INTERNATIONAL

420
CLASS RULES

2011
Authority*: International Sailing Federation
Ariadne House, Tow n Quay, Southam pton SO14 2AQ* The International Sailing Federation (ISAF) is not a National Authority ( NA)2011 International 420 Class Rules 23rd September. 20101

INDEXPART I – ADMINISTRATION

C.8

Hull Appendages................................

C.9

Rig......................................................

C.10

Sails....................................................

Section A – General
Section D – Hull

A.1

General Information…………………...

A.2

Language............................................

A.3

Abbreviations......................................

A.4

Authorities and Responsibilities………

A.5

Administration of the Class.................

A.6

ISAF Rules..........................................

A.7

Amendments to Class Rules…............

A.8

Class Rules Variations..……...............

A.9

Interpretations of Class Rules.............

A.10

ICA fee ICA Plaque & Sail button.......

E.1

Measurement........................................

A.11

Certification & Measurement

E.2

Centreboard..........................................

certificate……………………….............

E.3

Rudder…………....................................

A.12

Validity of measurement Certificates...

A.13

Re- Certification...................................

Section B – Boat Eligibility
B.1

Certificate…………………………….......

B.2

Certification mar ks. ...............................

B.3

Class membership………………...........

B.4

ICA Plaque ……….………………..........

B.5

Builder’s Plaque……………….…..........

PART II – REQUIREMENTS AND
LIMITATIONS
Section C – Conditions for Racing
C.1

General................................................

C.2

Crew ....................................................

C.3

Personal Equipment.............................

C.4

Advertising......................................

C.5

Portable Equipment.............................

C.6

Boat......................................................

C.7

Hull.......................................................

D.1 Certification…...........................................
D.2 Manufacturers…………............................
D.3 Building & Materials for Building…............
D.4 Assembled Hull.........................................
D.5 Hull Weight……….....................................
D.6 Corrector Weights.....................................
Section E – Centreboard, rudder & tiller

Section F – Rig
F.1

Measurement........................................

F.2

Mast......................................................

F.3

Boom.....................................................

F.4

Spinnaker Pole......................................

F.5

Rigging & fittings………….....................

Section G – Sails
G.1

Measurement........................................

G.2

Certification…........................................

G.3

Mainsail.................................................

G.4

Headsail................................................

G.5

Spinnaker............................................

2011 International 420 Class Rules 23rd September. 20102

PART I – ADMINISTRATION___________________________________________________________________

Section A – GENERAL
A.1

GENERAL INFORMATION

A.1.1

The International 420 Class Association class rules are closed class rules.

A.1.2

The 420 is a one-design class. The intention of these rules is to ensure that the boats
are as alike as possible in all respects affecting performance, in order that crews maycompete against each other on level ter ms.

A.1.3

These rules are complementary to the Lines plan (plan de formes), the building
specifications (Draw ing N° 5), the International 420 Class Association (ICA) rudder
blade draw ing and the 420 International Measurement Form (IMF). The current issue ofthese official documents is listed at the end of this document. These items, how evercomplete, cannot anticipate every situation that may arise. If a point is not clearly
covered, a ruling shall be obtained from the ISAF through the ICA technical Committee.

A.2

LANGUAGE

A.2.1

The official language of the Class is English and in the event of dispute overinterpretation, the English text shall prevail.

A.2.2

The w ord “shall” is mandatory and the w ord “may” is permissive.

A.2.3
A.2.4

The ter m "per manent" shall mean unable to be removed w ith simple tools, or fixed w ith
glue or rivets. For limit mar ks, it shall mean unable to be removed and repositioned
without destroying them.
All units are metric and all dimensions unless otherw ise stated are in millimetres.

A.3

ABBREVIATIONS

A.3.1

ISAF
MNA
ICA
IMF
NCA
ERS
RRS

International Sailing Federation
ISAF Member National authority
International 420 Class Association
420 International Measurement For m
National 420 Class Association
Equipment Rules of Sailing
Racing Rules of Sailing

A.4

AUT HORITIES AND RESPONSIBILITIES

A.4.1

The International authority of the class is the ISAF, w hich shall co-operate w ith the ICA
in all matters concerning these class rules.

A.4.2

Neither the ISAF, an MNA, the ICA, an NCA, a certification authority, or an official
measurer are under any legal responsibility in respect of these class rules and theaccuracy of measurement, nor can any claims arising from these be entertained.
Notw ithstanding anything contained herein, the certification authority has theauthority to w ithdraw a certificate and shall do so on the request of the ISAF.

A.4.3

2011 International 420 Class Rules 23rd September. 2010

3

A.5

ADMINIST RATION OF THE CLASSThe Class is administered by the ICA, in conjunction w ith the ISAF. The ICA may
delegate parts or all of its functions, as stated in these class rules, to an MNA or an
NCA.

A.6

ISAF RUL ES
These class rules shall be read in conjunction w ith the current version of the ERS.
When a ter m is used in its defined sense, it is printed in bold type if defined in the ERS
and in italic type if defined in the RRS.

A.7

AMENDM ENTS TO CLASS RUL ES

A.7.1

Amendments to these Class Rules shall be proposed by the ICA and are subject tothe approval of the ISAF in accordance w ith the ISAF regulations.

A.8

CLASS RUL ES VARIATIONS

A.8.1

At World or Continental Championships the notice of race and sailing instructions maychange the class rules only w ith the agreement of the ICA and the ISA F.

A.9

INT ERPRETATION OF CLASS RUL ES

A.9.1

GENERAL
Except as provided by A.9.2, interpretation of these class rules shall be made by ISAF
in conjunction w ith the ICA. Request for an interpretation shall be made in accordancewith the ISAF regulations.

A.9.2

AT AN EV ENT
Any interpretation of class rules required at an event may be made by an international
jury, constituted in accordance with the RRS appendix N. In this case, the jury shallconsult the event chief measurer. Such interpretations shall be valid only during theevent, and the organizing author ity shall, as soon as practical after the event, informthe ISAF and the ICA of such an interpretation.

A.10

ICA FEE, ICA PLAQUE AND SAIL BUTTONS

A.10.1The ICA fee is to be set annually by the ICA and may increase in line w ith the annual
recommendation from ISAF.

A.10.2The treasurer of the ICA, after having received the class fee, shall send to the licensed
builder the ICA Plaque, w ith the sail number allocated to the boat.

A.10.3

Licensed builders shall pay for a minimum of ten plaques each year to the treasurer of
the ICA.

A.10.4.

The Sail number for each boat is allocated by the ICA and specified on the ICA Plaque.

A.10.5Competitors may use the sail number of any hull still ow ned by them, on any boat
chartered or ow ned by them.

A.10.6

Each sail first certified after 1st March 2005 shall have permanently fixed an officiallynumbered ICA sail button. No sail shall be accepted for certification control without asail button. Sail buttons shall not be transferred from a sail to another.

2011 International 420 Class Rules 23rd September. 2010

4

A.11

CERTIFICATION AND MEASUREMENT CERTIFICAT E

A.11.1

For a hull not previously certified, certification control for all items to be measured
and to be in conformity w ith the Official documents shall be carried out by an official
measurer, and the details entered into the IMF w hich, when completed, shall be
supplied to the ow ner by the builder.

A.11.2

Certification control shall be carried out only by official measurers appointed bothby their MNA and the ICA. An official measurer shall not perform certification control
on any part ow ned, designed or build by him, or in w hich he is an interested party, or
has a vested interest, except where permitted by these class rules.

