Hasarsız stabilite kriterlerinin karşılaştırmalı değerlendirilmesi
Comparative evaluation of the intact stability criteria
Yazar: CANER BAKAR
Danışman: PROF. DR. METİN TAYLAN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Gemi İnşaatı ve Gemi Makineleri Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2015
Konu: Gemi Mühendisliği = Marine Engineering
Dizin: Askeri gemiler = Naval ships ; Karşılaştırmalı değerlendirme = Comparative evaluation ; Savaş gemileri = Naval ships ; Statik stabilite = Static stability ; Yük gemileri = Cargo vessels ; Çoklu karşılaştırma teknikleri = Multiplecomparison techniques

Özet:
Günümüzde ticari gemilere uygulanan stabilite kriterlerinin gelişim süreci eski
tarihlere dayanmasına rağmen, bunun yazılı kural haline getirilmesi 1960'lı yıllarda
olmuştur. Gemilerde ilk resmi Uluslararası stabilite kuralları IMO (International
Maritime Organization) A.167 önergesiyle 1968 yılında uygulanmaya başlanmıştır.
Temel olarak bu önerge, gemilerin başlangıç metasantr yüksekliği ve doğrultucu
moment kolu eğrisi altında kalan alan değerleri için bazı kriterleri içermekteydi.
Gemilere etki eden dış unsurlarla ilgili herhangi bir parametre dikkate alınmamakta
idi. Bundan dolayı, IMO 1985 yılında A.562 önergesiyle, gemilerin yalpa ve rüzgarın
bileşik etkisi altındaki durumunu inceleyen hava kriterini yürürlüğe koymuştur. 1993
yılında ise daha önceki önergeleri A.749 önergesinde toplayarak, bu kriterlerin, 24
metre ve daha büyük tüm gemilere uygulanmasını zorunlu hale getirmiş ve daha
önceki önergeleri yürürlükten kaldırmıştır. Daha sonra, A.749 önergesi 1998 yılında
"Intact Stability (IS) Code" (Hasarsız Stabilite Kodu) olarak güncellenmiş ve 2008
yılında nihai halini almıştır.
Ancak askeri gemilerde, ticari gemilerde olduğu gibi uluslararası kabul görmüş ve
bütün ülkelerin kullandığı kurallar bulunmamaktadır. Genellikle ülkelerin kendi
donanmalarına ait kullandığı kurallar bulunmaktadır. Ancak, birçok ülkenin askeri
gemi kurallarının çıkış noktası 1944 yılındaki bir faciaya dayanmaktadır. 1944
yılında Amerikan donanmasının Pasifik Okyanusunda tropik bir fırtınaya
yakalanması sonucunda kısa süre içinde 3 adet destroyer batmış ve dördüncüsü de
bacasının rüzgar basıncı altında kırılması sayesinde kurtulmuştur. Bu facia,
Amerikan donanması için stabilite kurallarının geliştirilmesinde etkileyici rol
oynamıştır. Ilk kurallar 1962'de Sarchin ve Goldberg tarafından yayınlanmıştır. Bu
kurallar diğer ülkelerin donanmaları tarafından adapte edilmiştir.
Askeri gemilerin stabilitesi amaçları gereği büyük önem taşımaktadır. Çünkü
geminin hem gerekli stabilite kurallarını sağlaması, hem de görevini yerine getirecek
kabiliyette olması gereklidir. Görevini yerine getirirken herhangi bir zafiyete
uğramaması gerekmektedir.
ANEP 77 hasarsız stabilite kodu ile amaçlanan, NATO'ya üye ülkeler ve bu kodu
kullanmak isteyen diğer ülkelerin inşa edecekleri askeri gemiler için ortak bir
standart oluşturmaktır.
