EN ISO 11812:2018

Small craft - Watertight cockpits and quick-draining cockpits (ISO 11812:2001)

This International Standard specifies requirements for cockpits and recesses to be designated either as "watertight"
or as "quick-draining" on small craft of hull length up to 24 m.
It does not set requirements for the size and shape of a cockpit or recess, nor when or where it shall be used. It
only considers draining by gravity, and not by pumping or other methods.
NOTE 1 The term "quick-draining cockpit" has been chosen to differentiate from the common understanding of "self-draining
cockpit" where water may be drained overboard in certain conditions, but without specified draining speed, height of bottom or
sill, etc.
NOTE 2 Examples of single-plane cockpit bottoms are given in informative annex A.

Kleine Wasserfahrzeuge - Wasserdichte und schnell-lenzende Plichten (ISO 11812:2001)

Petits navires - Cockpits étanches et cockpits rapidement autovideurs (ISO 11812:2001)

La présente Norme internationale spécifie les exigences applicables aux cockpits et aux cavités pour qu'ils soient
qualifiés soit d'«étanches», soit de «rapidement autovideurs», sur les navires de longueur de coque inférieure ou
égale à 24 m.
Elle n'établit aucune exigence relative à la taille ou à la forme des cockpits ou des cavités, ni ne spécifie quand et
où ils doivent être utilisés. Elle prend en compte uniquement la vidange par gravité et non par pompage ou par
d'autres méthodes.
NOTE 1 Le terme «cockpit rapidement autovideur» a été choisi pour marquer la différence avec la notion habituelle de
«cockpit autovideur» où l'eau peut être évacuée à l'extérieur dans certaines conditions, mais sans spécification sur la vitesse de
vidange, la hauteur du fond ou des surbaux, etc.
NOTE 2 Des exemples de fond de cockpit en un seul plan sont donnés dans l'annexe informative A.

Mala plovila - Vodotesni krmarjevi prostori in krmarjevi prostori s hitrim odvodnjavanjem (ISO 11812:2001)

Ta mednarodni standard določa zahteve za krmarjeve prostore in kabine, ki so označeni kot »vodotesni« ali kot »s hitrim odvajanjem« v malih plovilih z dolžino trupa do 24 m.
Ne določa zahtev glede velikosti in oblike krmarjevega prostora/kabine ali glede časa/načina njegove/njene uporabe. Obravnava odvodnjavanje zgolj na podlagi težnosti in ne na podlagi črpanja ali drugih metod.
OPOMBA 1: Izraz »krmarjevi prostori s hitrim odvodnjavanjem« je bil izbran za namene razlikovanja od splošnega izraza »krmarjevi prostori s samodejnim odvodnjavanjem«, pri katerem se voda v nekaterih pogojih lahko odvaja čez krov, vendar brez opredeljene hitrosti odvajanja, višine dna ali praga itd.
OPOMBA 2: Primeri enodelnega dna krmarjevih prostorov so podani v informativnem dodatku A.

General Information

• Status: Withdrawn
• Publication Date: 25-Sep-2018
• Withdrawal Date: 13-Apr-2025
• ICS: 47.080 - Small craft
• Technical Committee: CEN/TC 464 - Small Craft
• Drafting Committee: CEN/TC 464 - Small Craft
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 25-Sep-2024
• Completion Date: 14-Apr-2025
• Directive: 2003/44/EC - Approximation of the laws, regulations and administrative provisions of the Member States relating to recreational craft
• Directive: 2013/53/EU - Directive 2013/53/EU of the European Parliament and of the Council of 20 November 2013 on recreational craft and personal watercraft and repealing Directive 94/25/EC
• Mandate: M/542 - [C(2015)8736] Standardisation Request to the European Committee for Standardisation and the European Committee for Electro-technical Standardisation as regards recreational craft and personal watercraft in support of Directive 2013/53/EU of the European Parliament and of the Council of 20 November 2013 on recreational craft and personal watercraft and repealing Directive 94/25/EC.
• Ref Project: SIST EN ISO 11812:2018 - Small craft - Watertight cockpits and quick-draining cockpits (ISO 11812:2001)

