, water sampling containers, etc. Some of the typical characteristics of some such instruments are illustrated in the following paragraphs • ...................................................................................................................................................................................................... , " , " " , .. * sseenssssessse , .. ECE/ENERGY/19 page 45 To maintain accuracy in less than ideal conditions the surveyor should further equip himself with specialized items. Conditions that demand extra care and specialized equipment include: Rough seas at the time of reading the draughts Varying densities at different depths and locations of the water in which the vessel floats Different densities in the many ballast tanks due to the vessel ballasting in different geographical locations Tanks, especially full top side tanks, that have sounding pipes flush with the deck. Each of these conditions can hamper the draught surveyor if he does not have equipment that can achieve accurate determination. I. Reading freeboards/draughts - rough seas It is not unusual to find one or two foot seas running along side the vessel being surveyed. Most surveyors have adopted some measuring device that calms the water during measuring. One method that is used with excellent results is a clear, flexible plastic tube of about 6 metres in length with an additional clear rigid plastic tube of about 1 metre and of the same diameter (2 cm) glued to it. Attached to the lower end of the flexible tube there will be a narrow weight (1 kg). The upper end of tube (the rigid part) will be attached to a rope, the tube is submerged in the sea directly in front of the draught marks with approximately 1 meter exposed above water (Fig. 1). The water level within the tube may be seen to rise and fall very slightly, however, with the tube adjacent to draught marks the mean water level can easily be read (this is obviously more practical at the midships mark than at the bow or stern). The water level visible in the tube is unaffected by wave motions and so gives a good reading. Figure 1 I _--- .... i(1 ~. ~ WJ1~'~ / I ·~/·' I " t L,J Mc~l b:nc I \tUl . lV ne:g •• t ECE/ENERGY/19 page 46 DRAUGHT INDICATOR PATTERN developed and patented by: NIPPON KAlJl IENTEl XYOXAI (Japan Marine Surveyors and Sworn Measurers' Association) The drauqht indicator is constructed with the followinq parts: 1. Water-quidinq rubber hose 2. Sinker for water-quidinq rubber hose 3. Draft indicator inner tube 4. Draft indicator protector 5. Protector cap 6. Water level indicator 1. Measurinq line fixing metal 8. Lead weight fixing ring 9. Alighting recognizing rod fixing metal Draft Indicator Pattern Sue Irnf : Otct 11,"'-. ~~----~--~- . , i: <, I I ECE/ENERGY/19 page 47 Description of the parts of the draught indicator: 1. Water-guiding rubber hose Rubber hose: Outer diameter 10 mm (inner diameter about 5 mm) of about ~ 20 feet long will be required. In the port where oil is afloat, rubber is often damaged. Therefore, use vinyl pipe of the same diameter, but in winter time vinyl, is not suitable for use, on account of many cracks due to hardness which may prevent the true indication of water level. Synthetic rubber hose is preferable. 2. Sinker for water-guiding rubber hose In order to sink the rubber hose to the bottom, use the sinker of some steel pipe of sufficient thickness fixed to the lower part of rubber hose. 3. Draft indicator inner tube Outer diameter about 22 mm length about 480 mm transparent vinyl pipe. The lower end connects to water-guiding rubber hose. The water will come into this pipe which is open at the top so as to release the air in the tube. 4. Draft indicator protector Overall length about 550 mm. Main tube made of brass, length about 500 mm, inner diameter 22 mm, having 15 mm wide and about 450 mm long window. Water-guiding rubber hose with sinker and draft indicator inner tube are attached to this protector. 5. Protector cap A device to prevent the entry of water from top of the indicator inner tube and to prevent the separation of each part, and to connect measuring line and water level indicator. 6. Water level indicator Length 470 mm. Width 15 mm and thickness 3 mm made of plastics. In order to indicate the water level, glossy surface was made dull with sand paper. It is inserted in the inner tube and fixed with lower part of the protector cap. 7. Measuring line fixing metal Fixed at the upper part of the cap by means of a screw clamp and connected to end ring of the measuring line. The top of this metal indicates 0 inch, in other words, graduation of measuring line starts there. 8. Lead weight fixing ring Use vinyl insulated telegraphic wire of 3 mm diameter, in order to hang the lead weight to keep the protector upright. ECE/ENERGY/19 page 48 9. Alighting recognizing rod fixing metal When lowering the instrument in the water and looking down from right above, some horizontal mark is required. for which this metal is to be used. For use of the inltrurnent, see the follgwing eXample EXample: From the spot marked with 8 m draught lower the draft indicator with tape line of the length of 1.20 m and suppose that the lower part of the protector has reached the water level. Pick up the draft indicator and look at the water level indicator discoloration and suppose it indicates 17 em. 8.00 m - (1.20 + 0.17) = 6.63 m •••••••. is the reading of draught. Caution for use 1. Keep the stoppers of the cap tight. 2. Once the protector alights on water, you must not raise the measure tape to bring it in line with the datum point on ship's side. You are only allowed to lower it. 3. After taking measurement, you can lower the measuring tape 3 or 4 inches successively, and you can make consecutive measuring three or four times. 4. When the indicator gets wet allover the surface, take it out and wipe down and expose to the wind. Soon the indicator will dry up and can be used for the next service. At night time when you are unable to observe wet part, you may use chalk coating on the surface of indicator plate. 5. After the lower part of the draft indicator alighting on the water, it will take 10 seconds until the water comes inside the inner pipe and comes to standstill. You should allow in any case 15 seconds for water-level settlement. 6. When the water-guiding tube is bent or some inconvenience for the rising of water. ascertain the tubes are all cleared up just tube into water. has a knot, there would be Therefore, it is important to before lowering water-guiding 7. When the tape-line is driven out or curved on windy days and no accuracy is expected, use 3 mm electric cord measure-line instead of the tape-line. If one side of the mid-ship draught mark can be read easily and accurately because it is on the lee side, in certain ports, but only in those ports where temperature remains constantly above freezing, the weather side can be determined by rigging a clear plastic tube filled with water on the ECE/ENERGYl19 page 49 main deck, forming a "U" shape. Running vertlca'l1y down the inside of the port bulwark horizontally across the deck and vertically up the starboard bulwark. The amount of water in the tube is adjusted so that the head of water in the vertical sections (at the bulwarks) can be measured from a fixed point (usually the deck surface) and the difference in height of the water levels is equal to the list. If the tube does not stretch completely from side to side then the horizontal length of the tube actually used can be proportioned to the vessels beam and the list calculated by "similar triangle" calculation, bearing in mind reference points for measuring the head of water in the vertical sectors of the tube should be at equal height above the keel. There will be times when the offshore seas are so rough that reading the offshore draught through a plastic tube is impossible. Presuming that a good (lee) inshore draught is read, an acceptable correction can be made by using a small clear flexible plastic tube approximate length SO m and diameter 1 em. The tube is filled with water, all bubbles removed and stretched athwartship, from top of port rail to starboard rail at approximately midship area. The height of the water level in the tube is measured from the deck, port and starboard at the exact same location. The difference in the water level readings will be the amount of list. 1/2 of this must be added or deducted according to the list, to or from the draught read, and this will be the midship mean draught. Figure 2 :: .:.; ~~ . .. , Notes: 1. Water level at scales must be higher than the deck at the centreline. 2. All air must be excluded from the tube. 3. Zero of both scales must be the same height above the deck line. In cold climatic conditions. however, the instrument (Fig. 2) is difficult to operate and can be replaced by manometers or by instruments like the one patented in Poland and illustrated on later pages. ECE/ENERGY/19 paqe 50 DEVICE FOR SHIP'S "FREE-BOARD" MEASUREMENTS Introduction This instrument has been made through modification of the first one, patented in 1972. All defects were eliminated and there has been made a new apparatus operatinq reqardless of conditions. It had been checked in its final version from 1984 till 1988 making several hundred measurements. Inspections on ships proved that this type of construction had not been found in other harbours. Device features measure "free board" exact to .