A.11.3The IMF is necessary to obtain the measurement certificate. The measurement
certificate is obtained as follow s:
The ow ner shall send the IMF together w ith any registration fee to the certification
authority in the country where the boat is to be registered. Upon receipt of asatisfactorily completed IMF and the fee, the certification authority issues themeasurement certificate to the ow ner. The certification authority shall retain a copyof the IMF.

A.12
A.12.1VALIDITY OF THE MEASUREM ENT CERTIFICAT E
A certificate is still valid after an alteration of the corrector weights only if the hull is
re-w eighed by an official measurer. When the hull is re-weighed, the measurer shallenter the details on the IMF and the Measurement certificate shall be endorsed by thecertification authority.

A.12.2

A Measurement certificate becomes invalid upon:a) Change of ow nership,b) Alterations other than permitted routine maintenance such as small repairs,
painting, sanding and polishing to items required by the IMF to be measured,c) Withdraw al by the certification authority,d) The issue of a new certificate.

A.13

RE-CERTIFICATION

A.13.1

Upon change of ow nership, the new ow ner shall apply to the certification authority
where the boat w ill be registered for a new measurement certificate. The application
shall include the old measurement certificate, the IMF, and any registration fee that
may be required. A new measurement certificate shall then be issued to the newow ner.

A.13.2

Upon alteration or repair to an item required by the IMF to be measured, the relevant
item shall be re-measured by an official measurer and the details entered on the IMF.
The ow ner shall apply for a new measurement certificate (see A.13.1 for theprocedure).

A.13.3

When the certificate has become invalid under A.12.2 (c), the certification authority
may issue a new certificate at its discretion.

2011 International 420 Class Rules 23rd September. 20105

Section B – BOAT ELIGIBILITY
For a boat to be eligible to race, the rules in this section shall be complied w ith.
B.1

CERTIFICAT E
No crew shall take part in class races unless the boat has a valid measurement
certificate, in English or w ith English subtitles, including corrector weight details.

B.2

CERTIFICATION MARKS
Each sail shall carry a valid certification m ark according to G.2.1.

B.3

CLASS MEMBERSHIPThe crew shall be current members of a NCA.

B.4

INT ERNATIONAL 420 CLASS ASSOCIATION PLAQUE
The ICA Plaque shall be affixed to the hull, as specified in D.1.5

B.5

INT ERNATIONAL 420 BUIL DER’S PLAQUE
The builder’s Plaque shall be affixed to the hull, as specif ied in D.1.5

2011 International 420 Class Rules 23rd September. 2010

6

PART II – REQUIREMENTS AND LIMITATIONS________________________________________________________________

The crew and the boat shall comply with the rules in Part II when racing. M easurement to checkconformity with rules of Section C is not part of equipment certification control.

Section C – CONDITIONS FOR RACING
C.1

GENERAL

C.1.1

MEASUREM ENT
Unless otherw ise stated, measurement shall be carried out in accordance w ith thecurrent version of the ERS.

C.1.2

RUL ES

C.1.2.1

If the wind speed is consistently 13 knots or above, measured at deck level, therace committee may permit pumping, rocking and ooching as stated in RRS
P5. If the Race Committee displays flag “O” before or with the warning signal,these actions are permitted from the preparatory signal.

C.1.2.2

RRS 49.1 is modified as per class rule C3.2

C.2

CREW

C.2.1

LIMITATIONS

C.2.1.1

The crew shall consist of two persons, each in contact w ith the boat.

C.2.1.2

No crew member shall be substituted during an event w ithout the approval of the Race
Committee.

C.2.2

RESPONSIBILITY OF T HE CREW
It is the crew ’s responsibility to ensure that the boat and personal equipment comply
with the class rules when racing.

C.3

PERSONAL EQUIPM ENT

C.3.1

MANDATORY
When racing, each crew member shall w ear personal buoyancy to the minimum
standard ISO 12402-5 (Level 50) or equivalent. Inflatable buoyancy vests are notpermitted.
RRS 43.1 shall apply, w ith the amendment that each crew member’s personalequipment shall w eigh 9 kg maximum, including footw ear and clothing w orn below theknees but excluding the trapeze harness.

C.3.2

OPTIONAL
As an alteration to RRS 49.1, a trapeze may be used, but only one member of thecrew shall use a trapeze harness. The trapeze harness shall not be filled w ith ballast,shall float, and shall have a maximum w eight of 4 kg (Weight shall be deter mined as
required by RRS Appendix H).

2011 International 420 Class Rules 23rd September. 2010

7

C.4

ADV ERTISING

C.4.1

CATEGORY
Advertising including competitor advertising is permitted in accordance w ith ISAF
Regulation 20 - Advertising code except that the areas are amended by C.4.2.

C.4.2

LIMITATIONSEvent and Competitor Advertising on the boat ispermitted only in the follow ing positions (seediagram 1) Manufacturer marks are as per theadvertising code:(a) Event advertising:
Hull: the outside hull shell betw een 600 mm
and 1650 mm from the foremost point (fittings
excluded)
Boom : the foremost 480mm of the boom spar(b) Competitor advertising:
Hull: the outside hull shell aft of 1650 mm fromthe foremost point (fittings excluded)
Mainsail: below sail numbers
Spinnaker: below sail numbers.
Mast : Unlimited
Boom : aft of 480mm from the spar’s foremost
point

C.4.3

IDENTIFICATION DURING RACESThe outside hull shell betw een the foremost point and 600 mm from the foremost point
shall be intended only for the boat identification if specified in the Sailing Instructions,or shall be w ithout advertising if nothing is specified in the Sailing instructions (seediagram 1)

C.5

PORTABL E EQUIPMENT

C.5.1

FOR USEa) OPTIONAL
1)

One hand bailer or bucket and/or sponge

2)

C.5.2

One compass fixed to a mounting bracket. The compass shall not recess intoeither side tank or deck. The mounting bracket may be attached on the m ast
or may be used to close the mast gate. If electronic, only a compass w ith
heading, heading memory and timing functions is permitted.Electronic ormechanical timing devices, w hich shall be removable.
NOT FOR USEa) OPTIONAL
1) One paddle
2) Spare parts such as blocks, shackles, ropes etc.
b) MANDATORY

2011 International 420 Class Rules 23rd September. 20108

1)

The boat shall be fitted w ith a floating tow ing rope of a minimum length of 8
meters and minimum diameter of 8 mm, secured to the m ast, and w hich can be
grasped at the stem (even if the boat is capsized) from a rescue boat.

C.6.

BOAT

C.6.1

WEIGHT
The boat fully rigged for sailing and in dry condition, but excluding sails, tow ing rope,
personal and portable equipment shall have a minimum w eight of 100 kg. A compass
with associated bracket, if present, shall be included in the boat w eight. Corrector
weights, including any required by D.6, shall have a maximum w eight of 2 kg.

C.6.2

FLOTATION

C.6.2.1

The boat shall have tw o side buoyancy tanks and one in the front. At initialcertification control, the measurer shall check the w ater-tightness of the buoyancy
tanks, inspection ports and drain plugs. If the buoyancy is unsatisfactory, the measurer
shall not sign the IMF until satisfactory remedial measures have been taken. Thereafter, it is the responsibility of the competitor/ow ner to ensure the water-tightness ofthese tanks.

C.6.2.2

Inspection hole covers and drainage plugs shall be kept in place w hen racing.

C.7

HULL

C.7.1

FITTINGS
Rigging and fittings listed hereunder shall be fitted and used only as specified. Except
where otherw is e specif ied, the direction of the control lines, sheets, and ropes shall not
be modified by means of shackles, rings, loops thimbles or holes in the boat. Fittings
listed hereunder shall comply w ith the current class rules. All fittings, fastenings andlocal reinforcement for fittings shall be only for their normal purpose and shall not be
used to increase the w eight of the boat.