Relations

• Replaces: EN ISO 11812:2001 - Small craft - Watertight cockpits and quick-draining cockpits (ISO 11812:2001)
• Effective Date: 03-Oct-2018
• Replaced By: EN ISO 11812:2024 - Small craft - Watertight or quick-draining recesses and cockpits (ISO 11812:2020)
• Effective Date: 18-Jan-2023
• Revised: FprEN ISO 11812 - Small craft - Watertight or quick-draining recesses and cockpits (ISO/FDIS 11812:2019)
• Effective Date: 07-Jun-2017

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2018
1DGRPHãþD
SIST EN ISO 11812:2002
Mala plovila - Vodotesni krmarjevi prostori in krmarjevi prostori s hitrim
odvodnjavanjem (ISO 11812:2001)
Small craft - Watertight cockpits and quick-draining cockpits (ISO 11812:2001)
Kleine Wasserfahrzeuge - Wasserdichte und schnell-lenzende Plichten (ISO
11812:2001)
Petits navires - Cockpits étanches et cockpits rapidement autovideurs (ISO 11812:2001)
Ta slovenski standard je istoveten z: EN ISO 11812:2018
ICS:
47.080 ýROQL Small craft
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 11812
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2018
EUROPÄISCHE NORM
ICS 47.080 Supersedes EN ISO 11812:2001
English Version
Small craft - Watertight cockpits and quick-draining
cockpits (ISO 11812:2001)
Petits navires - Cockpits étanches et cockpits Kleine Wasserfahrzeuge - Wasserdichte und schnell-
rapidement autovideurs (ISO 11812:2001) lenzende Plichten (ISO 11812:2001)
This European Standard was approved by CEN on 16 April 2018.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11812:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of Directive 2013/53/EU aimed to be covered . 4

European foreword
The text of ISO 11812:2001 has been prepared by Technical Committee ISO/TC 188 “Small craft” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 11812:2018.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by March 2019, and conflicting national standards shall be
withdrawn at the latest by March 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 11812:2001.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive 2013/53/EU.
For relationship with EU Directive 2013/53/EU, see informative Annex ZA, which is an integral part of
this document.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
the United Kingdom.
Endorsement notice
The text of ISO 11812:2001 has been approved by CEN as EN ISO 11812:2018 without any modification.
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of Directive 2013/53/EU aimed to be covered
This European standard has been prepared under a Commission’s standardization request M/542
C(2015) 8736 final to provide one voluntary means of conforming to Essential Requirements of Directive
2013/53/EU.
Once this standard is cited in the Official Journal of the European Union under that Directive, compliance
with the normative clauses of this standard given in Table ZA.1 confers, within the limits of the scope of
this standard, a presumption of conformity with the corresponding Essential Requirements of that
Directive and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and Annex I of Directive
2013/53/EU
Essential Clause(s)/sub- Remarks/Notes
Requirements of clause(s) of
Directive this EN
2013/53/EU
Annex I, Part A, 3.5 – All Clauses, except 3.1 This Standard deals with cockpits and recesses that are
Flooding drained by gravity; it does not deal with removal of water
Annex B
by pumps or other means.
Annex C
Annex D
The design category sea and wind conditions given in clause
Annex E
3.1 of this Standard no longer apply.

The design category parameters set out in EN ISO 12217-
1:2015, Table 6 or EN ISO 12217-2:2015, Table 11 equate
to design categories A, B, C and D of Directive 2013/53/EU
and shall be applied when required.

Annex I, Part A, 2.5 – 10 In respect of information required to document a cockpit as
Owner’s Manual watertight (clause 5.2) or quick draining (clause 5.3) in the
Owner’s Manual.
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European Union.
WARNING 2 — Other Union legislation may be applicable to the product(s) falling within the scope of
this standard.
INTERNATIONAL ISO
STANDARD 11812
First edition
2001-12-15
Small craft — Watertight cockpits and
quick-draining cockpits
Petits navires — Cockpits étanches et cockpits rapidement autovideurs

Reference number
ISO 11812:2001(E)
©
ISO 2001
ISO 11812:2001(E)
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ii © ISO 2001 – All rights reserved