± 2 film. measurement is unfailinq in each type of wavinq, unless the ship falls to swell (when swellinq, induce regular interval of sound audibility and its fadinq). An accuracy of ± 5 film can be achieved in swell conditions. it eliminates need of overside rope ladder climbing (especially dangerous in winter time). Usinq this instrument measurements are carried out from the deck (safely and cheap). when ship berthinq, 3 em wide slit is enouqh for makinq the measurement. usinq of graduated cable instead of measurinq tape enables to make measurements in wind conditions and ensures long service life of device. in ice conditions, the device lead weight can punch a hole and receive signals from the surface of the water. prompt measurement enables to check ship drauqht durinq the end phase of loading and to stop it in due time. when measurinq on vessels with rounded sheer strake. an arbitrary mark has not to be on deck line but, e.9., on rail. Similar marks may be qraduated on aft and fore body to enable accurate reading of vessel draught in each weather and situation conditions (e.q. roadstead). reel and short sounder make the device easy to be carried in handbaq. ECE/ENERGY/19 page S1 Structure and operation Measuring device consists of: pipe sounder (1) with S meters long rubber hose (2) and sinker (3), deaerating rubber hose (4) (30-40 cm long, placed on the upper part of the sounder). There is an electrode connected by means of measuring cable (5) to electronic system and loudspeaker. graduated cable at 5 em intervals is spooled on the reel (7). When waving use the rubber hose (2) while measurements. In coastal and harbour conditions at 5 meters depth there is constant pressure and thus constant, independent of waving, level of water in the sounder. Either when slight waving or in the ice condition, a sharpened pipe (6) with water inlets is screwed in to enable punching a hole in ice and make a reading of water level. Instruction for use Measurement is made by lowering the apparatus with rubber hose into the water. When receiving the signal, apparatus should be slowly lifted until the signal fades, then make a reading. Sufficient accuracy of measurements is 2-3 mm. ECE/ENERGYI19 page 52 .' '" - _-- ;;-1 - _, I ® -, , ) ~"'-- ./ pipe sounder rubber hose sinker deaerating rubber 5. measuring cable 6. sharpened pipe 7. the reel 8. baffle plate 9. electrode system 1. 2. 3. 4. hose DRAUGHT SURVEY A??ARA7US ECE/ENERGY/19 page 53 In case of out of control signal interfering with the measurements, inside of device ought to be flushed with fresh water and dried up. Sounder is ready for measuring when supply switch on and the short-circuiting switch pressed. In fact there is no need to take care of the apparatus except when the batteries are dead and should be replaced. II. Water @ . I I I I cz:» e-: ~ I I I I i I ""9"" sampling devices: there are devices on the market for sampling liquidS at different depths - they are effective. The following sketches suggest alternative sample devices that have been found useful. Figure 3: is a 4 cm pipe with threaded pipe caps on both ends. Holes are drilled in the top cap. of sufficient size and number, to accommodate a timed descent in the water. Example: If it takes 10 seconds to fill the tube, then the surveyor will time his lowering to the wanted depth to 10 seconds. (This method will give a good mean density from surface to bottom). Cap with holes Figure 4: ~his water sampler can be made of 5 cm clear plastic tubing, with a clapper valve epoxy glued to the bottom, a 1/2 kg, weight is also attached to the bottom of the tube. Attached to the top of tube a loose thin plastic covering in such a way as to permit water to pass out through the top but to restrict water from entering when being pulled up. To recover a water sample, the tube is lowered to a desired depth. Raised and lowered a few times, about one meter at a given depth, to be sure that a good sample has entered the tube. This sample will produce a density only at the level to which it was lowered. Valve Figure 5: when taking samples of ballast water through a sounding tube. this version of the sampler in figure 5 is used. The material should be copper tubing of about 40 cm in length and 2 cm diameter. A valve's device should be fixed in the lower part in a way that when the tubing touches the bottom, the valve opens and water fills in. This sampler is lowered to the bottom of the tank to find the actual density of the water. It is important that the sample be taken inside the tank and not in the higher (upper) part of the sounding pipe in correspondence of the hold, this because the density may very likely vary due to difference in temperatures. ECE/ENERGY/19 page 54 Figure 6: another equipment used to perform a draught survey is the tumble-fill salinometer pot for collection of water samples; Aim: to glean samples of dockwaterlseawater at various specific depths. Descriptions: can with cork which can be removed at desired depth by jerking a cord. Specification: the instruments must be able to obtain a sample at various depths; material: stainless steel; capacity: 1,000 ml; min. height: 400 mm. As alternative to the above, surveyors also use the "zone samplers". In these cans the water continues to flow as long as they are in downward motion and then they close when stopped at a given depth. III. Proving side tanks are full: top side tanks frequently appear to be full, but due to vessels trim and deck camber the forward end of the tanks will frequently have large voids. To prove these tanks are near 100' full, the tanks may be pressed up and forward vents overflowed. If this condition is not observed, it is possible to observe the level of the water in the tank with the use of a 3 cm clear plastic tube approximately 1.5 m in length. One end of the tube will have a glued foam rubber tapered grommet (see Fig. 7). At the instant of removing the sounding cap, the grommetted end of the plastic tube is inserted into the sounding pipe. The ballast might be seen to overflow the top of tube, then drop well down, and in a few seconds stabilize at a steady level. The correct level of the tank is the lowest level reached. &.1: )oc:&:l1: ~~-t7 L-__...!..._-_U figure 7: example Determine height of water in tube or height of water above deck plate required to prove tank is full. L x T = H LBP L = Length of tank T = Trim of vessel (actual trim measured at perpendiculars) LBP = Length between perpendiculars H = Height of water to prove that the tanks are full. ECE/ENERGY/19 page 55 IV. Linear distance measuring devices: serve to measure free board of the vessel at the quayside. for ballast soundings etc. Typical winding-case figure 8: Steel tape measure: surveyors in many parta of the vorld use steel tapes with a T bar or other similar arrangements, at the starting ends, for measuring freeboards. This system has been considered good enough by Board of Trade and Port Authorities. Naturally only professional products should be used, being the liability of the manufacturer to secure calibration of the tape. Each instrument should be accompanied by a calibration certificate issued by an official standards institution. Figure 9: Tank sounding tape: stainless steel tape for ballast soundings, equipped with a bob-weight of a size which will clear the internal diameter of sounding pipes; Aim: to determine fluid height in the ship's tanks. Description: the sounding tape consists of: brass or anodized metal frame with handle; measuring tape fitted with swivel hook or end fittings for dip weight. Specifications: Frame: different types available; can be left at the users' discretion. Tape: minimum length: 2S mm; material: stainless steel; graduated: 1 mm; numerated: 10 mm. Dipweight: material: brass; weight: 400 gr; height: 100 mm; graduated: 1 mm; numerated: 10 mm. Certification: each instrument should be accompanied by a calibration certificate issued by an official standards institution. Typical winding-frame ECE/ENERGY/19 page 56 Cat.No. 15490 ] ! 1.000 s .... .. ... i 05 .. ';: 1010 ~ .. .. • .. !; .. .!: IS ,;. .. .. ~ .. .::: 1020 .. .. -e .. e ... . !: 25 .. - ~ .. ::; 1 030 'i .. .... .. : 35 .. .. ... ... .. 0.990 1.040 .. en . ! ... .. .. Scale (actual size) v. Figure 10: pegsity measuring deyice: to measure density of water and ballast: HYdrometer: reputable glass draught survey hydrometer, measuring density in air in kilograms per litre and certified by an appropriate registered testing laboratory, or which is reqularly checked aqainst a certified hydrometer: ~iml to determine the density of sea/brackish/fresh water. Spec: Zeal draught survey hydrometer or equivalent. materials: suitable transparent qlass . dimensions: overall length: 335 mm app.; diameter 27 mm app. scale: the white paper scale is graduated in density kg/l in air (density in air is sometimes termed apparent density). This permits the weight to be obtained by multiplying the scale reading by the volume in m3 of water displaced • reference temperature: 15° C • poising: shot and black wax • range: 0.990 to 1.040 kg/l (in air). graduated: 0.0005 (0.010 graduations in red). fiqured: O.OOS • surface tension: medium (to be marked on the instrument) • marks: manufacturer'S name or easily identifiable mark • identification number • Certification: each instrument should be accompanied by either a manufacturer's certificate of conformity or a correction certificate issued by an Official Standards Institution. ~t least two instruments with official correction certificates should be available for reference purposes. ECE/ENERGY/19 page 57 INSTRUCTION LEAFLET FOR DRAUGHT SURVEY HYDROMETER for determining the density of sea/fresh water When carrying out a Draught Survey on bulk carrying cargo vessels. it is important that the weight to volume relationship of the supporting water is clearly understood and accurately reported. Most hydrometers at present in use for Draught Surveys are not really suitable for the purpose but ZEAL have designed. in conjunction with S.G.S. Van Bree N.V •• Antwerp. Member of the Societe Generale de Surveillance S.A •• Geneva, this special Draught Survey Hydrometer of the required accuracy, incorporating the following features: A range of 0.990 to 1.040 kg/l suitable for use in sea and fresh water and thus covering the range of densities normally required for Draught Surveys; A scale graduated in density kg!l in air (density in air is sometimes termed apparent density). This permits the weight to be obtained by multiplying the scale reading by the volume in m3 of water displaced; Calibration of the hydrometer for use in sea water, a liquid of medium surface tension; Manufactured from glass, thus permitting certification by the British Standards Institution if required; Alternatively, a ZEAL Certificate of Conformity of test for accuracy against a B.S.I. certified Standard hydrometer can be supplied. INSTRUCTIONS FOR USE 1. A clean, representative sample of the supporting water should be obtained by means of a sampling can or other suitably designed sampling apparatus. (A sample of at least one litre will help to ensure that the temperature and density do not change unduly between collection of sample and taking of readings.) The depth of water in the container must be sufficient to allow at least 25 rom clearance between the bottom of the hydrometer and the bottom of the container. The internal diameter of the container or jar should be at least 50 rom. 2. The number of samples to be taken, also at which depths and at which positions outside the vessel they should be taken. may be important according to the circumstances. 