Bu çalışmada da ANEP 77 askeri gemi kodu ile dünya genelinde kullanılan Alman
askeri gemi kodu olan BV 1030-1, İngiliz askeri gemi kodu olan NES 109 ve ticari
gemilere uygulanan uluslararası stabilite kodu olan 2008 IS kod'un hasarsız stabilite
kriterleri ve hangi yatırıcı moment kollarının nasıl hesaplanacağı ile ilgili bilgiler
verilmektedir. Böylelikle genelde uygulanması amaçlanan bir kodun mevcut kodlarla
karşılaştırması elde edilecektir. Sonuçlar bölümünde yukarıda belirtilen 4 adet kodun
bir ticari kuru yük gemisi ve 2 adet savaş gemisi üzerinde uygulanması ve
karşılaştırmalı sonuçları verilmektedir.

Abstract:
Stability is one of the most important safety features of ships, and in particular of
small ships which tend to suffer from insufficient stability which could lead to the
capsizing of the vessel and loss of lives. It is, therefore, essential to design a ship
with adequate stability and to maintain it in all conditions of loading during its
operation.
Development of the concept of metacentric height apparently originated with
Bouguer in 1746. Derivation and calculation procedures for the righting lever curves
were published by Atwood in 1796. Development of quasi-dynamic stability and the
concept of the energy balance method was advanced by Moseley in 1850.
Several proposals for the use of a GM based stability criteria were offered in the late
1800s, and proposals for criteria based on righting energy have existed since early
1900s.
The major historical work on the stability of ships was carried out by Rahola in 1939.
Rahola's work involved a detailed analysis of Baltic ship capsizings and included a
proposal for a GZ based criteria.
Wind heeled GM requirements have been applied in the US since the 1940s and
became a US requirement for cargo ships in 1952.
Based on recommendations from the 1960 International Conference on the Safety of
Life at Sea (SOLAS 60), the IMCO sub-committee on Subdivision and Stability was
formed in 1962. The first international stability criterion, Resolution A.167, largely
based on Rahola's GZ criteria, was adopted by the IMO in 1968 for ships under
100m.
The IMO assembly adopted Resolution A.562 in 1985. This resolution was an energy
balance criterion, and also included a wind heeling recommendation, and was to be
used as a supplement to A.167.
The IMO assembly adopted Resolution A.749(18) on 4 November 1993. (Code on
Intact Stability for all Types of Ships Covered by IMO Instruments).
Intact Stability Code (IS Code) have been used since 1 July 2010, instead of
A.749(18). This historical development is related to the merchant ships intact
stability criteria.
For merchant ships today, stability is regulated by the criteria and rules issued by the
International Maritime Organization (IMO). Although IMO only recommends the
fulfilment of some of these criteria, usually all newbuildings have to meet the
requirements as they are made mandatory by the respective flag state authorities.
Intact stability for naval ships is more important and crucial than the merchant ships.
Naval ships are different as compared to merchant ships by the construction and
purpose of use. Generally, naval ships are more damage resilient and armed with
weapon systems.
For the intact stability of naval ships, there are no internationally agreed and applied
rules. Each country uses their own naval ship rules which reflect their needs. The
most known naval rules are BV 1030-1 rules of Germany and NES 109 rules of the
United Kingdom. The primary starting point of the most of naval ship rules was the
typhoon of December 1944. The US Pasific fleet was caught in a major tropical
typhoon and many ships were lost. After this disaster, first rules were published by
Sarchin and Goldberg in 1962.
The International Naval Safety Association (INSA) was established in April 2008 in
order to develop and maintain the Naval Ship Code. INSA is a group consisting of
navies and classification societies. The UK MoD is one of the founding members of
INSA.
The Naval Ship Code (NSC) is a goal based standard that determines a minimum
level of safety for naval vessels. It is the formal document published by NATO (as
ANEP77) which includes the Code and supporting Guide. The overall aim of the
Naval Ship Code is to provide an internationally accepted standard for naval surface
ship safety based on and benchmarked against IMO conventions and resolutions that
embraces the majority of ships operated by the Navies.
The basic principle of a goal based approach is that the goals should represent the top
tiers of the standards, against which ship is verified both at the design and
construction stages, and during ship operations.
A "goal-based" standard, rather than relying on the existing rules, considers what the
ultimate safety objective of the designer might be, and will consider a range of
alternative design approaches that will reach this desired goal. Thus, whereas in the
past the rules would have been specific over every detail, now, the over-arching
objectives will be specified, giving the designer choice, and the freedom to innovate.