ISO 11812:2001(E)
Contents Page
Foreword.v
Introduction.vi
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Symbols.5
5 General requirements.6
5.1 Loading and measurement conditions.6
5.2 Requirements for “watertight” cockpits and recesses .6
5.3 Requirements for “quick draining” cockpits and recesses.7
5.4 Closing appliances.7
6 Requirements for quick-draining cockpit bottom .7
6.1 Minimum cockpit bottom height, H .7
B,min
6.2 Exception to 6.1 for recesses or lockers.8
6.2.1 Exception up to 10 % of cockpit bottom area.8
6.2.2 Lockers in the cockpit bottom .8
7 Requirements for drainage of quick-draining cockpits.8
7.1 Cockpit drainage.8
7.1.1 General.8
7.1.2 When the boat is upright.8
7.1.3 When the boat is heeled.8
7.2 Draining time.9
7.3 Number of drains .10
7.4 Minimum drain dimensions .10
7.4.1 Internal dimensions of the drain .10
7.4.2 Eventual protective grids.10
7.5 Centreboard housings and other types of drain .10
7.6 Drain fitting.11
7.7 Drain piping design and construction.11
7.8 Draining time assessment .11
7.8.1 General.11
7.8.2 Measurement of the draining time .11
7.8.3 Calculation of the draining time.12
7.8.4 Quick method of calculation for cockpit fitted with two drains.12
8 Requirements for sills.14
8.1 Sill height for watertight cockpits.14
8.2 Sill height and other requirements for quick-draining cockpits.14
8.2.1 Sill-height measurement.14
8.2.2 Requirements for sill height of quick draining cockpits .14
8.2.3 Requirements for companionway doors and appliances above sill height .14
8.2.4 Other requirements.15
9 Watertightness requirements.15
9.1 Watertightness requirements of watertight cockpits .15
9.2 Watertightness requirements of quick-draining cockpits.15
9.2.1 Watertightness of the cockpit .15
9.2.2 Permanently open ventilation openings .16
10 Owner’s manual — Documentation.16
ISO 11812:2001(E)
Annex A (informative) Examples of single-plane cockpit bottoms.17
Annex B (normative) Analysis of multi-level cockpit bottom.19
Annex C (normative) Draining time calculation using tables.26
Annex D (normative) Alternative method of calculation — Direct calculation with head losses .30
Annex E (normative) Watertightness tests.33
Bibliography .36

iv © ISO 2001 – All rights reserved

ISO 11812:2001(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 11812 was prepared by Technical Committee ISO/TC 188, Small craft.
Annexes B, C, D and E form a normative part of this International Standard.
Annex A is for information only.
ISO 11812:2001(E)
Introduction
The compliance to this International Standard may not be required to show that a boat fulfils the essential safety
requirements of the Directive 94/25/EC, but it may be required by ISO 12217.

vi © ISO 2001 – All rights reserved

INTERNATIONAL STANDARD ISO 11812:2001(E)