3. Readings may be taken by lowering the hydrometer into a suitably shaped sampling apparatus or by transferring the water to a suitable glass test jar. If a metal or other non-transparent container is used for taking readings ensure that it is full to the brim. If a glass test jar is used, it should preferably be rinsed first with part of the sample so as to avoid undue temperature changes. The container or test jar should be shielded from draughts, which might affect the readings. ECE/ENERGY/l9 page 58 4. The reading must be taken in the sampling apparatus or glass test jar as rapidly as possible. Undue delay in taking the reading could result in temperature changes leading to inaccurate results. In case of doubt, a repeat sample should be taken in order to verify the first observation. 5. Ensure that the stem of the hydrometer and the surface of the water sample are free from grease and oil sinee otherwise the accuracy of the readings could be adversely affected. 6. Hold the hydrometer vertically by the top of the stem and gently lower it into the water sample until it floats freely. 7. Take the hydrometer reading where the level liquid surface meets the graduated scale (see illustration overleaf). CORRECTIONS TO HYDROMETER READING 1. If the instrument is supplied with a B.S.I. Certificate, the appropriate correction should be applied. 2. For most Draught Survey purposes, no further corrections to the readings are needed. A reading is most correct when the glass hydrometer is used at a temperature of 15° C. If immersed in water at temperatures higher or lower than 15° C,the instrument will expand or contract so that, for precise laboratory work, a small correction would be applicable. However, for Draught Survey work, it should be noted that the ship itself will normally expand or contract according to the temperature of the water in which it is floating. The corrections required to compensate for these changes in volume are of opposite sign and tend to compensate for each other. As it is not practicable to calculate any temperature corrections for the ship, for most Draught Survey purposes no correction should be applied for the expansion or contraction of the hydrometer glass. IMPORTANT It is most important to note that the density required for Draught Survey purposes is the average density (in air) of the water in which the ship is floating. Any attempt to correct this water density to density at 15· C, 60° F or some other standard temperature can lead to very serious errors in the weight calculation. ECE/ENERGY/19 page 59 TAKING A READING The line A ----- A indicates the correct reading position at eye level e.g. 1.0285 kg/litre in air. APPENDIX When necessary, a ZEAL Draught Survey hydrometer with a B.S.I. Correction Certificate may be used to verify the accuracy of a brass Loadline hydrometer graduated in Sp.Gr.600 F/600 F in vacuo. If the two instruments are compared in fresh water at a temperature of 15° C or 60° F the following equation applies: (I) Correct reading on glass hydrometer -0.0020 = correct reading on brass Loadline hydrometer. If the comparison has to be made in water at some temperature substantially higher or lower than 150 C, the following corrections should be applied to the readings of the glass and brass instruments before using the equation (1). Water temperature °C Glass Hydrometer Brass Jiydrometer 5 10 15 20 25 30 -0.0003 -0.0001 0.0000 -0.0001 -0.0003 -0.0004 -0.0006 -0.0003 0.0000 -0.0002 -0.0005 -0.0008 ECE/ENERGY/19 page 60 VI. Figure 11: Glass/plexiglass tube: graduated plastic or glass measuring cylinder, of a minimum of 5 cms internal diameter and of sufficient height to contain the hydrometer and allow a clearance between the bottom and the hydrometer of at least 2.5 cms. It must be possible to read the bottom of the " water meniscus at eye level. Density measurements must be taken with the cylinder on a level, stable surface and protected from wind; Aim: for easy and exact reading of the density value: Material: glass or plexiglass. Specifications: diameter: about SO mm; length: 400 mm. VII. Density samples pump: a small pump and plastic tubing or bailing equipment for obtaining the density samples of the ballast tanks via the sounding pipes. VIII. Water sensitive paste: water finding paste for ballast soundings: Aim: to obtain a more accurate reading of the liquid weight. Description: water sensitive or water finding paste is a product which will change colour to f.i. red on contact with water. Consequently when applied on the sounding tape it will allow more accurate reading. IX. Engineers scale: engineers scale for lifting dimensions from vessel's drawings or hydrostatic curves. X. Calculator: with software adequate for collecting primary data and for printing agreed format of survey. XI. Powerful torch: for night hours or dark compartment controls. XII. Binoculars: for reading draught marks. XIII. Conversion factors: for conversion factors, only the appropriate factor listed by the United Nations publication on weights and measures shall be used. EE/Er;c:;;:::;y 113 pa€e 61 PART 3. VESSEL DOCUMENTS I • i\ v '-- I 'I \ r.. ECE/ENERGY/19 page 62 UN/ECE CODE OF UNIFORM STANDARDS AND PROCEDURES FOR THE PERFORMANCE OF DRAUGHT SURVEYS OF COAL CARGOES PART 3 - VESSEL DOCUMENTS GENERAL PRINCIPLES Notwithstanding the personal accuracy of any surveyor the result of a draught survey in the first place depends on the condition of the vessel with regard to her draught marks and possibilities of tank: ballast hold soundings, further on the availability of approved data to derive the corresponding displacement, and last but not least on the quality of the tank soundings and the accuracy of the calibration tables. Based on the above items and in consideration of the fact that a draught survey is usually carried out at both ends of a voyage leg (but seldom by one and the same surveyor), the necessity is quite obvious that both surveyors should perform their survey with the same procedure, using the same weight and measurement units, finding uniform standards of data compilation and documentation on board. 1. Unification of the List of Documents: every bulk carrier has a Trim and Stability booklet, a Load Line document, hydrostatic tables or curves, capacity plan. and tank sounding tables etc. The most recent bulkers also have a computerized program meant primarily to facilitate vessel's master stability calculations and not necessarily useful for draught survey calculations. It is hoped that within a reasonable future shipbuilders will provide new constructions and reclassified vessels with uniform tables, using the metric system as illustrated by the following sections. Such tables should be provided always either in English language only or in mUlti-languages, one of which shall be English, to facilitate worldwide understanding, readability and also usage by computer programs. Furthermore every ship should be furnished by building yards with computerized calculations tools provided the inputs of such programs are approved and certified by the building shipyard and by the Classification Registry of the Ship. Pending such improvement of the vessel documents the reference documents usable in a draught survey are made up of a wide variance of format, precision, and useability of the items. Language other than English also represents a barrier some time and leads to possible mistakes. There is a possibility for a big improvement of the content and the quality of vessel's documents and for prescribing standardized formats requiring Goyernmental Certification of content so as to insure accuracy and consistency. Each vessel needs to be provided with a "Data Manual for Draught Surveys" which is certified by the vessel's home Administration or its classification society. ECE/ENERGY/19 page 63 2. Vessel jnformation: it is the responsibility of the vessel's master to provide the surveyor with accurate and up-to-date hydrostatic information and tank calibration tables for the vessel. which have been certified by the appropriate Government Agency in the country of vessel construction and/or registration. This data in summary should include: The accurate lightship weight of the vessel, including any modifications which have been made. Draught - displacement tables for the vessel; in case of very large or very old vessels one way of upgrading the results should be to use the bonjean data if they are available. Volume and calibration tables for all ballast, fuel tanks and any other compartment, including correction factors for ~ and trim. Unpumpable volumes for all ballast and fuel tanks. In addition it is the master's responsibility to ensure that draught marks are clearly visible at a minimum of six points on the hull, i.e. at the forward, midships and aft positions on the port and starboard sides. Vessel's master should also share with surveyors copy of previous draught surveys from which a diligent surveyor could get quick indications on possible anomalies surfaced also in other ports. The benefit of such cooperation between ship and surveyor would save time, money and unnecessary frictions for all interested parties. It is well known that many old ships do not have the documentation for the draught survey in order. It is suggested that a certain time should be given to the Owners, say one year, to produce the documentation as requested by the final form of draught survey techniques and equipment specifications indicated below. If charterers would include such a prescription in charter parties in their own interest, the issue would find a quick and general answer. 