Small craft - Hull construction and scantlings - Part 9: Sailing craft appendages (ISO 12215-9:2012)

This part of ISO 12215 defines the loads and specifies the scantlings of sailing craft appendages on monohull
sailing craft with a length of hull, LH, of up to 24 m, measured according to ISO 8666. It gives
 design stresses,
 the structural components to be assessed,
 load cases and design loads for keel, centreboard and their attachments,
 computational methods and modelling guidance, and
 the means for compliance with its provisions.

Kleine Wasserfahrzeuge - Rumpfbauweise und Dimensionierung - Teil 9: Anhänge von Segelbooten (ISO 12215-9:2012)

Petits navires - Construction de coques et échantillonnage - Partie 9: Appendices des bateaux à voiles (ISO 12215-9:2012)

Mala plovila - Konstrukcija trupa in zahtevane lastnosti - 9. del: Dodatni pribor jadrnic (ISO 12215-9:2012)

Ta del standarda ISO 12215 določa obremenitve in dimenzioniranje dodatnega pribora jadrnic na jadrnicah z enim trupom, pri čemer dolžina trupa (LH), merjena v skladu s standardom ISO 8666, ne presega 24 m. Podaja:
– konstrukcijske napetosti;
– sestavne dele konstrukcije, ki jih je treba oceniti;
– primere obremenitve in konstrukcijske obremenitve za gredelj, premični gredelj ter njune priključke;
– računalniške metode in navodila za modeliranje;
– načine skladnosti z določbami standarda.

General Information

Status
Published
Public Enquiry End Date
14-Mar-2018
Publication Date
15-Oct-2018
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
11-Oct-2018
Due Date
16-Dec-2018
Completion Date
16-Oct-2018

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Standards Content (sample)

SLOVENSKI STANDARD
SIST EN ISO 12215-9:2018
01-december-2018
1DGRPHãþD
SIST EN ISO 12215-9:2012

Mala plovila - Konstrukcija trupa in zahtevane lastnosti - 9. del: Dodatni pribor

jadrnic (ISO 12215-9:2012)

Small craft - Hull construction and scantlings - Part 9: Sailing craft appendages (ISO

12215-9:2012)
Kleine Wasserfahrzeuge - Rumpfbauweise und Dimensionierung - Teil 9: Anhänge von
Segelbooten (ISO 12215-9:2012)

Petits navires - Construction de coques et échantillonnage - Partie 9: Appendices des

bateaux à voiles (ISO 12215-9:2012)
Ta slovenski standard je istoveten z: EN ISO 12215-9:2018
ICS:
47.020.10 Ladijski trupi in njihovi Hulls and their structure
konstrukcijski elementi elements
47.080 ýROQL Small craft
SIST EN ISO 12215-9:2018 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 12215-9:2018
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SIST EN ISO 12215-9:2018
EN ISO 12215-9
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2018
EUROPÄISCHE NORM
ICS 47.080 Supersedes EN ISO 12215-9:2012
English Version
Small craft - Hull construction and scantlings - Part 9:
Sailing craft appendages (ISO 12215-9:2012)

Petits navires - Construction de coques et Kleine Wasserfahrzeuge - Rumpfbauweise und

échantillonnage - Partie 9: Appendices des bateaux à Dimensionierung - Teil 9: Anhänge von Segelbooten

voiles (ISO 12215-9:2012) (ISO 12215-9:2012)
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 12215-9:2018 E

worldwide for CEN national Members.
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SIST EN ISO 12215-9:2018
EN ISO 12215-9:2018 (E)
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

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SIST EN ISO 12215-9:2018
EN ISO 12215-9:2018 (E)
European foreword

The text of ISO 12215-9:2012 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 12215-9:2018.

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 April 2019, and conflicting national standards shall be

withdrawn at the latest by April 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 12215-9:2012.

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 12215-9:2012 has been approved by CEN as EN ISO 12215-9:2018 without any

modification.
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SIST EN ISO 12215-9:2018
EN ISO 12215-9:2018 (E)
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, 2.5 – 7.7.1, D.3.4, F.2.4.2 These clauses specify warnings and information to be

Owner’s manual included in the owner’s manual, if relevant.