Small craft — Watertight cockpits and quick-draining cockpits
1 Scope
This International Standard specifies requirements for cockpits and recesses to be designated either as “watertight”
or as “quick-draining” on small craft of hull length up to 24 m.
It does not set requirements for the size and shape of a cockpit or recess, nor when or where it shall be used. It
only considers draining by gravity, and not by pumping or other methods.
NOTE 1 The term “quick-draining cockpit” has been chosen to differentiate from the common understanding of “self-draining
cockpit” where water may be drained overboard in certain conditions, but without specified draining speed, height of bottom or
sill, etc.
NOTE 2 Examples of single-plane cockpit bottoms are given in informative annex A.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
1)
ISO 8666:— , Small craft — Principal data
ISO 9093-1:1994, Small craft — Seacocks and through-hull fittings — Part 1: Metallic
1)
ISO 9093-2:— , Small craft — Seacocks and through-hull fittings — Part 2: Non-metallic
1)
ISO 12216:— , Small craft — Windows, portlights, hatches, deadlights and doors — Strength and tightness
requirements
1)
ISO 12217-1:— , Small craft — Stability and buoyancy assessment and categorization — Part 1: Non-sailing
boats of hull length greater than or equal to 6 m
1)
ISO 12217-2:— , Small craft — Stability and buoyancy assessment and categorization — Part 2: Sailing boats of
hull length greater than or equal to 6 m
1)
ISO 12217-3:— , Small craft — Stability and buoyancy assessment and categorization — Part 3: Boats of hull
length less than 6 m
1) To be published.
ISO 11812:2001(E)
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
design categories
description of the sea and wind conditions for which a boat is assessed to be suitable
NOTE The following design categories apply:
 A: Ocean: Designed for extended voyages where conditions may exceed wind force 8 (Beaufort scale) and significant
wave heights of 4 m and above, and vessels largely self-sufficient; but excluding abnormal conditions such as hurricanes.
 B: Offshore: Designed for offshore voyages where conditions up to and including wind force 8 and significant wave
heights up to and including 4 m may be experienced;
 C: Inshore: Designed for voyages in coastal waters, large bays, estuaries, lakes and rivers where conditions up to and
including wind force 6 and significant wave heights up to and including 2 m may be experienced;
 D: Sheltered waters: Designed for voyages in close coastal waters, small bays, lakes, rivers and canals where conditions
up to and including wind force 4 and maximum wave heights up to and including 0,3 m may be experienced.
3.2
length of hull
L
H
length of the hull according to ISO 8666
NOTE Length of hull is expressed in metres.
3.3
maximum beam
B
max
overall beam of monohull or multihull craft according to ISO 8666
NOTE Maximum beam is expressed in metres.
3.4
waterline
WL
waterline in the fully loaded ready-for-use condition
3.5
freeboard amidships
F
M
freeboard at mid-waterline in fully loaded ready-for-use condition according to ISO 8666
3.6
sailing boat
boat designed to use sails as its primary means of propulsion, as defined in ISO 12217-2
3.7
non-sailing boat
boat not designed to use sails as primary means of propulsion, as defined in ISO 12217-1
3.8
cockpit and recess
any area that may retain water, however briefly, due to rain, waves, boat heeling, etc.
2 © ISO 2001 – All rights reserved

ISO 11812:2001(E)
NOTE Cockpits are normally designed for accommodation of people but, for the purpose of this International Standard, the
term "cockpit” will be used either for a proper cockpit or for any recess. This means that
 bulwarks may create a large cockpit,
 open boats may effectively comprise a cockpit which includes nearly all the boat,
 cockpit(s) may be situated anywhere in the boat, and
 a cockpit may open aft to the sea.
3.9
watertight cockpit or recess
cockpit or recess which satisfies the requirements of this International Standard for watertightness and sill heights,
but not those for drainage
3.10
quick-draining cockpit or recess
cockpit with characteristics and draining capacity which fulfil all the requirements of this International Standard for
one or several design categories
NOTE According to its characteristics, a cockpit may be considered quick-draining for one design category, but maybe not
for a higher category.
3.11
cockpit sole
essentially horizontal surface(s) of the cockpit on which people normally stand
3.12
cockpit bottom
lowest surface of the cockpit sole where water collects before being drained
NOTE 1 Devices raising the standing level(s) from the rigid part of the cockpit sole, e.g. grating, stands, bridge decks, are not
considered as part of the cockpit bottom.
NOTE 2 The cockpit bottom is considered to comprise only one plane. A cockpit bottom with several levels is considered
according to annex B.
3.13
bridge deck
area just outside the companionway opening and above the cockpit bottom, onto which people normally step
before entering the accommodation
3.14
closing appliance
device used to cover an opening in the cockpit, hull or superstructures
EXAMPLE Hatch, window, door, engine cover, etc.
3.15
cockpit water-retention height
h
C
height of the water contained in the cockpit measured between the cockpit bottom and the point of overflow
outboard, the boat being upright, at rest and fully loaded
NOTE 1 This height corresponds to the lowest point where the overflow area, expressed in square metres, is
> 0,005 L B , and is usually the lowest point of the cockpit coaming.
H max
NOTE 2 For assessing h , every closing appliance, including the companionway door(s) is assumed to be closed.
C
ISO 11812:2001(E)
3.16
cockpit bottom height
H
B
height of the cockpit bottom above the waterline, the boat being upright, at rest and fully loaded
NOTE For a single-plane cockpit bottom, H is measured at the centre of surface of this plane. For a multi-plane bottom, H
B B
is measured according to annex B.
3.17
minimum cockpit bottom height
H
B,min
minimum value of H required by this International Standard
B
3.18
drain
outlet of the cockpit enabling any water contained to be discharged outboard by gravity
NOTE A drain can be
 a pipe discharging overboard above or below the waterline,
 a part of the cockpit allowing direct discharge overboard,
 scuppers and freeing port,
 etc.
3.19
companionway opening
opening giving way to accommodation
NOTE There may be several companionway openings.
3.20
companionway door
door or closing appliance intended to close a companionway opening
3.21
washboards
closing appliance for companionway opening made of several mobile boards that, when closed, are stacked one on
top of each other
NOTE 1 This is a very frequent device on sailing monohulls.
NOTE 2 Boards are added as the weather worsens to constitute a higher sill.
3.22
sill
barrier above which water in the cockpit may enter companionway openings and downflood the boat
NOTE The lids to cockpit lockers or any opening other than the companionway opening, and leading into non-quick-draining
parts of the boat are not considered to be sills if the closing appliance covering them fulfils the watertightness requirements of
clause 9.
3.23
fixed sill
sill being a fixed, integral and permanent part of the cockpit
4 © ISO 2001 – All rights reserved