3. The basic document for the performance of draught survey: is the "Data Manual for Draught Surveys" which is certified by the vessel's home Administration or its classification society. The use of the term "approved" documents in the following sections shall be taken to mean that the reference data has been checked by the Administration. a recognized Classification Society. or by the Shipbuilder and that the document available on board has a unique drawing number for identification purposes and; also. bears a stamp or similar endorsement attesting to such verification. The language of the approved documentation shall be in English or, alternatively. all identifications, labels. etc •• facilitating the use of the technical data shall have subtitles in English. ECE/ENERGY/l9 page 64 The weight and measurement units unless there is prior agreement to use different units, shall be in the metric system. The displacement is to be indicated in tonnes equivalent to 1 cubic metre of water at 4° C where the density and the specific gravity is 1.000. As for the sign convention all moments shall be measured from midships. Forward shall be designated (-) and aft shall be desiqnated (+). The thickness of keel plate shall be always included. The bottom of the keel shall be the zero vertical reference on all tables of hydrostatic data. All draught marks must be displayed in centimetres or decimetres at both sides of the vessel, forward, aft and midships. The marks shall consist of numbers 10 cm high with the bottom of the number positioned so as to be the reference mark for the indicated number. The marks shall be placed at every second decimetre and be outlined with a beading of welding or similar, permanent, raised presentation. The range of the marks shall encompass draughts from lightship to the deepest draught permitted by the Load Line assignment with such additional marks, forward and aft, as will encompass the anticipated operational range of trim of the vessel. The approved documentation of the vessel shall include a diagram or a table which furnishes the length between the draught marks and the distances between the draught marks and the adjacent perpendiculars. Forward and aft the draught marks must allow draught readings even if the vessel is extremely trimmed by head or stern. They should be displayed beginning at a draught of 20 cm forward and - depending on LPP - at a reasonable draught aft, and going up to a height of summer draught + LPP/IOO forward and + LPP/20 aft. Even smaller vessels should have midship draught marks. Vessels in excess of 2QQ metres L.O.A. should haye marks provided at five points (forward, end of mid-quarters, midship and aft) on each side, to allow more accurate calculations of hogging Qr sagging. 4. ProvisiQns fQr Sounding Tanks: all tanks for ballast or consumable liquids also on "small" coastal vessels shall have sounding pipes located at the forward and after ends of the tanks. Ballast water tanks in the double bottoms shall have sounding tubes at the forward and after ends of the tanks to permit soundings when pocketing occurs due to trim in either direction. In addition tank sounding and calibration tables should be made in tabular presentation for soundings taken forward and aft, with corrected volumes for each decimetre of sounding and each metre of trim. Linear corrections to soundings should not be presented as they may lead to negative sounding results and do not take "wedge" volumes (dead remains) into consideration. The approved documentation of the vessel shall include a drawing(s), plan and elevation, drawn to a scale appropriate to the length of the vessel but not smaller than 1:200, which locates and identifies every cargo space, tank, cofferdam and void space. The location and length of each sounding pipe shall be shown on this drawing or on a supplementary document. Ballast hold calibration tables should be compiled for soundings and ullages. ECE/ENERGY/19 page 65 Specific notes should be made of the exact location of the reference height of the sounding pipe from where ullages are taken (deck plate or top of sounding pipe) • If soundings are taken, likewise specific note should be made whether soundings are taken to top of DB tanktop or to bottom of bilge: if the latter is the case, additionally height and volume of bilge are to be noted. The range of the trim calibration values for all tanks and ballast holds should be in accordance with the length of the vessel for a trim equivalent to LPP/IOO for forward and LPP/20 for aft. The approved documentation of the vessel shall include tank capacity tables for all ballast and consumable liquid tanks. The tables shall indicate volume in cubic metres versus the sounding or ullage in increments of 10 em. The tables shall be calibrated for zero trim. Additional tables of volumes or tables of corrections to zero trim volumes shall be provided for such other trims, in increments of 1.0 m, forward and aft, to encompass the vessel's intended operational range of trims. It is to be noted that if the trim exceeds this range and the absence of data will prevent accurate calculation, the draught survey cannot be conducted. If the vessel has a duct keel, large bore ballast pipes, or similar appurtenances which, in normal operations mayor may not be flooded, information on the volumes of these spaces shall be included in the approved documentation of the vessel. Surveyors are warned to pay special attention when entering the correction tables particularly in respect of the scale of increments. 5. Verification of Ballast Tank Condition: remaining mud in ballast tanks can lead to considerable inaccuracy in the determination of the ballast weight. There is almost no possibility for the draught surveyor to ascertain the mud in the tanks, either because the tanks are full or the manhole covers are overstowed by cargo. Periodical surveys regarding the class renewal survey anyway. his inspection in order to verify surveyor should be instructed and work. the condition of ballast tanks are part of It would be for the class surveyor to extend mud and sand in ballast tanks as well. The compensated adequately for this troublesome 6. Light Ship Weight: there are different methods in use to determine the light ship weight of a vessel. It is seldom the case that the calculated light ship corresponds to the actual light weight, but such difference forms part of the ship's constant. The "as built" shape normally varies from the design shape and consequently the volume of the underwater body as calculated is only an approximation. ECE/ENERGY/19 page 66 This fact does not lead to any discrepancies between weight loaded and weight discharged as long as this weight is determined at both ends by means of draught surveys. But the weight is wrong by the error of "as built" and it also explains some times the discrepancies between a weight measured by belt weighing and weight determined by a draught survey. There are methods and techniques available today to measure this discrepancy, and such measurements should become compulsory for ships serving in the bulk trade. Furthermore the light ship weight should be approved and verified by the Classification Society and re-approved after the vessel has been in service for 10 years. thereafter every five years, and of course after each modification of the vessel. such as reinforcement of deck stringers, removal or addition of cargo gear etc. Record of ship's constant: the constant is defined as the difference between the lightship weight in the ship's approved Trim and Stability Booklet and the lightship as calculated in a completed draught survey. The vessel is required to keep a "constant" certificate which shows the date, the constant obtained. and the signatures of the chief officer and the surveyor. It shall be the responsibility of the Chief Officer to maintain this record (see remarks on line 090 of Form "Bit). 7. Particulars of Vessel: the vessel's approved documentation shall include the following information: length overall length between perpendiculars extreme breadth moulded breadth depth overall (including keel plate) moulded depth summer draught summer freeboard summer displacement summer deadweight light ship weight. 