C.8

HULL APPENDAGES

C.8.1

LIMITATIONS
Only one centreboard and one rudder blade shall be used during an event except incase of loss or damage beyond repair. Such replacement may be made only w ith theapproval of the race committee.

C.8.2

CENT REBOARD(a) USEThe centreboard shall be fitted by means of an axis pin through a hole in thecentreboard case, which may include a bushing. When fully raised, no part of thecentreboard shall project below the hull surface.

C.8.3

RUDDER(a) USE2011 International 420 Class Rules 23rd September. 20109

No part of the rudder blade, w hen fully low ered, shall extend more than 540 mm
below the HDP. The leading edge of the rudder blade shall not be forw ard of avertical line through the HDP (see measurement diagram 2).

BASE LINE

540 MAXNO PART OF THE RUDDE R
SHALL BE FORWARD
A VERTICAL LINE THROUGH
THE HULL DA TUM POINT

Diagram 2
C.9

RIG

C.9.1

LIMITATIONS
Only one m ast, boom and spinnaker pole shall be used during an event, except incase of loss of damage beyond repair. Such replacement may only be made w ith theapproval of the Race Committee.

C.9.2

MAST
(a) USE
1) Chocks may be used to control the fore and aft bend of the mast spar at the mast
partner.
2) The mast heel position shall not be adjusted on the mast step w hen racing.
3) Adjustable spreaders –if used- shall not be able to be remotely controlled, and shallnot be adjusted w hen racing.
4) The effective length of the shrouds shall not be adjusted w hen racing.
5) The forestay under tension shall be entirely in metal and shall prevent the mast from
disengaging from the mast partners. To meet this requirement the w idest section of themast shall be w ithin the mast partners w hen the mast rakes under its own weight andthe forestay comes under tension, as in Diagram 3. The forestay shall be connected tothe stemhead fitting w ith either: a shackle, a rigging plate w ith holes and pins, a steel
wire rope strop of minimum diameter of 2mm or any combination of the above. Elastic
rope tied on the forestay and the stemhead is per mitted.

DIAGRAM 3

2011 International 420 Class Rules 23rd September. 2010

10

C.10

SAILS

C.10.1

MAINTENANCE

C.10.1.1

Routine maintenance such as sew ing, mending and patching is permitted w ithout recertification. Altered sails shall be re-certified and the official measurer shall placea new certification m ark on the sail w ith the new date of certification control.

C.10.2

LIMITATIONS

C.10.2.1

Not more than one mainsail, one jib and one spinnaker shall be carried aboard w hen
racing.

C.10.2.2

Not more than one mainsail, one jib and one spinnaker shall be used during an event,except w hen a sail has been lost or damaged beyond repair, or w hen otherw is e
specified in the sailing instructions. Such replacement may be made only w ith theapproval of the race committee.

C.10.3

MAINSAIL

C.10.3.1

IDENTIFICATION
Identification shall comply w ith the RRS except w here mentioned hereunder:
As an alteration to RRS Appendix G 1.3 (a), the follow ing items shall be positioned oneach side of the sail as follows:(a) National letters above and below and adjacent to the second batten from thetop, port and starboard not overlapping each other, those on starboard side
being upper most.
(b) Sail numbers above and below and adjacent to the third batten from the top,
port and starboard not overlapping each other, those on starboard side being
uppermost.
(c) Mainsails used in w omen’s only events shall carry a red rhombus (length of
diagonals 250mm minimum) above the top batten pocket on both sides. The
position should be approximately in the centre of the triangle formed by the top
batten and the mainsail head. The rhombus may be retained for racing in otherevents.
Numbers and letters shall be in red, of a minimum w idth of 200 mm (except number 1
and letter I), of a minimum thickness of 45 mm and of a minimum height of 300 mm.
Other dimensions and indications regarding letters and numbers are specified in RRS.
All numbers, letters and the emblem shall be of paint or other, securely attacheddurable material.

C.10.3.2

USE

C.10.3.2.1 The sail shall be hoisted on a halyard. The arrangement shall per mit hoisting andlow ering of the sail while afloat w ith the boat upright.
C.10.3.2.2 The sail shall be set so that the highest visible point of it, projected at 90° to the mastspar, shall not be higher than the upper point, and the aft-most visible part of theleech, projected at 90° to the boom spar, is forward of the outer point on the boom.
C.10.3.2.3 Luff and foot bolt ropes shall be in the respective spar grooves or tracks.
C.10.4JIB

C.10.4.1

USE
The sail shall be hoisted on a halyard. The arrangement shall per mit hoisting andlow ering of the sail while afloat w ith the boat upright.

C.10.4.2

Only one steel luff w ire of minimum diameter of 2mm shall be fitted inside the jib luff
sleeve w hen racing.

2011 International 420 Class Rules 23rd September. 201011

C.10.5

SPINNAKER

C.10.5.1

Identification
Identification shall comply w ith RRS, except w here mentioned hereunder:
As an alteration to RRS Appendix G 1.3 (d), national letters are optional.
If positioned, national letters may be in line w ith the sail numbers. The colour of lettersand numbers is optional, but they shall be all of the same colour, fully painted, andshall contrast w ith the colour of the panel to w hich they are positioned, of a minimum
width of 200 mm (except number 1 and letter I), of a minimum thickness of 45 mm andof a minimum height of 300 mm. Other dimensions and indications regarding lettersand numbers are specified in RRS.
All numbers and letters shall be of paint or other, securely attached durable mater ial.
Numbers and letters, if on both sides, shall not overlap and shall be placed at different
heights w ith a minimum space of 60 mm.

C.10.5.2

USE
The sail shall be hoisted on a halyard. The arrangement shall per mit hoisting andlow ering of the sail while afloat w ith the boat upright.

2011 International 420 Class Rules 23rd September. 201012

Section D – HULL AND DECK
D.1

CERTIFICATION

D.1.1

Only an official measurer shall measure the hull and sign the declaration on the IMF
that it complies w ith the class rules, lines plan and building specification (Draw ing 5).
Measurements to ensure the conformity of the hull are specified on the IMF but theintention is that beyond these measurements, the hull shall completely conform to the
Official Documents.
To be certified in conformity w ith the class rules, Lines Plan and Building specification(Draw ing N° 5) the hull shall comply w ith the official documents in force at the time ofinitial certification control.

D.1.2

D.1.3

Measurement shall be carried out in accordance w ith the current version of the ERS.

D.1.4

Templates used for certification control of hull shall be supplied by the ISAF.
Tolerances are only given to allow minor building errors and shall not be deliberately
used to alter the design. The boat, before leaving the builder’s premises shall bemeasured by an official measurer. The measurer shall report on the IMF w hat heconsiders being a departure from the intended nature and design of the boat, and themeasurement certificate may be refused.

D.1.5

No boat shall leave the builders’ premises w ithout the ICA plaque and the builder'splaque affixed. The builder's Plaque shall mention:- The trade mark of the boat
- The name and the address of the builder- The year of building.
The ICA plaque shall mention:- The ISAF logo
- The ICA logo
- The sail number allocated to the boat
The ICA plaque shall be affixed on the starboard side tank, close to the transom andthe builder's plaque on the inside transom (see also rules B.4 and B.5)

D.2

BUIL DERS

D.2.1

International 420 hulls shall be moulded and assembled only by licensed builders.
Application for a licence shall be made to the ISAF w hich shall consult w ith the ICA andthe MNA of the country where the builder has its yard before granting a license. Hulls
shall be supplied only as per manently assembled boat units. Rigs, sails, hull
appendages and fittings may be produced by any manufacturer.