ISO 11812:2001(E)
3.24
semi-fixed sill
any closing appliance movable but permanently attached to the boat which, when in place, constitutes a sill higher
than the fixed sill
EXAMPLE Sliding or hinged doors, hatches, sliding sills, but excluding washboards.
NOTE A lanyard is not regarded as a permanent attachment.
3.25
sill height
h
s
height of sill, either the top of a fixed sill, or of the mobile part, when closed, for a semi-fixed sill
3.26
minimum sill height
h
s,min
minimum value of sill height required by this International Standard
3.27
cockpit volume
V
C
volume, in cubic metres, of water that can be instantaneously contained in the cockpit before discharge, which is
the volume below h
C
3.28
cockpit volume coefficient
k
C
ratio between the cockpit volume and the reserve buoyancy
V
C
k =
C
LBF
Hmax M
3.29
degree of watertightness
ability of a closing appliance, fitting or surface, to resist ingress of water according to the conditions of protection
from water
NOTE The degreee of water tightness is summarized as follows.
Degree 1 Degree of tightness providing protection against effects of continuous immersion in water.
Degree 2 Degree of tightness providing protection against effects of temporary immersion in water.
Degree 3 Degree of tightness providing protection against splashing water.
Degree 4 Degree of tightness providing protection against water drops falling at an angle of up to 15° from the vertical.
4 Symbols
Table 1 summarizes the main symbols used in this International Standard.
ISO 11812:2001(E)
Table 1 — Summary of symbols
Symbol Unit Meaning Subclause or annex
concerned
B
m Maximum beam 3.3, 3.28
max
C — Draining-time reduction coefficient Annex C
C — Loss coefficient for discharge above the waterline Annex C
C — Loss coefficient for discharge below the waterline Annex C
d mm Drain diameter in millimetres 7.8, annexes B,C,D
D m Drain diameter in metres Annex D
F
m Freeboard amidships 3.5, 3.28
M
3.15, 7.2, 8.1, 9.1,
h m Cockpit water-retention height
C
annexes A, B, C ,D
H m Cockpit bottom height above the waterline 3.16, 6.1, annex B
B
H
m Minimum cockpit bottom height above the waterline 3.17, 6.1, 7.6, annex B
B,min
h m Sill height 3.25, 8.2, 9.2, annex B
S
h m Required minimum sill height 3.26, 8.2, 9.2, annex B
S,min
k — Cockpit volume coefficient 3.28, 7.2
C
L m Length of hull 3.2, 3.28
H
t min Maximum allowable draining time 7.2, 7.8, annexes B,C,D
max
t min Reference draining time = t /V 7.8, annexes B, C
ref max C
V Cockpit volume 3.27, 3.28, 7.2
m
C
NOTE Heights measured above the cockpit bottom have symbols beginning with h, whereas heights measured above the waterline
have symbols beginning with H.