A general information about "The Naval Ship Code (ANEP 77)" is given in the
second chapter.
In the third chapter, general information about "BV 1030-1" is presented. BV 1030-1
is the stability criteria which is applied to German naval ships. The rules are
applicable to the monohull naval surface ships.
Kurt Wendel first drafted the stability regulations for the German Federal Navy in
1961. Wendel issued a new edition of the regulations known as BV 1033 in 1964. An
early detailed explanation of the regulations and their background is due to Arndt
(1965). His paper was soon translated into English by the British Ship Research
Association and appeared as BSRA Translation No. 5052. An updated version of the
regulations was published in 1969 and since then they are known as BV 1033. As
pointed out by Brandl (1981), the German regulations were adopted by the Dutch
Royal Navy and they also served in the design of some ships built in Germany for
several foreign navies. The rules were finally revised and published in 2001 as BV
1030-1.
In the third chapter, the information about the operational areas, loading conditions,
obtaining the righting and heeling arms and intact stability requirements are given.
In the fourth chapter, general information about "NES 109" is given. NES 109 is the
stability criteria applied to the UK naval ships.
The stability standards of the Royal Navy evolved from the criteria published by
Sarchin and Goldberg in 1962. The first British publication appeared in 1980 as NES
109. The currently valid version is Issue 4 (MoD, 1999a). The British standard was
issued by the Ministry of Defence (MoD) and is applicable to vessels with a military
role, to vessels designed to the MoD standards but without a military role, and to
auxiliary vessels. The vessels with a military role are those exposed to enemy action
or to similar dangers during peacetime exercises. The standard NES 109 has two
parts; the first is dealing with conventional ships, the second is with unconventional
vessels. The second category includes; monohull high speed vessels, multihull
vessels and dynamically supported vessels.
In chapter four of this study, the provisions for conventional vessels are presented.
These provisions include the operational areas, moment arms, stability criteria and
loading conditions.
In the fifth chapter, general information about "2008 IS Code" is given. 2008 IS
Code is the most recent stability criteria of IMO for the merchant ships.
The purpose of the Code is to present mandatory and recommended stability criteria
in a single document and other measures for ensuring the safe operation of ships, to
minimize the risk to such ships, to the personnel on board and to the environment.
The Code has two parts. The mandatory requirements are given in part A and
recommended provisions are given in part B. Although part B is recommended in
nature, classification societies and flag states apply this part as mandatory.
This code is applicable for cargo ships, cargo ships carrying timber deck cargoes,
passenger ships, fishing vessels, special purpose ships, offshore supply vessels,
mobile offshore drilling units, pontoons and cargo ships carrying containers on deck
and container ships of 24 m in length and above.
In chapter five, the calculation details and assumptions related to loading conditions
and stability criteria are presented.
In chapter six, the application of ANEP 77, BV 1030-1, NES 109 and 2008 IS Code
to an ocean going general cargo ship, a navy surface combatant and an auxillary type
naval vessel is given. The full load departure and full load arrival loading conditions
of each vessel type are taken into account in the analyses. For each loading
condition, hydrostatic particulars, righting arm (GZ) curve, wind heeling moment
arms according to the codes, heeling arms due to turning and passenger crowding
and evaluation of stability criteria are presented in this chapter.
In chapter seven, results and overall assessments are presented. According to the
results, it couldn't be said that one code is the best and applicable to all ships. Each
code has its own positive or down sides. For example; if the wind pressure is taken
equal in each code, 2008 IS Code has the most stringent weather criterion. However,
the assumed wind speed according to the operational areas is different. In this case,
ANEP 77 is the most stringent, because the wind speed is 100 knots for the unlimited
ocean going operational area. In another case, if NES 109 and 2008 IS Code are
compared, NES 109 has the most stringent criteria in terms of the area under GZ
curve criteria and probably application of NES 109 to merchant ships is impractible.
Consequently, ANEP 77 and NES 109 resemble each other in general. Area under
GZ curve criteria are eliminated in ANEP 77. Each heeling arm is compared with the
respective righting arm. In this case, if the operating conditions are defined well,
ANEP 77 offers a large working area to designers.