D.2.2

Licensed builders have the sole responsibility that their production moulds, plugs andassembled boats comply w ith the relevant class rules and official documents.

D.2.3

If a builder does not comply w ith the requirements quoted in the class rules and the
Official documents, the ISAF may revoke the license on the recommendation of the
ICA.

D.2.4

If a builder is found to have supplied a boat that does not comply w ith the rules inapplication, he shall be liable to rectify the error, and may have his license as a builder
withdraw n.

D.3

BUIL DING AND MATERIALS FOR BUILDING

D.3.1

The hull shall be build in conformity w ith the building specifications (Draw ing N° 5)

D.3.2

Mater ials used for building shall be those specified on the Building specification(Draw ing N°5).

2011 International 420 Class Rules 23rd September. 201013

D.3.3No less than 0.05 m3 of positive buoyancy shall be securely attached in each side tankto give approximately equal buoyancy laterally and longitudinally. The buoyancy shallbe of closed cell rigid foam, or alternatively of air containers of not less than two litres
each. It shall not be used as reinforcement.

D.3.4

Non-slip material, tape and low-friction material not exceeding 4mm in thickness may
be added to the hull as long as it does not change the stiffness of the hull.

D.4

ASSEMBL ED HULL

D.4.1

DIM ENSIONS AND MEASUREM ENT

D.4.1.1

The hull datum point ( HDP) is the intersection on the hull centre plane of the transom
external surface w ith the underside of the hull surface, both extended as necessary.
The aft measuring point (AMP) is the projection of the HDP on the baseline.

D.4.1.2

For fundamental measurement of boats built by current fully licensed builders after
the 1st July 2007 the base line shall be set at 200 mm below the HDP and 92 mm
below the keel at 3780 mm from the HDP. For new builders the effective date is 1st
March 2006. Current licensed builders may also use this system before July 1st 2007.
All measurements carried out from the HDP shall be made parallel to the baseline anddepth measurements perpendicular to the base line. Measurement sections shall be
perpendicular to the base line.

D.4.1.3

The hull length shall be minimum 4180 mm and maximum 4220 mm.

D.4.1.4

Measurement sections 1 to 10 shall be at the follow ing positions from the HDP:
Section 1: at 380 mm from HDP.
Section 2: at 780 mm from HDP.
Section 3: at 1180 mm from HDP.
Section 4: at 1580 mm from HDP.
Section 5: at 1980 mm from HDP.
Section 6: at 2380 mm from HDP.
Section 7: at 2780 mm from HDP.
Section 8: at 3180 mm from HDP.
Section 9: at 3580 mm from HDP.
Section 10: at 3980 mm from HDP.
Vertical distance from baseline to underside of hull shell;at section 1
at section 2
at section 3
at section 4
at section 5
at section 6
at section 7
at section 8
at section 9
at section 10

D.4.1.5

Minimum
154 mm
116 mm
84 mm
55 mm
34 mm
20 mm
15 mm
24 mm
56 mm
129 mmMaximum
170 mm
132 mm
100 mm
71 mm
50 mm
36 mm
31 mm
40 mm
72 mm
145 mmCertification control of boats shall be performed at stations 2, 5, 8, 9 & 10. If themeasurer is in doubt regarding the conformity of the hull to the lines plan, the hull may
be checked at all measurement sections. Prototype measurement for mould approvalshall be performed at all 10 stations.

2011 International 420 Class Rules 23rd September. 2010

14

Hull
Datum
Point

116 min
132 max

24 min40 max34 min50 max

200

92

780

Aft
Measurement
Point

1980

BASELINE

3180

Forward
Measurement
Point

3580
3780
3980

2

5

8

9

10

POSITION OF THE MEASUREMENT SECTIONS

Diagram 4
D.4.1.6

129 min
145 max

56 min72 maxSection templates shall be applied as show n on diagrams 5 and 6. The top of the deckat the sheerline as defined in the building specification shall be not more than 10 mmabove or below the sheerline marks on the templates. The gunw ale shall touch thetemplates or clear by a maximum of 50 mm. Below line 1, the templates shall touch thehull or clear by not more than 16 mm, and the difference between the greatest andleast clearance shall not exceed 12 mm.
Measurement at sections
5&6

Th e Top of the d eckat the sheerlin e shallbe wit hin the limits specified
on th e templates

Prolon gatio nof hull

Measurem ent Point

LINE 1( 400 m m f rom the B ase Line)0 mi n
1 6 m ax

belo w t he li ne 1

Te mplate s sh all
touch the h ull
at cen tre exce pt
templa te 5

No measur ement of hul l shel l

Diagram 5
Diagram 6

D.4.1.7

The stem template shall be applied as show n on measurement diagram 7. The
template shall touch the stem or clear by not more than 15 mm.

T he T op of the deckat the sheerline shallbe within the limits specified
on the templates
20 min40 max
523 min
543 max
0 min
15 max(withou t deck o verlap)

HDP

200
BAS ELINE

Vertical line
Aft Measurement Point( Pr ojection of HDP)

92
BASEL IN E

Forward
Measurement
Point

Vertic al line

Diagram 83780 from Aft
Measurement Point

Diagram
7
2011
International
420 Class Rules 23rd September. 201015

D.4.1.8

The transom template shall be applied as show n on measurement diagram 8. The
distance betw een the transom and the template shall be minimum 20 mm andmaximum 40 mm except at the deck overlap.
The transom radius shall be checked in a horizontal plan located 400 mm above thebaseline. On each side, the curvature measured at 520 mm from the centreline shall be
26 mm minimum and 42 mm maximum (see measurement diagrams 9 and 10).

D.4.1.9

min 26, max 42,
measured on line 1

LINE 1

400 mmBASELINE

520 mmmin 26, max 42,
measured on line 1
CENTRELINE

Diagram 10

Diagram 9

D.4.1.10

The centreboard case shall be in position as show n on measurement diagram 11 andthe Draw ing No. 5. The forw ard upper part of the centreboard case shall be 330 mm
minimum above the underside of the hull, and the aft upper part shall be 295 mm
minimum above the underside of the hull. Overall, the centreboard capping w idthshall be a maximum of 170 mm.

2 95 MIN

33 0 MINBASELINE
14 15 MIN
25 10 MAX

Diagram 11
D.4.1.11

The boat shall conform to all the dimensions specified on the draw ing n° 5.

D.4.1.12

The convex curve of the foredeck shall be measured by placing a 300 mm straight edge
on any part of the deck forw ard of the breakwater. In any plane the straight edge shallnot be flat against the surface of the deck.

D.4.2

ASSEMBL ED HULL FITTINGS

2011 International 420 Class Rules 23rd September. 201016

D.4.2.1(a)

The fittings listed hereunder shall be fitted and used only as specified. Cleatsmentioned in these rules, may incorporate a hook or an over-cleat fairlead. A
cleat w edge under each cleat is permitted. Except w hen specified, the direction of
the control lines, sheets and ropes shall not be modified by means of shackles,
rings, loops or holes in the boat. Control lines, ropes, sheets, halyards shall not
pass through the buoyancy tanks and/or the breakw ater.

(b)

No fittings, w ith the exception of: spinnaker sheet catcher(s), non-slip material on
the gunw ale, rudder fittings and transom drainage flaps shall project beyond theoutboard edges of the gunw ale or beyond the profile of the hull.

(c)

No fitting shall serve as an extension of the hull surface.

(d)Ballast shall not be carried.

(e)Mater ials for permitted fittings are optional except that Titanium is prohibited.