8. The Required Hydrostatic data: the vessel's approved documentation shall include the following hydrostatic data in tabular form and with the zero reference taken at the bottom of the keel plate: displacement tons per centimetre immersion longitudinal Centre of Flotation moment to trim one centimetre. The range of the hydrostatic data shall be from the light ship draught to the deepest draught permitted by the Load Line assignment. ECE/ENERGY/19 page 67 9. pisplacement: the approved documentation of the vessel shall include tables furnishing displacements in metric tons of fresh water for every 20 rom from the light weight draught to the deepest draught permitted by the Load Line assignment. These tables shall provide data for zero trim and for such other trims, in increments of 0.5 m, or less, forward and aft, as will encompass the intended operational range of trims. It is to be noted that draught surveys cannot be conducted when the trim exceeds this range. The displacement data shall be generated by integration of the Lines drawing at the various trims tabulated and shall include the shell plating and the appendages. The displacement at trims other than zero may be calculated by formula but this shall include both the LeF and the Hemoto corrections. 10. Summary of the required documents: for an accurate draught survey it can be considered that the following items are mandatory requirements: sign convention; draught readings from below keel; raised draught marks up to LPP/IOO fwd, LPP/20 aft; proper tank sounding conditions; verification of light weight: particulars of vessel as previously listed; distance between draught marks and perpendiculars; length between draught marks fore and aft; displacement tables corrected for trim in FW; tanks sounding tables in tabular presentation of volumes; trim correction tables with corrected values for each decimetre of sounding and each 0.5 m of trim; range of calibration tables for a trim of forward LPP/IOO aft, LPP/20i identification plan for: each tank and ballast hold; each cofferdam and void space; with capacity tables for: each ballast tunnel/duck keel and; large bore ballast pipes. 11. Fipal observations: as long as no respected international standards are applicable, Yards and Owners will continue to supply just the minimum of information on the vessel, using their own standard and opinion about measurements units, signs, volume moulded or on shell sides, arrangement of sounding pipes etc. Since the inaccuracy of documents (like for instance approximate tank calibration) could affect also the seaworthiness of the ships. IeMpO. and Classification Registry should revise their rules in this matter and proceed in turn to the verification of the existing vessels when they will be due for Class Survey. The Solas convention should help indirectly the situation within 1993. Especially light ship weight is a figure in regard to which Yard and Owners tend to have different views although they aim for the same target: to achieve the maximum dead weight capacity at a minimum of expense. In the market, this can become a question of compatibility and competition and exceptions are made if standards are not mandatory. ECE/ENERGY/19 page 69 r ! I I I i I I PART 4. SURVEYORS' QUALIFICATIONS ECE/ENERGY/19 page 70 UN/ECE CODE OF UNIFORM STANDARDS AND PROCEDURES FOR THE PERFORMANCE OF DRAUGHT SURVEYS OF COAL CARGOES PART 4 - SURVEYORS' QUALIFICATIONS GENERAL PROBLEMS There is no standard for draught survey execution contrary. for instance, to the drawing up of the ship's data (draughtmanship, diagrams etc.). Also a reference can be made to the IMO Conventions. on Load Lines (1966). When calculating the vessel's displacement (e.g. at the inclining test) Classification Societies and Shipping Inspectorates stick to this Convention. For draught survey instead the surveyors are actually at total liberty to set their own standards. Every Sworn Surveyor in the countries where certification exists has to make a pledge to carry out his duties "to his best skill and knowledge like a good and true draught surveyor", Unfortunately standards or agreements on draught survey methods that may be referred to are still lacking, rendering trading partners strongly dependent on the integrity and skill of the surveyor. The world over there is excessive diversity in the way draught surveys are carried out leading to a great deal of uncertainty for buyers, sellers and carriers of cargo. Obviously each surveyor regards himself as an expert in his field employing standards of his own (individual subjective interpretation) which may deviate from the standards used by his colleague at the other side. If the trading partners are lucky, surveyors at either side agree upon a certain working code in order to reduce discrepancies caused by the different methods used (collective subjective interpretation). The lack of draught survey uniformity tends to generate numerous complaints by Principals, the weak legal evidence of the draught survey report and the lack of an authorized training or certification scheme are other difficiencies, The qualifications and experience of the draught surveyor is considered to be of paramount importance. Frequently, surveys must be conducted under time constraints or adverse conditions of sea and/or weather. Also, the format and content of the ship's technical data varies widely and special expertise is needed to use this information correctly. It is believed that quite often cases of dispute over cargo weights can be attributed to a lack of experience on the part of the draught surveyor. In other cases, the difficulty may be caused by deficiencies in the ship's data. The expertise of the draught surveyor will depend upon his training, professional development and subsequent 4xperience. While a background as a deck officer on a merchant ship has been, and will probably continue to be, the principal prerequisite for the draught survey profession, non-seafaring persons can function satisfactorily in this profession provided they obtain sufficient instruction. This Code will meet a need by supplying a text book which, augmented by on-the-job training, could constitute such instruction. ECE/ENERGY/10 page 71 SPECIFIC CONSIDERATIONS AND LIMITATIONS At present, in most countries, there is no governmental certification of draught surveyors. So the choice of the surveyor by the client must be on the basis of his reputation. Most of the major organizations specialized in the draught survey activity recognize the importance of maintaining their reputation and, therefore, demand the highest standard of character and integrity in selecting their employees. Eyentually, there shQuld be an International Scheme for Licensing the Surveyors set for instance by the ILO. Only requiring a certificate from a school would probably not address the problem. Surveyors should be taken from the rank of experienced seamen possibly holding licences no less than first mate certificate and subsequently be trained on the job. As for the importance of nautical-related activities, there is a difference between nautical and engineering disciplines. In the former case the deck officer is concerned with operating the ship at sea and in port. Engineers and naval architects operate in a world of structures and materials which can be measured and costed. They are practising established disciplines linked particularly, as far as ships are concerned, to standards created by Governments and Classification Societies that define strength, durability, maritime fitness, etc. Nautical-related activities instead, are more sporadic and create less predictable demands which are, by their nature, Challenging. They do, however, require experience for their solution. As opposed to engineer surveyors, who are devoting their talents and skills to what is basically another diversification of their primary career, the draught surveyor is in essence starting a second career and coming from a shipboard environment, may find it somewhat difficult to find his way around shore-based institutions and practices. This is why proper training is a must. Draught surveys will involve the surveyor in the measurement of a wide variety of different types of vessels and of different nationalities each with its own characteristics. Furthermore. measurements may sometimes have to be made in difficult circumstances so that no draught survey manual could endeavour to cover all possibilities. Because of the above peculiarities all draught surveys should be conducted by an accredited and experienced marine surveyor as experience in this area will assist in alerting him to any deficiencies in vessel equipment or hydrostatic data and to the effect of any modification to the vessel which may influence the accuracy of the survey. It may appear that the draught survey accuracy entirely depends upon the skill and the integrity of the surveyor/expert. Yet, however skilled the surveyor may be, without the required data and the cooperation of the partners concerned. he will not be able to effectively prevent weight disputes, nor will he be able to effectively resolve such disputes as may arise. ECE/ENERGY/19 page 72 Skilled or not, figures will always be arrived at in one way or another, but whether or not this represents the correct weight will remain an open point of dispute so long as those directly involved (the buyer, the seller, the carrier and the cargo or transport underwriter) remain devoid of the understanding of how their cargo values are ascertained. Only they, and they alone, are capable of enhancing the reliability of the draught survey by exerting their influence when concluding their agreements of sale, charter and selection of draught surveyors. It goes without saying that unscrupulous andlor unqualified individuals in this discipline, like in other fields of activity, can be hired for very low fees and cause large economic damages. This is why it is advisable to reward adequately the surveyors. In terms of high level education the surveyor should have satisfactorily completed two years of College or University or demonstrated an equivalent level of education as evidenced by possessing not less than a first mate (chief officer) licence in the merchant marine or equivalent. This qualification is intended primarily to establish that the person has the mental capability to satisfactorily carry out the tasks required by a draught surveyor. In