Annex I, Part A, 3.1 - All clauses This part of ISO 12215 provides requirements for the

Structure strength of monohull sailing boat appendages with
conventional keel configurations. It deals with the design
stresses and structural efficiency of the keel and its
connections.
The load cases correspond to those for most
conventional keel configurations; however they may not
be appropriate in all cases and designers or builders still
need to ensure the suitability of their designs.
Scantlings derived from this standard are primarily
intended to apply to recreational sailing craft.
Dimensioning is regarded as reflecting current practice
provided the craft is correctly handled and operated at
speeds appropriate to the prevailing sea state.

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.
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SIST EN ISO 12215-9:2018
INTERNATIONAL ISO
STANDARD 12215-9
First edition
2012-06-15
Small craft — Hull construction and
scantlings —
Part 9:
Sailing craft appendages
Petits navires — Construction de la coque et échantillonnage —
Partie 9: Appendices des bateaux à voiles
Reference number
ISO 12215-9:2012(E)
ISO 2012
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SIST EN ISO 12215-9:2018
ISO 12215-9:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST EN ISO 12215-9:2018
ISO 12215-9:2012(E)
Contents Page

Foreword ............................................................................................................................................................ iv

Introduction ......................................................................................................................................................... v

1  Scope ...................................................................................................................................................... 1

2  Normative references ............................................................................................................................ 1

3  Terms and definitions ........................................................................................................................... 2

4  Symbols .................................................................................................................................................. 3

5  Design stresses ..................................................................................................................................... 4

6  Structural components to be assessed .............................................................................................. 6

7  Load cases ............................................................................................................................................. 6

7.1  General ................................................................................................................................................... 6

7.2  Load case 1 — Fixed keel at 90° knockdown ..................................................................................... 7

7.3  Load case 2 — Canted keel steady load at 30° heel with dynamic overload factor ....................... 8

7.4  Load case 3 — Keelboat vertical pounding ........................................................................................ 9

7.5  Load case 4 — Keelboat longitudinal impact ................................................................................... 10

7.6  Load case 5 — Centreboard on capsize recoverable dinghies ...................................................... 11

7.7  Load case 6 — Centreboard or dagger board upwind .................................................................... 11

7.8  Other load cases .................................................................................................................................. 12

8  Computational methods ..................................................................................................................... 15

8.1  General ................................................................................................................................................. 15

8.2  General guidance for assessment by 3D numerical procedures ................................................... 15

8.3  Assessment by strength of materials/non-computational-based methods .................................. 16

9  Compliance .......................................................................................................................................... 16

Annex A (normative) Application declaration ................................................................................................ 18

Annex B (informative) Information on metal for appendages and fasteners and

“established practice” for fastening and welding ........................................................................... 19

Annex C (informative) “Established practice” structural arrangement for ballast keels ......................... 30

Annex D (informative) “Established practice” calculation of keel fin strength (fixed or canting)

and fixed ballast keel connected by bolts ........................................................................................ 44

Annex E (informative) Geometrical properties of some typical appendage foil shapes ........................... 61

Annex F (informative) Simplified fatigue strength assessment ................................................................... 64

Bibliography ...................................................................................................................................................... 76

© ISO 2012 – All rights reserved iii
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SIST EN ISO 12215-9:2018
ISO 12215-9:2012(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 2.

The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 12215-9 was prepared by Technical Committee ISO/TC 188, Small craft.

ISO 12215 consists of the following parts, under the general title Small craft — Hull construction and

scantlings:

 Part 1: Materials: Thermosetting resins, glass-fibre reinforcement, reference laminate

 Part 2: Materials: Core materials for sandwich construction, embedded materials

 Part 3: Materials: Steel, aluminium alloys, wood, other materials
 Part 4: Workshop and manufacturing

 Part 5: Design pressures for monohulls, design stresses, scantlings determination

 Part 6: Structural arrangements and details
 Part 7: Scantling determination of multihulls
 Part 8: Rudders
 Part 9: Sailing craft appendages
iv © ISO 2012 – All rights reserved
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SIST EN ISO 12215-9:2018
ISO 12215-9:2012(E)
Introduction

The reason underlying the preparation of this part of ISO 12215 is that standards and recommended practices

for loads on the hull and the dimensioning of small craft differ considerably, thus limiting the general worldwide

acceptability of craft.