MANDATORY, WIT H POSITION OR DIMENSION SPECIFIED
The follow ing fittings shall be positioned in accordance w ith the drawing N°5 and shallbe used as specified(a)

One stem-head fitting for attachment of the forestay and the headsail. The
centre of the front hole of the stem-head fitting shall be at 4085 mm minimumand 4125 mm maximum from the HDP. Only one hole for the forestay and one
hole for the headsail are permitted. The forestay shall be attached to the front
hole and the headsail shall be attached to the aft hole.

(b)

Tw o shroud plates for the shrouds, one for each side of the boat. The centreof the hole of the shroud plates measured on the centreline shall be at 2550
mm minimum and 2570 mm maximum from the HDP.

(c)

One mainsheet track or bar of any profile, made only of metal or GRP. It shallbe straight and fixed to the centreboard case capping. The track or bar shallhave a maximum height of 40 mm and a maximum w idth of 40 mm. The
centreline of the track or bar shall be fixed to the side tanks at 1400 mm
minimum and 1500 mm maximum from the HDP.

(d)

One mast step fixed on the keelson. The length of the mast step shall be 150
mm maximum. The forw ard part of the mast step shall be at 2890 mm
minimum and 2910 mm maximum from the HDP. The bear ing surface of themast step shall be at 5 mm maximum from the top surface of the keelson.

(e)

Tw o headsail fairleads, the measurement point of w hich shall be at 2020 mm
minimum and 2120 mm maximum from the HDP and 625 mm minimum fromthe centreline. The fairleads shall be fixed directly to the buoyancy tanks (seediagram 12).

2011 International 420 Class Rules 23rd September. 201017

2020 MIN / 2120 MAX from HDP
Headsailfairlead625 MIN

2020 MIN / 2120 MAX from HDP

Headsail fairlead
Measurement Point

625 MIN

Diagram 12

D.4.2.2(f)

One drain hole in each buoyancy tank, located near the transom, w ith adiameter of 15 mm minimum and 25 mm maximum(g)A minimum of one inspection hole for each buoyancy tank w ith a minimum
diameter of 100 mm.

(h)

Tw o spinnaker bags located according to Draw ing 5.

(i)

At least one draining hole or port in the transom, w ith a maximum total area of
80 cm². Hinged covers or other devices for closing draining ports or drain
holes in the transom. These covers or devices shall not obstruct the rudder

MANDATORY, WIT H POSITION OR DIMENSION OPTIONAL(a)

Mainsail, headsail and spinnaker sheets(b)

Four single-sheave blocks for the mainsheet, one of w hich may be a ratchet
block. The mainsheet shall be attached to the block which is connected to thebridle. Tw o blocks shall be attached directly to the boom . The fourth block
shall be fixed to a mounting on the aft part of the centreboard case capping or
keelson. The maximum obtained purchase shall be 4:1.

(c)

A bridle made either ofi) Tw o strops, either of rope or w ire. Each strop shall be attached to a point on
the mainsheet bar/track or its end fittings, and to the mainsheet block, so
forming a tr iangle. Each strop may be adjustable by including one additional
permanently fixed eyelet and one snap hook/shackle fixed at the track/bar or
its end fittings, orii) Tw o strops of rope. The strop of each side shall pass through a sheave or
block attached to the end fittings of the mainsheet track/bar, and then end in acleat w ithout moving parts, fix ed on the mainsheet track/bar. One sheave andone cleat per side are the only fittings permitted.
Any other adjustment system is prohibited.

(d)

One kicking strap of rope and/or stainless steel w ire w ith a maximum of five
single-sheave blocks. One cleat w ithout moving parts and one guiding block
directly behind the cleat for the kicking strap system.

(e)

Tw o rudder fittings (pintles or gudgeons) for the rudder.

(f)

One sw ivelling cleat w ith moving parts fixed on the aft part or the centreboard
case capping or tw o cleats w ith moving parts on the side tanks for themainsheet.

(g)

Tw o cleats w ith moving parts, fixed on the side tanks, for the headsail sheets.

2011 International 420 Class Rules 23rd September. 201018

D.4.2.3(h)Tw o cleats w ithout moving parts, fixed on the side tanks, for the spinnaker
sheets.

(i)

One fairlead and one cleat w ith or w ithout moving parts for the spinnaker
halyard.

(j)

One cleat w ithout moving parts and one guiding block directly behind the cleat
for the spinnaker uphaul/dow nhaul system (adjusting the height of thespinnaker pole). An additional block, a rope and a device to attach the rope ispermitted betw een the m ast and the cleat mentioned above. Mast fittings forthe spinnaker pole uphaul/dow nhaul are mentioned in F 2.6.15.

(l)

A maximum of four fairleads (also mentioned in F.5.1.2) for the elastic cord of
the tw o trapeze w ir es(m)

Tw o spinnaker fairleads or blocks for the spinnaker sheets.

OPTIONAL
The follow ing fittings -if fitted- shall be used only as specified below :(a)One self-bailer(b)

Toe straps inside the cockpit area for the crew , adjustable by means of ropes
and knots or one cleat w ithout moving parts, and elastic cord to keep themlifted up.

(c)Spinnaker catcher fitting(s) which shall not project outside the gunw ale edges
or more than 150 mm beyond the bow .

(d)One hook on each side of the boat, on shrouds/shroud plates or fixed on thedeck and at 100 mm maximum forward of the centre of the hole of the shroud
plates, to lead the spinnakers sheets aft.

(e)

One device on each side of the boat for securing the spinnaker halyard w hilethe spinnaker is not set(f)Tubular covers at the lower end of shrouds or their adjusters and one for the
low er end of the forestay to ease the passage of the sheets and to prevent
snagging.

(g)

Stainless steel springs under blocks to prevent them from falling over.

(h)One non-electrical w ind indicator at the m ast head.

(i)

Sealing strips for the centreboard slot of optional material.

(k)

Strips of a minimum length of 300mm to reduce friction and/or the distance
betw een the centreboard and centreboard case, but no device shall be
attached to the inside of the centreboard case that could cause thecentreboard to gybe (angle to w indward).

(l)

A moulded insert in the thw art or a device to secure the spinnaker pole in the
cockpit.

(m)

Headsail tack adjustment system, consisting of a shackle on the stemhead
fitting, one cleat w ithout moving parts mounted on the foredeck, one fairlead
directly behind the cleat and a single piece of rope.

(n)

One Cunningham control system of rope w ith a maximum of tw o singlesheave blocks. One cleat w ithout moving parts and one guiding block directly
behind the cleat for the mainsail Cunningham line on the centerboard casecapping.

2011 International 420 Class Rules 23rd September. 2010

19

D.5

HULL WEIGHTThe hull weight, including stem head fitting, shroud plates w ithout shroud adjusters, allfixed fittings, complete hiking straps, rudder pintles or gudgeons, bailer, mainsheet
track/bar, centreboard pivot pin, inspection hole covers, spinnaker bags and corrector
weights, but excluding the, m ast, boom , spinnaker pole, centreboard, the control
lines, sheets, the rudder, portable equipment and the tow ing rope shall be 80 kg
minimum in dry condition.

D.6

HULL CORRECTOR WEIGHTS
If the hull weight according to D.5 is found to be less than 80 kg, corrector weights ofa maximum total w eight of 2 kg shall be bolted to the upper inside surface of thetransom. The number and total of correctors shall be recorded on the IMF and themeasurement certificate. Corrector weights shall not be removed or altered w ithout
the hull being re-w eighted by an official measurer.

2011 International 420 Class Rules 23rd September. 201020

Section E - CENTREBOARD, RUDDER AND TILLER
E.1

MEASUREM ENT
Centreboard and rudder shall comply w ith the current class rules.