5 General requirements
5.1 Loading and measurement conditions
The loading conditions for the subclauses 5.2 to 5.4 are “fully loaded ready-for-use” as defined in ISO 8666. In
some cases, the mass of water contained in specific volumes shall be added to this loading (see 6.2.1 and 6.2.2).
The measurement or calculations shall be made with the boat upright and at rest in smooth water.
NOTE This loading condition is surpassed and maybe the trim altered when the cockpit is in its draining period, i.e. when
partially or totally filled with water.
5.2 Requirements for “watertight” cockpits and recesses
A “watertight” cockpit or recess shall
 have its sills in accordance with clause 8, and
 show a degree of watertightness in accordance with clause 9.
6 © ISO 2001 – All rights reserved

ISO 11812:2001(E)
5.3 Requirements for “quick draining” cockpits and recesses
A “quick-draining” cockpit or recess shall
 have its bottom height H above the the waterline in accordance with clause 6;
B
 have its draining devices in accordance with clause 7;
 have its sills in accordance with clause 8;
 show a degree of watertightness in accordance with clause 9.
For simplicity, the main part of this International Standard considers cockpits having only one bottom level.
Cockpits having several bottom levels shall be analysed according to annex B.
Figure 1 gives schematically the principal heights used in this International Standard for a one-level bottom cockpit.

a) Case of a semi-fixed sill b) Case of a fixed sill
Key
1 Waterline 7 Access companionway
2 Cockpit bottom 8 Top of the fixed part
3 Overflow point 9 Top of the mobile part
4 Coamings 10 Top of fixed sill
Chambers and compartments
5 Seats 11 Companionway closed by washboards
6 Drain
a
H and h measured at the centre of the cockpit bottom
B C
Figure 1 — Schematic longitudinal section of a cockpit
5.4 Closing appliances
Closing appliances fitted in watertight cockpits and quick-draining cockpits, and giving access to the interior of the
boat, shall fulfil the requirements of ISO 12216 and of clause 9.
6 Requirements for quick-draining cockpit bottom
6.1 Minimum cockpit bottom height, H
B,min
The minimum cockpit bottom height, H , above the the waterline shall be according to Table 2.
B,min
ISO 11812:2001(E)
Table 2 — Minimum height, H , of the cockpit bottom

B,min
Dimensions in metres
Design category Height, H
B,min
A 0,15
B
0,1
C 0,075
D 0,05
NOTE Greater heights than these minimum values may be required to
fulfil the maximum acceptable draining time according to 7.2

6.2 Exception to 6.1 for recesses or lockers
6.2.1 Exception up to 10 % of cockpit bottom area
Surfaces up to a total 10 % of the horizontal projection of the cockpit bottom are not required to comply with 6.1.
Among these surfaces, those containing water after the cockpit has drained will be considered full of water when
assessing the fully loaded condition.
6.2.2 Lockers in the cockpit bottom
Lockers placed in the cockpit bottom
 which are intended for the storage of liferafts, ice, fish, baits, etc., and
 which are watertight towards the interior of the boat, and
 whose closing appliances do not fulfil all the requirements of 5.3,
are not regarded as part of the cockpit and are not required to comply with clause 9. They shall be considered full
of water when assessing the fully loaded condition.
If fulfilling the requirements of 5.3 and clause 9, these lockers need not be considered full of water, but only filled
with the maximum loading corresponding to the “fully loaded” condition.
7 Requirements for drainage of quick-draining cockpits
7.1 Cockpit drainage
7.1.1 General
Draining shall only be by gravity.
7.1.2 When the boat is upright
When the boat is upright, at least 98 % of the cockpit volume shall drain, excluding any recess in accordance with
the exceptions of 6.2.
7.1.3 When the boat is heeled
The requirements in 7.1.3.1 and 7.1.3.2 shall be fulfilled when the boat is heeled to both port and starboard.
8 © ISO 2001 – All rights reserved