The loss of a keel leading to craft capsize is one of the major casualty hazards on sailing craft and therefore

the structural efficiency of all elements of the keel and its connection to the craft is paramount.

This part of ISO 12215 specifies the design loads and their associated stress factors. The user then has a

choice between one or the other of the following available options for assessing the structural arrangement.

a) Use of advanced engineering methods which allow the structure to be modelled as three-dimensional:

suitable methods include finite element analysis and subsets thereof such as matrix displacement or

framework methods. General guidance is provided on modelling assumptions within this part of

ISO 12215.

b) Use of simplified, generally two-dimensional, “strength of materials”-based stress equations: These are

presented in Annexes B to F and, if this option is chosen, use of the equations will be necessary to fulfil

the requirements of this part of ISO 12215.

This part of ISO 12215 has been developed applying present practice and sound engineering principles. The

design loads and criteria of this part of ISO 12215 may be used with the scantling determination equations of

this part of ISO 12215 or using equivalent engineering methods as indicated in a), above.

The dimensioning according to this part of ISO 12215 is regarded as reflecting current practice, provided the

craft is correctly handled in the sense of good seamanship and equipped and operated at a speed appropriate

to the prevailing sea state.

During the latter stages of the development of the ISO 12215 series, and after publication of key parts, a

number of authorities adopted this International Standard for the assessment of high-performance racing

yachts. While, in theory, a category A blue-water cruising yacht could experience the same loads as a

competitive racing yacht, the latter has not been the principal focus of ISO 12215. Consequently, designers

are strongly cautioned against attempting to design high-performance racing craft such that nearly all

structural components only just comply.
© ISO 2012 – All rights reserved v
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SIST EN ISO 12215-9:2018
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SIST EN ISO 12215-9:2018
INTERNATIONAL STANDARD ISO 12215-9:2012(E)
Small craft — Hull construction and scantlings —
Part 9:
Sailing craft appendages
1 Scope

This part of ISO 12215 defines the loads and specifies the scantlings of sailing craft appendages on monohull

sailing craft with a length of hull, L , of up to 24 m, measured according to ISO 8666. It gives

 design stresses,
 the structural components to be assessed,
 load cases and design loads for keel, centreboard and their attachments,
 computational methods and modelling guidance, and
 the means for compliance with its provisions.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.

ISO 898-1, Mechanical properties of fasteners made of carbon steel and alloy steel — Part 1: Bolts, screws

and studs with specified property classes — Coarse thread and fine pitch thread

ISO 3506-1, Mechanical properties of corrosion-resistant stainless steel fasteners — Part 1: Bolts, screws and

studs
ISO 8666, Small craft — Principal data

ISO 12215-3, Small craft — Hull construction and scantlings — Part 3: Materials — Steel, aluminium alloys,

wood, other materials

ISO 12215-5:2008, Small craft — Hull construction and scantlings — Part 5: Design pressures for monohulls,

design stress, scantlings determination

ISO 12215-6:2008, Small craft — Hull construction and scantlings — Part 6: Structural arrangements and

details

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
© ISO 2012 – All rights reserved 1
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SIST EN ISO 12215-9:2018
ISO 12215-9:2012(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
design category

sea and wind conditions for which a craft is assessed to be suitable, provided the craft is correctly handled in

the sense of good seamanship and operated at a speed appropriate to the prevailing sea state

3.1.1
design category A
“ocean category”

category of craft considered suitable to operate in seas with significant wave heights above 4 m and wind

speeds in excess of Beaufort Force 8, but excluding abnormal conditions such as hurricanes

3.1.2
design category B
“offshore category”

category of craft considered suitable to operate in seas with significant wave heights up to 4 m and winds of

Beaufort Force 8 or less
3.1.3
design category C
“inshore category”

category of craft considered suitable to operate in seas with significant wave heights up to 2 m and a typical

steady wind force of Beaufort Force 6 or less
3.1.4
design category D
“sheltered waters category”

category of craft considered suitable to operate in waters with significant wave heights up to and including

0,3 m with occasional waves of 0,5 m height, for example from passing vessels, and a typical steady wind

force of Beaufort 4 or less
3.2
loaded displacement mass
LDC

mass of the craft, including all appendages, when in the fully loaded ready-for-use condition as defined in

ISO 8666

NOTE 1 The displacement includes all possible options (generator, air conditioning, etc.).