E.2

CENT REBOARD

E.2.1

The centreboard shall be of even thickness, minimum 16 mm and maximum 20 mm
throughout, except that it may be bevelled to a maximum distance of 105 mm from theedges. Except for permitted bevelling, the thickness shall not vary by more than 1 mm.

E.2.2

The centreboard shall be made from one or a combination of the follow ing materials;
wood, plywood, polyester resin reinforced w ith glass fibre, epoxy reinforced w ith glass
fibre and/or plastic foam w hich includes micro-balloons and may be painted.

E.2.3

The profile of the centreboard shall conform to the dimensions and tolerances
specified on the measurement diagrams 13 & 14.
Lines (OA) and (OE) build the reference axes for length and w idth respectively, andshall be square to each other. Point (O) is the origin for both axes.
The contour of the centreboard is defined by the points A, origin O, E, G, the lines(GH) and (AI)Diagram 13
Point A is on the X axis, 910mm from origin.
Point B is on the X axis, 85mm from origin.
Point C is on the Y axis, 85mm from origin.
The centreboard shall alw ays touch points A, B and C, w hich are integral to it.
Point F is the point on the trailing edge 85mm from axis Y.
Point G is on the trailing edge at 995mm from Y axis.
Point E is the extension of the trailing edge (FG) on the Y axis.
Point D is the point on the low er edge 85mm from point E, measured along axis Y. It
shall be not more than 2mm from axis Y.
The trailing edge ( FG) is parallel to the x–axis: the distance of point (G) from theoutmost point of the leading edge, measured along y-axis, shall be equal to w idth (OE)within 2mm. At no point the w idth of the centreboard shall be more than 425mm or lessthan 415mm.

2011 International 420 Class Rules 23rd September. 201021

minimummaximum
Distance from the centre of the pivot hole to the x–axis
75 mm
85 mm
Distance from the centre of the pivot hole to the y–axis
910 mm
930 mmDistance from E to the x–axis
415 mm
425 mmTotal (positive, negative or both) deviation of an edge from a straight line:
Betw een points A and B from the x–axis........................................... ..............2 mm
Betw een points C and D from line ( CD) ............................................ ..............2 mm
Betw een points F and G from line ( FG) ............................................. ..............2 mm
Point I is on the X-axis. Lines (AI) and (GH) are parallel. The profile of the centreboard
inside area HGA I is free, but no part of it shall lay outside this area.
The shape of the low er corners of the centreboard shall lie w ithin the shaded areas indiagram 14, and no part of the bottom edge of the centreboard shall lie outside thepolygon formed betw een points B, B’, C’, D’, F’ and F.
Point B’ is the point on the x-axis 45mm from or igin O.
Point C’ is the point on the y-axis 45mm from origin O.
Point D’ is the point on the y-axis 45mm from point E.
Point F’ is the point on line ( EG), 45mm from point E.

Diagram 14

E.2.4

Only the follow ing fittings are permitted:(a) One centreboard uphaul of rope and/or elastic using a maximum of three singlesheave blocks and tw o cleats w ithout moving parts. A cleat w edge is permitted undereach cleat, and a fairlead in front of/or integral to the cleat.
(b) One centreboard downhaul of rope and/or elastic, one bush and/or one cleat
without moving parts on the centreboard case capping. A w edge is permitted under thecleat.

E.2.5

The direction of the control ropes used for the adjustment of the centreboard shall be
modified only by means of the blocks and the bush specified in rule E.2.4.

E.3

RUDDER

E.3.1

The profile of the rudder blade shall conform to the dimensions and tolerances
specified on the Diagram 15 (same as the official 420 rudder blade draw ing - August
2000)

2011 International 420 Class Rules 23rd September. 2010

22

212

R U DD ER PIVO T H O L E SH AL L BE
PL AC ED SO T H AT M AX IM U M D EPT H
O F BL AD E C O M PL I ES W I T H R U L E E.4 .4

A

A'
285
10
10

R 400

M IN IM U M L IN E

665
610

M AXIM U M L IN E

R 790

T H E R U D D ER SH AL L
BE B ET W EEN T H E M IN IM U M

435
AN D M AXIM U M L IN ES

R 420
240
115

R 70

Diagram 15
E.3.2

The rudder blade shall be of even thickness, minimum 16 mm and maximum 20 mm
throughout, except that it may be bevelled to a maximum distance of 105 mm from theedges. Except for permitted bevelling, the thickness shall not vary by more than 1 mm.

E.3.3

The rudder stock shall be made of aluminium alloy and/or stainless steel and the tillerof w ood or aluminium alloy. Str ips of any mater ial may be added to reduce friction
and/or the distance betw een the rudder stock and rudder blade. The rudder stock
shall not act as an extension of the hull. The rudder blade shall be made of one or a
combination of the follow ing materials; w ood, plywood, polyester with glass fibre,
epoxy w ith glass fibre and/or plastic foam, w hich includes micro-balloons and may be
painted.

E.3.4

Only the follow ing fittings are permitted:

E.3.5

(a)

One rudder dow nhaul made of one stainless steel w ire and/or rope andelastic and one cleat w ithout moving parts on the tiller (a w edge under thecleat is per mitted), or a pin or bolt through the rudder head and rudder
blade to hold the rudder blade dow n.

(b)

One tiller extension, w hich may be telescopic and of any mater ial.

(c)

One universal joint betw een tiller and extension.

A safety device shall be fitted so that the rudder cannot separate from the hull if theboat capsizes.

2011 International 420 Class Rules 23rd September. 201023

Section F - RIG
F.1

MEASUREM ENT
Measurement shall be carried out in accordance w ith the ERS.

F.2

MAST

F.2.1

MEASUREM ENT
The m ast and its fittings shall comply w ith the current class rules.

F.2.3

MANUFACTURER
Manufacturer is optional.

F.2.4

MATERIALS
The m ast spar shall be of aluminium alloy. It may be anodised or painted.

F.2.5

CONSTRUCTION
The m ast shall include a fixed sail groove or track, w hich may or may not be integral to
the spar but shall be of aluminium. Rotating and per manently bent m asts areprohibited but a m ast spar curvature measured at any place of the m ast between theupper and lower points, of a maximum of 40 mm is permitted.

F.2.6

FITTINGS
The follow ing fittings are mandatory and shall be used as specified:

F.2.6.1

A m ast head fitting w hich may include the upper sheave for the mainsail halyard.

F.2.6.2

One halyard for the mainsail, one halyard for the headsail and one halyard for the
spinnaker. The end of the spinnaker halyard may be fitted w ith an elastic cord. The
direction of the halyards shall be modified only by means of the blocks, sheaves orfairleads specif ied in Section F of the class rules.

F.2.6.3

One lock near the masthead or one lock, cleat or rack below the gooseneck for themainsail halyard.

F.2.6.4

A maximum of tw o blocks, sheaves, or fairleads for each halyard (mainsail, headsail,spinnaker). These blocks or sheaves shall be fixed on the spar.

F.2.6.5

The upper headsail halyard sheave, block or fairlead shall be located below theforestay rigging point and shall be positioned so that the intersection of the m ast andthe low er edge of the halyard, w hen at 900 to the m ast, and extended as necessary,
shall be at the distance stated in F.2.7 (see headsail hoist height).

F.2.6.6

No part of the upper spinnaker halyard sheave, block or fairlead shall be more than 40
mm from the foreside of the m ast.

F.2.6.7

Tw o shrouds, one forestay and tw o trapeze w ir es and the fittings to secure them to them ast. The positions of rigging points of the shrouds, forestay and trapeze w ir es shallbe at the distances mentioned in F.2.7 (see shrouds, forestay and trapeze heights).