ISO 11812:2001(E)
7.1.3.1 Sailing monohulls
On sailing monohulls, drainage shall be provided for at least 90 % of V at the lesser heel angle of
C
 30° heel, or
 when the deck at side begins to touch the water.
7.1.3.2 Non-sailing boats and multihulls
On non-sailing boats and multihulls, drainage shall be provided for at least 90 % of V at 10° heel.
C
7.2 Draining time
The draining time is the time needed to drain the cockpit from the full height of water, h , down to a remainder of
C
0,1 m above cockpit bottom.
The draining time shall be measured or calculated with every appliance closed.
NOTE It is considered that a large cockpit volume relative to the boat's reserve buoyancy requires a correspondingly small
draining time, as a prolonged time with the cockpit full of water would expose the boat to great hazard.
If the draining section, expressed in square metres, is greater than or equal to 0,05 V , it is considered large
C
enough to fulfil the requirements and does not require a draining time assessment.
For other drain configurations, the draining time shall be assessed, and shall not be greater than t given by the
max
formulae in Table 3 or by the curves in Figure 2.
Table 3 — Maximum acceptable draining time, t
max
Time in minutes
Design category t
max
A 0,3/k but not greater than 5
C
B 0,45/k but not greater than 5
C
C 0,6/k but not greater than 5
C
D 0,9/k but not greater than 5
C
The cockpit volume, V , shall be measured from the cockpit bottom up to the top of h , with the eventual exception
C C
of 6.2, assuming that all closing appliances and drains are closed.
ISO 11812:2001(E)
Figure 2 — Maximum acceptable draining time t according to k and design category

max C
7.3 Number of drains
A quick-draining cockpit shall have at least two drains, one port and one starboard, unless one opening enables
drainage when the boat is heeled to both port and starboard, as required in 7.1.
7.4 Minimum drain dimensions
7.4.1 Internal dimensions of the drain
Drains with a circular cross section shall have a diameter of at least 25 mm. Drains with other cross-sectional
shapes shall have a cross-sectional area of at least 500 mm and a minimum dimension of 20 mm.
NOTE The purpose of this subclause is to avoid taking into account drains that could be easily clogged by loose objects or
ropes.
7.4.2 Eventual protective grids
If the drains are equipped with systems preventing loose objects from falling into the draining system, one shall be
aware that a grid of small holes is more prone to be clogged than the drain itself.
If the minimum passage dimension inside any part of these devices has at least a section of 125 mm (or a
diameter of 12 mm), and the total entry cross-section is at least 1,5 times the cross-section of the drain, Table 4
may be used for calculation of the draining time.
If the above conditions are not met, the head losses from the protection grid shall be considered. See normative
annex D.
7.5 Centreboard housings and other types of drain
Centreboard housings and other types of aperture may be used as drains if they are designed for this purpose.
10 © ISO 2001 – All rights reserved

ISO 11812:2001(E)
7.6 Drain fitting
The drain outlet running through the hull shall either be located above the waterline or, if below the waterline, be
fitted with seacocks (see 7.7), unless the drain outlet is an integral part of the hull extending from the outlet up to at
least 0,75 H above the waterline.

B,min
Figure 3 shows a drain outlet integral with the hull.

Key
1 Waterline
2 Top of integral penetration above 0,75 H : no seacock required
B,min
3 In this area, the drain is integral with the hull shell
Figure 3 — Drain outlet as an integral part of the hull
7.7 Drain piping design and construction
The scantling and design of drains shall take into account all the loads to which they may be subjected.
Drain piping shall be protected against damage from loose objects stowed in the boat and against being kicked or
stepped on.
Drain piping shall not trap water and shall only be used for cockpit drainage. This requirement does not apply to
drains fitted in centreboard housing or outboard wells and trunks.
Seacocks, through-hull fittings, and associated components shall comply with the requirements of ISO 9093-1 or
ISO 9093-2.
7.8 Draining time assessment
7.8.1 General
The draining time shall be determined either by measurement of the actual draining time, or by calculation.
7.8.2 Measurement of the draining time
The boat shall be placed near the fully loaded displacement and corresponding design trim.
ISO 11812:2001(E)
The cockpit is filled with water up to h , and the draining time to empty the cockpit between h and 0,1 m of water
C C
remaining in the cockpit is measured. This latter height shall be measured above the centre of the bottom surface
of the cokpit.
NOTE It may be useful to indicate the point located 0,1 m above the centre of the cockpit bottom with a tape mark.
7.8.3 Calculation of the draining time
A quick and approximate method of calculating the draining time calculation is given in 7.8.4. Simplifications in this
method may lead to small differences between measured and calculated draining time, but both methods are
considered valid.
More thorough methods of calculation are specified in annex C.
If the arrangement of cockpit and drains does not correspond to the cases of 7.8.4 or the methods of annex C, the
calculation method used shall be based on a practical test on a similar arrangement.
7.8.4 Quick method of calculation for cockpit fitted with two drains
7.8.4.1 Step 1: Determination of the required maximum draining time t
max
Determine t using k = V /(L B F ), i.e. the cockpit volume coefficient in accordance with 7.2.
max C C H max mean
7.8.4.2 Step 2: Determination of the reference draining time, t
ref
Calculate t = t /V which is the reference draining time (without head loss) for a set of two drains.
ref max C
7.8.4.3 Step 3: Determine whether the drain outlet is above or below the waterline
Determine whether the drain outlet is above or below the waterline when the cockpit is full. If the drain outlet is
above the waterline when the cockpit is empty and below it when the cockpit is full, one shall either conservatively
consider that the drain is always below the waterline, or make the calculation in both cases and calculate the final
time by interpolation.
Figure 4 shows some drain arrangements, but other arrangements may be used.