NOTE 2 The loaded displacement mass is expressed in kilograms.
3.3
sailing craft
2/3

craft for which the primary means of propulsion is wind power, having A  0,07(m ) where A is the total

S LDC S

profile area of all sails that may be set at one time when sailing closed hauled, as defined in ISO 8666 and

expressed in square metres
NOTE 1 For the headsails, A considers the area of the fore triangle.
NOTE 2 The area of the wing-mast(s) is included in A .
3.4
mass of keel
KEEL

mass of the ballast keel, i.e. keel fin plus bulb, where fitted, and, for twin or multiple keels, of a single keel

NOTE The mass of keel is expressed in kilograms.
2 © ISO 2012 – All rights reserved
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SIST EN ISO 12215-9:2018
ISO 12215-9:2012(E)
4 Symbols

For the purposes of this document, unless specifically otherwise defined, the symbols given in Table 1 apply.

Table 1 — Symbols, coefficients, parameters in the main core of ISO 12215-9
(Sub)clause/table
Symbol Unit Designation/meaning of symbol
concerned
m Area of fully deployed centreboard 7.7.1
Reference sail area (mainsail + fore triangle + wing mast) as per
m 7.7.1
ISO 12217-2
Distance along keel centreline, from centre of gravity (CG) of keel to keel
a m 7
junction with hull or tuck
c m Distance along keel centreline from keel junction to floor mid-height 7
m Average value of c for several floors 7.5
m Proportion of the total side force taken by the centreboard 7.7.1
N Design force with i according to load case 7
2 2
g m/s Acceleration of gravity = 9,81 m/s 7
h Height of centre of area of A
m 7.7.1
CE S
m Height of keel between its bottom and hull connection 7.5.2
h Height of application of force F (load case 4)
m 7.5.2
k 1 Design category coefficient 5, Table 2
1 Load case coefficient 5, Table 3
1 Length displacement coefficient 7.7.1
1 Material coefficient 5, Table 2
MAT
L m Length of waterline in m conditions 7.5.2, 7.7.1
WL LDC
kg See definition 3.2 3.2, 7
LDC
kg See definition 3.4 3.4, 7.4
KEEL
Nm Design bending moment, with index I and J according to load case 7
st N/mm 5
Stress, which can be  or  , and where i can be LIM, d, u, y, yw or yu
 deg. Angle of attack of centreboard foil 7.7
% Elongation at break Table 2
 deg. Angle between keel axis and centreline for canting keels 7.3
© ISO 2012 – All rights reserved 3
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SIST EN ISO 12215-9:2018
ISO 12215-9:2012(E)
5 Design stresses

The maximum stress shall be calculated for each relevant structural component and load case.

The design stress, st , is the relevant limit stress multiplied by various stress coefficients:

stst k kk N/mm (1)
dLIM MAT LC DC
where

st is the limit stress, with st representing either , in direct stress, orin shear stress, and index

LIM
LIM is as follows:

 for metal in unwelded state or well clear of HAZ, min sts;0,5t , where index y is the

 
y u

yield strength and index u is the ultimate strength, i.e.  , for direct stress,  , for

yu yu
shear stress and  , for bearing stress;
by bu

 for metal within HAZ, min st ;0,5 st , where index y is the yield strength and index u

 
yw uw

is the ultimate strength, i.e.  ,, for direct stress,  , for shear stress and for

yw uw yw uw
, bearing stress;
byw buw

 for wood and fibre-reinforced polymer (FRP), the ultimate strength in tensile  ,

compressive  , flexural  , bearing,  or shear stress  ;
cu fu bu u

k is the material coefficient as defined in Table 2, with the design stress adjusted according to the

MAT
material;

k is the load case coefficient as defined in Table 3, with the design stress adjusted according to

the load case;

k is the design category coefficient as defined in Table 2, with allowance for an increase in design

stress for lower design categories due to less severe dynamic loadings than in higher design

categories.
Table 2 gives details on these variables.