terms of training prior to commencing work as a surveyor, the person should have a minimum of five years' experience in work on board ship either in seagoing operations or port cargo operations. This experience is intended to ensure that the person has a good knowledge of the layout of a ship, especially its cargo holds and tanks, the general working of a ship, and the hierarchy of the personnel involved in the operation of a ship. Many surveyors have a nautical background during which they have been sufficiently trained in practice. Another way to acquire the necessary training is to join one of the special training courses, such as given by international corporations specialized in draught survey. Prior to commencing work as a fully qualified draught surveyor. any person, including licensed merchant marine officers and persons with extensive maritime experience, shall undergo at least three months on-the-jOb training by accompanying a fully qualified surveyor engaged in the performance of draught surveys. This training shall include participation in not less than 50 complete draught surveys. The training shall ccver, in detail, the subjects of acquisition of pertinent ship and cargo inform~tion. recording of draughts, determination of water density, sounding of tanks, calculations, and preparation of reports. In terms of temperament, in so far as it can be evaluated, the surveyor should have the ability to work under pressure because ship operations or cargo operations often must await the completion of his tasks. Also, he should be tactful and able to work well with people because the expeditious completion of his task often depends upon the cooperation of personnel who are not within his charge. During the daily draught survey work a good deal of climbing of ladders and walking is involved. Consequently the need of good physical health is self-evident. ECE/ENERGY/19 page 73 Last, but not least, in terms of character, because most of the component tasks which constitute a draught survey cannot be directly supervised and, because the draught surveyor must prepare his report on the basis of fact and without prejudice or favour to his client, or to any other party, it is of fundamental importance that the surveyor must not have a criminal record or any other blemish of his personal reputation which may indicate that he does not possess the highest standard of character and integrity. In view of the complexities listed in the previous paragraphs and the necessary accuracy for the proper performance of a draught survey, it is axiomatic that the persons so engaged be of "proven ability" by which is meant in summary: (a) An unblemished reputation attesting to his honesty and integrity. (b) Total cognizance of shipboard terminology as it pertains to draught surveying practice. (c) Knowledge of the principles of hydrophysics combined with sufficient familiarity with basic naval architecture to describe the basis for each of the steps necessary to accurately ascertain by draught survey procedure the amount of cargo loaded or discharged. (d) Sufficient experience on board vessels of differing propulsion system and varying tankage arrangements to ensure that the survey includes all data necessary to a complete calculation. This shall include, necessarily, the ability to accurately interpret a vessel's plans and documents though they may be completed in a language alien to the draught surveyor. (e) An understanding of mathematics sufficient to the performance of the calculations. (f) A facility with items (b)-(e) above, taken in combination, sufficient to obtain such further information pertinent to the vessel, from the deck or engine personnel, as is necessary to the proper completion of the survey, should the need arise. (g) Good command of the English language, and the ability to use modern computers and electronic instrumentation. : ECE/ENERGY/19 page 75 PART 5. GLOSSARY OF TERMS AND DEFINITIONS ECE/ENERGY/l9 page 76 UN/ECE CODE OF UNIFORM STANDARDS AND PROCEDURES FOR THE PERFORMANCE OF DRAUGHT SURVEYS OF COAL CARGOES PART 5 - GLOSSARY OF TERMS AND DEFINITIONS Terms used in this document in connection with draught survey terminology and also terms typical of shipping, chartering and trading glossary are defined here for the benefit of the reader and user. Administration Means the Governments of the State whose flag the ship is flying. Adopted The action of IMO or ILO or other international organization in approving any set of rules to be submitted to governments for possible ratification. Aft At or towards the rear part of the vessel. Aft draught (AD) Draught, measured at the aft part of the vesseL Aft perpendicular (AP) See perpendiculars Aft peak tank A compartment situated at the extreme rear of the vessel often used to contain fresh water or ballast water. Age of a ship Means the elapsed period of time determined from the year of build as indicated on the ship's registry papers. Air draught A vessel's air draught is the height of the uppermost part of the ship (top of mast) above the waterline. Usually given to ascertain the ship's clearance under bridges or loading/discharge machinery. All ships Both "new" and "existing" ships. Amidships (midships) Amidships is to be taken as the middle of the Rule length, L, measuring from the forward side of the stem. (See also rule length and midships). Angle of repose The maximum slope anqle of non-cohesive (i.e. free-flowing) granular material. It is the angle between a horizontal plane and the cone slope of such material. AP Application of corrections in calculations Area and moment of area Back Cargo ECE/ENERGY/19 page 77 angles of repose A low angle of repose characterizes a bulk cargo which is particularly liable to dry surface movement aboard ship. (See also cargoes which may liquefy and flow state). Aft perpendicular. The following corrections must be made: 1. Perpendicular corrections to draught readings. 2. Nos. 1 and 2 trim corrections. 3. Hydrometer stem correction (if given). 4. Seawater density corrections. 5. Water tank trim and list corrections. 6. Ballast water density correction. 7. Fuel tank temperature corrections if temperature changes are large. 8. Alterations in bunker, lubricating oil and stores. If any corrections cannot be applied, this fact should be noted in the report. Nautical surveyors of whatever discipline are constantly required to find the area, the moment of area and the second moment of area of figures bounded by straight lines and curves. In the case of ships, the curves will generally be fair and smooth. If the ordinates defining a particular curve represent areas, then the area under the curve will be a volume and if required the centre of gravity of the volume can readily be found. Cargo loaded on what would have otherwise been a return ballast leg is known as back cargo. The term usually applies to the cargo carried back to ECE/ENERGY/19 page 78 the vicinity of the loading port of the principal (outward) cargo. Partial back cargoes are also common. Back haul The return voyage with or without back cargo. Back-to-back Charter A charter arrangement with a shipowner that guarantees cargo for a given period against a shipbuilding contract. Ballast Water, river water or sea water, pumped into the appropriate tanks or out of the vessel in order to adjust the trim or draught of the Ship. To provide stability and propeller immersion. Ballast tanks Tanks specially designed aboard the ship to receive water ballast or, in the case of tank vessels, cargo tanks used to contain ballast. Bareboat Charter An agreement whereby the charterer assumes responsibility for virtually the complete management of the vessel and for all relateQ expenses including the hiring of crew, maintenance and repairs. Beam (breadth) Breadth of the ship is the extreme width from outside of frame to outside of frame at or below the deepest subdivision load line. Bilges Spaces at the bottom of the engine room or pump rooms where water is allowed to accumulate. As the bilges usually also contain waste oil. they may not be discharged within port limits. For draught survey purposes the quantity of liquid in the bilges should be controlled before and after loading or discharge, so that any change in quantity can be detected. Block coefficient (Cb) The block coefficient, Cb, is the moulded block coefficient at draught T corresponding to summer load waterline, based on Rule length L and moulded breadth B, as follows: moulded displ. (m3) at draught T Cb = LBT Blocked sounding pipes Boiler feedwater tanks Bonjean curves Boundary curve and parabolic curve ECE/ENERGY/19 page 79 If a sounding tape cannot reach the bottom of the pipe, any reading will be in error. The maximum possible soundings, as shown in the tank calibration tables should be checked at intervals by the ship's personnel and checks should be made at a draught survey. Tanks provided aboard the vessel to contain water used for the production of steam. The area of a transverse section of a ship to successive waterlines may be calculated and plotted in the form of a fair curve known as a Bonjean curve (named after the Frenchman who first used them). The curves are often plotted on a profile of the ship as shown, and this enables the volume of displacement and centre of buoyancy to be calculated to any waterline, trimmed or even keel. The curves are particularly useful for stability, strength, capacity and launching calculations. The curves may also be plotted using a vertical line as a common base. This has advantage that larger scales may be used for the areas of the sections, but if the ship is trimmed it is necessary to obtain the draught at each of the displacement stations before being able to read off the values of the areas. If the equation of the boundry curve were known then the area under the curve could be found quickly and accurately using