a) Cockpit bottom above the waterline b) Cockpit bottom below the waterline
12 © ISO 2001 – All rights reserved

ISO 11812:2001(E)
c) Drain above or below the waterline
Key
1 Waterline 4 Discharge above the waterline
2 Level of water overflow 5 Discharge below the waterline
3 Height above the waterline
Figure 4 — Examples of some drain arrangements
NOTE 1 According to 6.1, the cockpit bottom may be above the waterline when the cockpit is empty and below it with a full
cockpit.
In Figure 4c) an attempt shall not be made to apply the Bernouilli equation between water level in the cockpit and
point q (drain outlet) instead of point p (drain inlet). A bigger water flow would then occur but, as water is
uncompressible, the flow in the drain must be the same in p and q. The flow speed at the inlet therefore governs
the flow speed in the whole drain.
7.8.4.4 Step 4: Determination of the required drain diameter
Table 4 gives the approximate draining time for six cases: drain above or below the waterline, no elbow or two
elbows, and freeing port with and without a flap.
Enter the line corresponding approximately to the cockpit configuration and choose the drain diameter giving a
draining time t corresponding to the requirements. Interpolations may be used.
ref
Table 4 — Drain diameter as a function of t and typical drain arrangement

ref
Typical drain arrangement Values of t (min)
ref
Drain outlet above W , no elbow
8,8 5,8 4,1 3,0 2,3 1,8 1,5 1,2 1,0 0,9 0,8 0,7 0,5 0,4 0,3 0,3 0,2 0,2 0,2
L
Drain outlet above W , two elbows 10,0 6,7 4,7 3,5 2,7 2,2 1,8 1,5 1,3 1,1 0,9 0,8 0,6 0,5 0,4 0,4 0,3 0,3 0,2
L
Drain outlet below W , no elbow
10,8 7,2 5,1 3,9 3,0 2,4 2,0 1,6 1,4 1,2 1,0 0,9 0,7 0,6 0,5 0,4 0,3 0,3 0,2
L
Drain outlet below W , two elbows 11,8 7,9 5,7 4,3 3,3 2,7 2,2 1,8 1,5 1,3 1,2 1,0 0,8 0,6 0,5 0,4 0,4 0,3 0,3
L
Freeing port above W , no flap
10,1 7,0 5,2 3,9 3,1 2,5 2,1 1,8 1,5 1,3 1,1 1,0 0,8 0,6 0,5 0,4 0,4 0,3 0,3
L
Freeing port above W , with flap 15,2 10,5 7,7 5,9 4,7 3,8 3,1 2,6 2,2 1,9 1,7 1,5 1,2 0,9 0,8 0,7 0,6 0,5 0,4
L
Drain diameter d (mm) two drains 25 30 35 40 45 50 55 60 65 70 75 80 90 100 110 120 130 140 150

NOTE The time calculations given in Table 4 are for a draining time between a height of water h = 0,40 m to a remaining

C
0,10 m of water, with two drains, each one 1,2 m long and a coefficient of head loss at the entry K = 0,06 (see D.3). For different
values of h , the draining time is smaller (multiplied by coefficient C of Table C.1). The draining time for a freeing port fitted wit
...