F.2.6.8

A pair of fixed or adjustable metal spreaders, w ith optional attachment systems. The
spreader height shall be at the distance stated in F.2.7. Optional devices may be
attached to the spreaders and/or the rigging to prevent the spinnaker halyard fromgetting tangled.

F.2.6.9

One spinnaker pole fitting on the foreside of the m ast, with a maximum projection of
45mm.

F.2.6.10

One gooseneck, fixed to the m ast to connect the boom to the m ast.

2011 International 420 Class Rules 23rd September. 201024

F.2.6.11

One cleat w ithout moving parts below the gooseneck and one rope, for the mainsail
Cunningham line if the system in D.4.2.3(n) is not present.

F.2.6.12

A tensioning system for the headsail halyard made of tw o blocks w ith a maximum of six
sheaves in total, and one cleat. This cleat may have moving parts and shall be fixed at
one of the two blocks. The system shall be attached via a hook or a shackle to theheadsail halyard, and at the other end to the m ast or the mast step fitting, by means of
a w ire strop or shackles and an attachment to the m ast (tang, mast anchor plate etc).
Enclosed purchase systems such as power boxes are not permitted.

F.2.6.13

One rope or a device around the m ast and through the mainsail tack cringle to secure
the mainsail tack.

F.2.6.14

A protection around the m ast where it touches the m ast gate

F.2.6.15

One spinnaker pole uphaul / dow nhaul made of rope and elastic and one hook. The
spinnaker pole uphaul / downhaul may be fitted with two plastic balls. For the
adjustment of the spinnaker pole uphaul / dow nhaul, only the follow ing fitting ispermitted, one eye or block on the foreside of the m ast, located below the forestay andshroud attachment. One eye or block or one hole/bush in the m ast partner at theforeside of the mast at the level of the mast partner. One block, sheave, or one
fairlead at the bottom of the m ast. (Additional fittings for the spinnaker pole
uphaul/dow nhaul are stated in D.4.2.2.(j)).

F.2.6.16

One kicking-strap attachment fitting

F.2.6.17

A m ast heel fitting w hich may include the low er sheaves for the halyards andspinnaker pole uphaul / dow nhaul.

F.2.6.18

Per manently painted / taped limit marks in a contrasting colour.

F.2.6.19

A device for preventing the mainsail from being set above the upper point, to ensurecompliance w ith C.10.3.2.2

F.2.7

DIM ENSIONS
Unless otherw ise specif ied, all longitudinal measurements shall be carried out from them ast datum point. For this purpose, the m ast datum point (MDP) is located at them ast heel point.
m inimum
Mast length
Fore and aft m ast spar cross section betw een 1550
mm and 4500 mm from the MDP
Transverse m ast spar cross section within 4500 mm
from MDP
Mast lim it m arks w idth
Lower point height
Upper point height from lower point
Headsail Hoist HeightSpinnaker hoist height
Shrouds, forestay and trapeze heights
Spreader height

F.2.8

F.2.9

50 mm

m axim um
6260 mm
75 mm

45 mm

75 mm

10 mm

4520 mm
4550 mm2550 mm1160 mm
4900 mm(see F.2.6.5)
4650 mm
4650 mm2650 mm

WEIGHT
The m ast weight, w ith fittings specified in F.2.6 but w ithout the tensioning system
mentioned in F.2.5.12 and the rope mentioned in F.2.5.13, and including fittings
specified in F.5.1 w ithout the elastic cord and the four fairleads stated in F.5.1.2 andwith the length of elastic at the level of the spreaders as stated in F.5.1.2, shall be notless than 7.5 kg.
The centre of gravity of the m ast, including fittings and rigging listed in F.2.8 w ith the
shrouds, forestay, trapeze w ir es and halyards secured along the m ast, shall be at 2400

2011 International 420 Class Rules 23rd September. 201025

mm minimum from the m ast datum point. For the measurement, the halyards shall behoisted and the halyard tails outside the m ast shall be kept in hand by the measurer.
F.3

BOOM

F.3.1

MEASUREM ENT
The boom and its fittings shall comply w ith the current class rules.

F.3.2

MANUFACTURER
Manufacturer is optional.

F.3.3

MATERIALS
The boom spar shall be of aluminium alloy. It may be anodised or painted.

F.3.4

CONSTRUCTION

F.3.4.1

The boom shall include a fixed aluminium sail groove or track, w hich may or may not
be integral to the boom spar.

F.3.4.2

The boom spar shall be of the same cross section throughout and shall not betapered.

F.3.5

FITTINGS

F.3.5.1

MANDATORY

F.3.5.1.1

A kicking-strap attachment (eye, plate, or hole through the boom )F.3.5.1.2

Tw o mainsheet block attachments fittings (eyes, plates, or holes through the boom)

F.3.5.1.3

A gooseneck attachment

F.3.5.1.4

One end fitting w hich may incorporate one sheave. One outhaul consisting of rope, amaximum of one block, one cleat w ithout moving parts and optional elastic cord. A
guiding block directly behind the cleat may be used.
A device for preventing the mainsail from being set outside the outer point, to ensurecompliance w ith C.10.3.2.2

F.3.5.1.5
F.3.5.1.6

Per manently painted / taped outer lim it m ark in a contrasting colour.

F.3.5.2

OPTIONAL

F.3.5.2.1

Ropes or devices through the cringles and around the boom to secure the m ainsail atthe clew point and the tack point.

F.3.5.2.2

Protections w here the boom touches the shrouds, of any material ( maximum length /height / thickness = 100 mm /50 mm /5 mm)

F.3.6

DIM ENSIONS
Vertical boom spar cross section
Transverse boom spar cross section
Boom lim it m ark w idth
Outer point distance

F.4

SPINNAKER POL E

F.4.1

MEASUREM ENT

m inimum
55 mm
32 mm
10 mm

m axim um
89 mm
76 mm
2400 mm

The spinnaker pole and its fittings shall comply w ith the current class rules
F.4.2

MANUFACTURER
Manufacturer is optional

2011 International 420 Class Rules 23rd September. 201026

F.4.3

MATERIALS
The spinnaker pole spar shall be made of aluminium.

F.4.4

FITTINGS

F.4.5

Only the follow ing fittings are permitted:(a) End fittings and control line w hich may incorporate knots, toggles or shorttubes for easier handling.
(b) Fittings approximately at the mid point for attachment for uphaul/dow nhaul.
DIM ENSIONS
The maximum spinnaker pole length is 1750 mm.

F.5

RIGGING AND FITTINGS

F.5.1

RIGGING
The standing rigging shall comply w ith the current class rules. Certification is not
required. The follow ing rigging shall be used, and consist of only:

F.5.1.1
F.5.1.2

A forestay and one shroud on each side, to support the m ast. These shall be of steel
wire rope w ith a minimum diameter of 2 mm. Rod rigging is prohibited.
One steel trapeze w ir e, with a minimum diameter of 2 mm, on each side for the use of
one person only. Each trapeze adjustment system shall be provided w ith a maximum of
one handhold, tw o sheaves, rings or hooks, an elastic cord, one rope, and one cleat.
The trapeze w ires may be substituted w ith rope for a maximum length of 500mm fromthe handhold. The tw o trapezes shall be connected to the boat by elastic cord w ith amaximum of four fairleads as stated in D.4.2.2.(l). A length of elastic is permitted tokeep the trapeze w ir es clear of the spreaders. Self-tacking trapeze systems are notallow ed.

F.5.2

FITTINGS

F.5.2.1

Each shroud shall be attached to the shroud plates by means of plates having rows ofadjustment holes and pins. No other method of shroud adjustment is per mitted.