The values of st — i.e. ,, for unwelded metals,  ,,, for welded metals in a

LIM yu u yw uw yw uw

heat-affected zone (HAZ), or  ,  ,  ,  or  for wood and FRP — shall be taken

tu cu fu bu u

 in accordance with ISO 12215-5:2008, i.e. according to tests or default values specified in its Annex C for

FRP, its Annex D for sandwich core, and its Annex E for laminated wood and plywood,

 in accordance with Annex B for the listed metals, including, where relevant, ISO 3506-1 for stainless steel

fasteners and ISO 898-1 for carbon steel or alloy steel fasteners, and

 for other metals, either from a recognized standard or from tests made in accordance with the relevant

International Standard.
4 © ISO 2012 – All rights reserved
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SIST EN ISO 12215-9:2018
ISO 12215-9:2012(E)
Table 2 — Design stresses and stress coefficients
Variable Material/designation Value
b,c
min. sts;0,5t
Metals, unwelded or well clear of HAZ 
a b,c
st min. st ;0,5 st
Metals, within HAZ, in welded condition
LIM yw uw
 ,, , and as relevant
Wood or FRP as dictated by sense of applied stress
uc ut uf ub u
Stress factor
Metals with elongation at break,  % ≥ 7
0,75
MAT
Metals with elongation at break,  % <7 min.(0,0625 + 0,3125;0,75)
R R
Wood and FRP 0,33
Stress factor (see Table 3)
Stress factor
Craft of design categories A and B 1,00
Craft of design categories C and D 1,25

Generally, the heat-affected zone is considered as being 50 mm from the weld (see also the Note in F.3.4.3).

For metals, 0,58  .

Bearing stress depends on material type (Ref [8] gives   = 2,8 for Glass CSM and 0,91 for roving), metal regulation usually

ub uc

gives 2,4 to 3 for bolts (but with restrictions: far from edges, min. bolt spacing, min. thickness/bolt d). Values derived from tests are

recommended.

The factor gives 0,75 for  ≥ 7%, and 0,375 for  =1% and linear interpolation in between. Values of  are given in Table B.2.

R R R
Table 3 — Value of k stress factor according to load case
Value of
Load
Keels and appendages — Load case description Subclause
case
Keel bolt 7.2 0,67
1 Other elements of fixed keel — metal — 0,8
Other elements of fixed keel — FRP — 0,9
Canting keel — metal 7.3 0,8
Canting keel — FRP — 0,9
3 Keel vertical pounding 7.4 1
4 Keelboat longitudinal impact 7.5 1
5 Dinghy capsize recovery (strength of centre/dagger board) 7.6 1,34
6 Centre/dagger board upwind 7.7 1,0

Load case 1 treats bolts differently from other structural materials components. The design stress of bolts is lower than that of other

structural components so as to recognize stress concentration effects in bolts and accord with long-standing design practice.

The requirements of this part of ISO 12215 are strength-criteria based. In some cases, such as keel fins constructed of lower

modulus materials, the need to limit deflections and/or increase natural frequencies may require a substantial increase in scantlings

above those requirements. Such cases are outside the scope of this part of ISO 12215.

© ISO 2012 – All rights reserved 5
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SIST EN ISO 12215-9:2018
ISO 12215-9:2012(E)
6 Structural components to be assessed

CAUTION — Keel loss has been found on several occasions to be attributable to insufficient thickness

of bottom plating in respect of the keel, in particularly, connecting bolts or inadequate load paths

between connecting bolts and the corresponding structure, including bolts located too far from the

relevant stiffener. It is strongly recommended that the provisions of D.5 and Table D.2 be followed and,

in particular, for bolts located too far from a stiffener, those of Table D.2, item 3.

The following shall be considered when assessing or designing the structure covered by this part of

ISO 12215.

 Keel-to-hull connection (bolts, wedge connection, stub keel, etc.) — see Figures 1, C.3, C.4 and D.1.

 Bottom shell plating in respect of the keel bolts and transition arrangements beyond the keel bolt zone

into the hull structure: in the case of bolted keels on a hull bottom of sandwich construction, the general

practice outlined in Annex D is to h
...

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