the appropriate mathematical formula for integration. In the majority of cases, however, the equations are not known and it is generally assumed that the curved boundaries consist of a series of parabolic curves. This enables approximate arithmetical, rather than mathematical, rules to be applied to calculate the areas and moments of areas about a particular axis. The values so obtained are normally sufficiently accurate for the great ECE/ENERGY/19 page 80 majority of practical purposes. Any errors which may remain after taking appropriate steps are of the order of less than 1/4 per cent of the area which would be obtained using mathematical processes if this were possible. Breadth (beam) Breadth of the ship is the extreme width from outside of frame to outside of frame at or below the deepest subdivision load line. Bulk carrier A vessel designed for the carriage of bulk cargoes in dry form. Bulkhead deck Bulkhead deck is the uppermost deck up to which the transverse watertight bulkheads are carried. Bunkers The fuel used by a vessel. (See also fuel oil and oil fuel). Bunker surveys Any survey to establish the quantity, and in some instances the quality, of the oil, fuel and fresh water remaining on board a vessel. Bunker tanks Tanks intended to contain fuel oil either for steam raising purposes or for the provision of power to the main engines and auxiliaries. Calibration tables See tank sounding tables. Cape Size A class of vessel which, for the purposes of this Code, is taken to be in the range of 80,000-160,000 dwt in size. The term describes a vessel size that is too large for the Panama Canal and must navigate the Cape of Good Hope. Captive fleet A group of vessels owned andlor operated under the direct control of either a raw material seller or buyer. Cargo guarantee The guarantee given to a shipowner by a raw material buyer or seller that he will provide cargo for a certain period of time. Cargoes which may liquefy Cargo space C & F Centre of buoyancy (B) Centre of flotation (F) Centre of gravity (G) Centre tank Check of void spaces ECE/ENERGY/19 page 81 Materials which are subject to moisture migration and subsequent liquefaction if shipped with a moisture content in excess of the transportable moisture limit. (See also Angle of repose and flow state) Any space in the ship appropriated for the carriage of cargo. Cost and Freight. The seller must pay the costs and freight necessary to bring the goods to the named destination but the risk of loss or damage to the goods, as well as any cost increases, is transferred from the seller to the buyer when the goods pass the ship's rail in the port of shipment. The centre of gravity (B) of the volume formerly occupied by the fluid displaced by a floating body. Centre of displacement. The pOint around which a ship tips often called the "tipping centre" (F). This is the centre of gravity of the area, or centroid, of the waterplane of a ship. For small angles of trim consecutive water-lines pass through F. This is the point through which the total weight of the ship may be assumed to act. It is also defined by: (a) KG the vertical distance above the base. (b) FG the longitudinal distance from the forward perpendicular. (c) LCG the longitudinal distance from amidships. Means any tank inboard of a longitudinal bulkhead. Check soundings should be made of all void tanks/spaces, i.e. duct keel, chain locker, hold bilges, engine room bilge, cofferdams, saddle tanks, etc. ECE/ENERGY/19 page 82 CIF Cost, Insurance and Freight. This refers to the cost of a commodity, its insurance and cost of transporting by sea to a specified port, all borne by the seller. It should be noted that the seller is only required to cover insurance on certain minimum conditions. Clean Ballast Clean ballast means the ballast in a tank which since oil was last carried therein, has been so cleaned that effluent therefrom if it were discharged from a ship which is stationary into clean calm water on a clear day would not produce visible traces of oil on the surface of the water or on adjoining shorelines. C.O.A. Contract of Affreightment. This is a transportation contract between a charterer and a shipowner which is fixed on the basis of cargo quantity or consecutive voyages, and usually covers a long term period. A specific vessel mayor may not be nominated to perform the task. Coefficients of form Form is used as a general term to describe the shape of a ship's hull as defined by the lines plan. To compare one ship with another a number of coefficients are used. These may be obtained by calculation and are of value when making power, stability, strength, tonnage and other design calculations. Cofferdams fwd and aft These terms apply more particularly to ocean tankers, coastal tankers and tank barges. They are empty spaces provided in order to separate the cargo tanks from the machinery space aft and from the forward peak and other forward parts of the ship. Cofferdams are also on O.B.O. between each hold. Cofferdams frequently contain water, intentionally or accidentally, and should therefore always be sounded both before and after cargo is being measured by draught survey. Combination carrier Computers Concentrates Condition survey (vessel suitability to draught surveys) Constant ECE/ENERGY/19 page 83 Combination carrier means a ship designed to carry either oil or solid cargoes in bulk. Modern draught surveyors now can make extensive use of computers. which because of their high-speed number-handling capabilities take much of the tedium out of the basic calculations. The software programs use simple and multiple arithmetical calculations and are based on the principles outlined in previous sections. For a ship the input data are generally the offsets of the ship as measured from the waterlines or body plan. Separate programs are available from many commercial sources and can be used on small or large computers. Materials obtained from a natural ore by a process of purification by physical or chemical separation and removal of unwanted constituents. A survey of a vessel and of the equipment on board to establish the condition and perhaps fitness to trade of the vessel and to draught survey control. To be required by charterers prior to a vessel being chartered or at regular intervals. Charterers intending to use a ship also for cargo weights determination should require also the survey of the vessel's documents including data specifically needed and issued for draught survey and calibration manual to be issued upon request by classification registry. The difference between the light ship weight according to ship's documents and the net empty survey displacement after deducting all measurable weights. The weight of a completely empty ship (light weight) is known from the builders data, as used for the inclining experiment. The variable weights. i.e. fuel, ballast water, ECE/ENERGY/19 page 84 fresh water, lubricating oil stores, etc. can be calculated by measuring those items. This is particularly true of liquids, providing the relevant tank has been calibrated. The total of the above known weights is normally less than the weight given by the displacement calculation for the particular draught. The difference is termed the constant for the vessel at that time. The constant will vary, depending On which items in a particular draught survey are considered to be fixed. It will include cooling water in the engine systems, lubricating oil in engine sumps, etc. but it may also include all lubricating oil andlor permanently filled water tanks. The constant should vary over consecutive surveys only by approximately plus or minus 10 per cent. Variations greater than this should be identifiable by differences in the items used to obtain the deductions mentioned in the first paragraph above. The more items which have their weights calculated in a particular survey, the smaller and more accurate the constant will be. The total of all known weights, plus the constant, is subtracted from the loaded displacement to obtain the weight of cargo on board. Dead freight Damages payable to the shipowners as a result of loading a vessel to less than the agreed limits. Dead Remains in Tanks Another source of error is the fact that it is almost impossible to empty each tank completely. Although this is unimportant for fuel oil tanks - the remaining fuel in the tanks will be included in the constant - it may cause important errors in the determination of the ballast figure. It is very difficult to trace and include in the dead weight calculation remaining "wedges" in ballast tanks, if the vessel's trim is contrary to the position of the sounding pipes, unless there are sounding pipes at both ends of the tank. ECE/ENERGY/19 page 85 In addition the calibration tables have to be made in computed values for various trim conditions. Linear corrections may lead to negative soundings results and should not be accepted. Deadweight (DW) Means the difference in metric tons between the displacement of a ship in water of a specific gravity of 1.025 at the load waterline corresponding to the assigned summer freeboard and the lightweight of the ship. Deckline A line clearly marked on the Port and Starboard sides of the vessel, amidships as required by International Loadline Regulations. Deepest subdivision load line The waterline which corresponds to the greatest draught permitted by the subdivision requirements which are applicable, or by Load Line Convention requirements. Deeptanks Portions of a vessel's hold partitioned off and specially constructed to carry water ballast and also arranged to carry dry or liquid cargo alternatively. The usual plan is to have deep tanks at either or both ends of the engine and boiler space, extending from side to side of the vessel, but they are occasionally fitted in the wings only. The purpose of deep tanks is to provide additional