2011 International 420 Class Rules 23rd September. 201027

Section G – SAILS
G.1.

MEASUREM ENT

G.1.1

Measurement shall be carried out in accordance w ith the current ERS.

G.1.2

Unless otherw ise specif ied in these rules, sails shall comply w ith the current classrules.

G.2

CERTIFICATION

G.2.1

The official measurer shall certify mainsails and headsails at the tack, andspinnakers at the head, and shall sign and date the certification m ark. The mainsailand the spinnaker may be certified w ithout letters and numbers, but they shall comply
when racing w ith Class rule C.10.3.1 and C.10.5.1)

G.2.2

An ISAF In- House Certification (IHC) Authorizing Authority may appoint one or more
In-House Official Measurers at a sailmaker to measure and certify sails produced bythat manufacturer in accordance with the ISAF guidelines.

G.2.3

For the mainsail and jib, the w eight in g/m2 of the body of the sail shall be indelibly
marked near the head point by the sailmaker together w ith the date and his signatureor stamp.
G.2.4 SAILMAKER

R20

Sailmaker is optional.

R5
147

R20

G.3 MAINSAIL

45

17°

R5

R5
R5

R5

R20

R10

R5

R10
R10

R5
40

480

R20
R20

R20 R5
355
350
310
270

G.3.1
R5

R10

R5

R20

The 420 emblem shall be in dark
blue, positioned
below
and
adjacent to the top batten pocket
and conform to the dimensions
and requirements mentioned in the
diagram w ith a tolerance of ±2 mm(see diagram 16).
G.3.2

R5

R5

R5
115
120
135
160

CONSTRUCTION

G.3.2.1 The construction shall be:
Soft sail, single-ply sail.

190
150
40

R20

EMBL EM

R10
R35

220
235
265
280
335
380

G.3.2.2 The body of the sailshall consist of the same w hite
woven ply throughout except forthe panel adjacent to the foot,which may be of a different w ovenply. The ply fibres shall be ofpolyester. Batten pocket patches
may be made from a w oven ply of
less w eight than that of the body ofthe sail.

Diagram 16
G.3.2.3

The w eight of the ply of the body of the sail shall be a minimum of 150 g/m2.

G.3.2.4

The follow ing are permitted:
Stitching, glues, tabling, tapes, bolt ropes for the luff and the foot, one cringle/eye ateach sail corner, one headboard w ith fixings, one Cunningham eye, a rope for theCunningham, batten pocket patches, batten pocket elastic, one batten pocket end

2011 International 420 Class Rules 23rd September. 201028

cap and one batten tensioning device for the top batten pocket, one boom slide at theclew , tell tales, ICA sail button, sailmaker’s trade mar k, one w indow of single ply.
G.3.2.5

The ICA sail button shall be fixed in the tack.

G.3.2.6

The leech shall not extend aft of straight lines betw een:
(1) The aft head point and the intersection of the leech and the upper edge of thenearest batten pocket,(2) The intersection of the leech and the low er edge of a batten pocket and theintersection of the leech and the upper edge of an adjacent batten pocket below ,(3) The clew point and the intersection of the leech and the low er edge of thenearest batten pocket.

G.3.3

DIM ENSIONS (SEE DIAGRAM 17)
Minimum
Leech length
Quarter width
Half w idthThree-quarter width
Upper width at upper leech point(600 mm from the head point)
Top Width
Flutter patches reinforcement size
Chafing patches reinforcement size
Prim ary reinforcements
Secondary reinforcements
Batten pocket patches
Extension of the centreline of the top
batten pocket to the luff from the headpoint
Distance from the end of the upper
Batten pocket to the luff
Inside batten pocket length of lowermost
Inside batten pocket length of the twointer mediate
Inside Batten pocket w idth
Window Area
Window to the sail edge
Foot boltrope length for sails first certified
after 1st March 2003

Maxim um
5400 mm
2130 mm
1630 mm
995 mm
480 mm
115 mm
100 mm
900 mm
300 mm
900 mm
150 mm1420 mm1470 mm

20 mm
540 mm
700 mm
60 mm
0.3 m2150 mm1920 mm

The batten pocket position as s hown in diagram 17 s hall be m eas ured with theleech flattened by folding/flaking.

2011 International 420 Class Rules 23rd September. 2010

29

600

MAIN SAIL DIAGRAM

4801470 max
1220
1420 min995

The centres of batten
pockets shall be within
50mm of the points
shown

2220

700 max
1630
3220

5400 max

700 max

4220

2130

540 max

Diagram 17

2011 International 420 Class Rules 23rd September. 2010

30

G.4

HEADSAIL

G.4.1

CONSTRUCTION

G.4.1.1

The construction shall be: Soft sail, single-ply sail. The leech shall not extend
beyond a straight line betw een the aft head point and the clew point (i.e. shall not be
convex).

G.4.1.2

The body of the sail shall consist of the same w hite w oven ply throughout. The ply
fibres shall be of polyester.

G.4.1.3

The w eight of the ply of the body of the sail shall be 150 gr./m2 minimum

G.4.1.4

The follow ing are permitted : Stitching, glues, tapes, tabling, one cringle / eye at each
sail corner, one w indow of single ply, tell tales, a rope for the luff tension adjustment
and one cleat in the tack area, a steel w ire rope inside the luff sleeve, sail button,
sailmaker ’s trade mar k.

G.4.1.5

The sail button shall be fixed in the tack.

G.4.2

DIM ENSIONSLuff length
Leech length
Foot length
Foot median
Top w idth
Foot irregularity for sails first certified after 1st March 2010
Flutter patches reinforcement size
Chafing patches reinforcement size
Prim ary reinforcements
Secondary reinforcements
Window area
Window dimension

Maxim um
3500 mm3200 mm
1750 mm
3360 mm
40 mm
30 mm
100 mm
900 mm
300 mm
900 mm
0,1 m2
540 mmG.5

SPINNAKER

G.5.1

CONSTRUCTION

G.5.1.1

The construction shall be: Soft sail, single-ply sail. The sail shall be symmetricalabout its centreline. The colour of any tabling and reinforcement is optional.

G.5.1.2

The body of the sail shall consist of the same woven ply throughout. The ply fibres
shall be of polyester or polyamide.

G.5.1.3

The follow ing are permitted: Stitching, glues, tapes, corner eyes, tell tales, sail button,
sailmaker ’s mar k.

G.5.1.4

The sail button shall be fixed in the head.

G.5.2

DIM ENSIONS
Leech Length
Foot Length
Half Width
Prim ary Reinforcements
Secondary Reinforcements
Foot Median for sails first certified after 15th March 20072011 International 420 Class Rules 23rd September. 2010

Maxim um
4000 mm
2220 mm2840 mm
300 mm
900 mm4650 mm31

__________________________________________________________________OFFICIAL DOCUM ENTS:
International 420 Class Rules
Lines plan ( Plan de formes) issue C (August 2004)
Building specification (Draw ing N° 5) issue H (February 2009)
International 420 Rudder Blade Draw ing (August 2000)
International Measurement For m (January 2010)
Official templates used for measurement:
BOW ( ISSUE C); C1 ( ISSUE B); C2 ( ISSUE B); C3 ( ISSUE B); C4 (ISSUE B); C5 (ISSUE B); C6(ISSUE B); C7 ( ISSUE B); C8 ( ISSUE B); C9 ( ISSUE B); C10 ( ISSUE B) AND STERN ( ISSUE Bor C).

Effective Date:
Published Date:

24th September 2010
17th September 2010

Previous issue:

8th February 20102011 International 420 Class Rules 23rd September. 201032