ballast without unduly lowering the centre of gravity in large modern cargo vessels of bluff form, where double bottoms do not afford the necessary amount of ballast. They are bounded at each end by reinforced watertight bulkheads, and at the top by a watertight steel deck or flat. They usually run from the tank top up to or above the lower deck. Density (apparent) The apparent density of sea water, fresh water, ballast water, etc. is measured by the Draft Survey Hydrometer and gives weights comparable to those which would be obtained by weighing a ECE/ENERGY/19 page 86 carefully calibrated container on an accurate weighbridge, so as to obtain commercial weights. (See also specific gravity). Density (true) The mass per unit volume of a substance. Density of ballast water The density of the ballast should be measured in as many tanks as necessary in order to obtain a true figure. It may be that different tanks will have different densities, if ballast has been loaded at different places. Differences may also occur if the ballast was taken in a river port, with tidal changes. Depth (D) Depth, CD}, is measured. in metres, at the middle of the length, L, from top of keel to top of the deck beam at side on the uppermost continuous deck. When a rounded gunwale is arranged, the depth (D) is to be measured to the continuation of the moulded deck line. Diesel oil Fuel oil used to feed diesel engines. There are various grades of diesel oil including light diesel oil for auxiliary engines and heavier diesel oil for main engines. Displacement as a volume This is the volume of the depression in the water occupied by the ship, measured in cubic metres. Displacement as a mass This equals the quantity of water displaced and as the kilogram is the unit of mass and 1,000 kg = 1 tonne, the unit which is used when referring to the size of a ship is the tonne. Displacement as a weight This is the weight of water displaced by the ship and equals the volume displaced multiplied by a constant representing the density of water i.e., In fresh water 1,000 kg/m3 In sea water 1,025 kg/m3 The displacement weight of a ship can vary according to circumstances and position in the world. although displacement weight and ship weight are equal when the ship is at rest in equilibrium in still water. ECE/ENERGY/19 page 87 Displacement and hydrostatic information If the displacement for mean draught is given in cubic metres, this figure should always be used in conjunction with the observed apparent seawater density to obtain the weight of the ship at a given moment. This will be a weight in air. If the displacement is given in tons or tonnes the conversion factor applied to the volume should be obtained from the hydrostatic information. If it states that an "S.G" or "density" of 1.025 has been used then the given displacement should be converted back to cubic metres for multiplication by the apparent seawater density. This will ensure that all weights are weights in air not weights in vacuo. Displacement and tonnage Are among the terms most widely used when considering ships and shipping and although there are different types of displacements and tonnages they are all related basically to the total volume or partial volume of the ship. Displacement extreme This equals the moulded displacement, plus the displacement of the shell plating, bossings, cruiser stern and all other appendages. Displacement moulded This is the mass of water which would be displaced by the moulded lines of the ship when floating at the designed load water-line. Displacement table A table, specially prepared by the building shipyard for each vessel, giving the displacement corresponding to various draughts. The half-breadths of the moulded waterplanes are measured from the body plan and put into table. The displacement is found by summing the areas in two directions - i.e. vertically and horizontally - and of course the two answers must agree. Double bottom tanks Tanks situated in the vessel's double bottom and used either for bunkers or ballast water. ECE/ENERGY/19 page 88 Draught (draft) Draught is the vertical distance from the moulded base line amidships to the subdivision load line in question. Draught marks A series of figures painted or welded on the vessel's hull. usually forward, midships and aft, on both Port and Starboard sides and indicating the draught of the vessel at the points where the draught marks are situated. Draught survey A system of measurement of cargo weight based on measuring the draught of the vessel before and after loading or discharge, taking into account any changes in weight other than cargo, which may have taken place during the cargo handling operation, i.e. changes in the weight of water ballast, bunkers, stores, etc. Drinkable water Fresh water for human consumption. Potable water. DWT See deadweight ECE Economic Commission for Europe of the United Nations Engine water Water used for the cooling system of diesel engines. ECOSOC Economic and Social Council of the United Nations. Even keel When the forward and aft draughts of a vessel are identical, the ship is said to be on an "even keel", Expert A person with special skills, technical knowledge or professional qualifications whose opinion on any matter within his cognizance is accepted as evidence. The decision as to the qualification of a witness to give evidence as an expert is made by the judge or arbitrators, Filled compartment The term "filled compartment" refers to any compartment in which after loading and trimming as required the ballast water or cargo in bulk are at their highest possible level. ECE/ENERGY/l9 page 89 Flag of registry The country in which a vessel is registered. Flag state The country of the flag the ship is entitled to fly. The State having jurisdiction over that ship. Flow moisture point The percentage moisture content (wet mass basis) at which a flow state develops under the prescribed method of test in a representative sample of the material. (See also Flow state). Flow state A state that occurs when a mass of granular material is saturated with liquid to an extent that under the influence of prevailing external forces such as vibration, impact or ship's motion, it loses its internal shear strength and behaves as a liquid. (See also Angle of repose, Cargoes which may liquefy and Moisture migration). F.I.O. Free In, Out and Stowed. Loading, stowing and discharge which is free to the shipowner. F.O.B. Free on Board. Buyer of cargo arranges the shipping and pays for insurance and freight over and above price of the commodity. F.O.C. Flag of Convenience. Used to denote the registration of a vessel in a country that does not require its nationals to be necessarily involved in the ownership or operation of a vessel. Fore (forward) At or towards the front part of the vessel. Forepeak tank A compartment situated at the extreme forward part of the vessel often used to contain fresh water or ballast water. Forward draught (FD) Draught, measured at the forward part of the vessel. Forward perpendicular See perpendiculars. FP Forward perpendicular. ECE/ENERGY/l9 page 90 Freeboard Deck The freeboard deck is normally the uppermost complete deck exposed to weather and sea, which has permanent means of closing all openings in the weather part thereof, and below which all openings in the sides of the ship are fitted with permament means of watertight closing. Freeboard (assigned or statutory) The free board assigned is the distance measured vertically downwards amidships from the upper edge of the deck line to the upper edge of the related load line. Fresh water For the purpose of draught survey measurement of "deductible liquids", fresh water may be defined as the total of the drinkable water and washing water aboard the vessel. Fuel oil (heavy) High density fuel oil used either as boiler fuel or as fuel for main diesel engines suitably adapted for the purpose. (See also Bunkers and Oil fuel). General cargo vessel A vessel of the single deck type, or a vessel having one or more "tweendecks" whose holds run without interruption from shell plating to shell plating or a vessel whose hold subdivision by longitudinal bulkheads is insufficient to effectively restrain the bulk cargo from shifts capable of imperilling stability and without special strengthening for heavy cargo. Handy size A class of vessels which, for the purposes of this Code, is taken to be under 50,000 dwt in size. Hogging The deflection of a vessel loaded in such manner that the draught amidships is less than the mean of the forward and aft draughts. Hydrostatic curves A document specially prepared for each vessel indicating, among other things, the centre of flotation or "tipping centre" at various draughts. Sometimes referred to as "curves of form", More From This UserSkip carousel Hotspot Cold ChainBeacon 204Port Cities Mersin Global Terminal Operators 201250 Container Ports 2012 Hanne Danica Accident Report Resume Steel Pre-Loading Survey at CHINARisk Watch Vol 09 2Mars 245 - March 2013Bulk Liquid Cargo Contamination - Prevention and ResponseMitigation - Minimising the Loss in Case of Liquid Cargo ContaminationMaritime Clipping News 164-13-06-2013Maritime Clipping News 162-11-06-2013Maritime Clipping News 163-12-06-2013Maritime Clipping news 161-10-06-2013Mars 246 - April 2013Accident Pcc Vega LeaderMaritime News 152-01-06-2013Maritime Clipping News 153-02-06-2013Mars 245 - March 2013MARS 243 January 2013MARS 241 November 2012MARS 239 - September 2012Zim Container GuideMARS 238 - August 2012 - Sign up to vote on this titleUsefulNot usefulDraught Survey by scdl1310.0 (0)EmbedDownloadRead on Scribd mobile: iPhone, iPad and Android.Copyright: Attribution Non-Commercial (BY-NC)List price: $0.00Download as PDF or read online from ScribdFlag for inappropriate contentMore informationShow less
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