Small craft - Hull construction and scantlings - Part 8: Rudders (ISO 12215-8:2009, including Cor 1:2010)

This part of ISO 12215 gives requirements on the scantlings of rudders fitted to small craft with a length of hull,
LH, of up to 24 m, measured according to ISO 8666. It applies only to monohulls.
This part of ISO 12215 does not give requirements on rudder characteristics required for proper steering
capabilities.
This part of ISO 12215 only considers pressure loads on the rudder due to craft manoeuvring. Loads on the
rudder or its skeg, where fitted, induced by grounding or docking, where relevant, are out of scope and need
to be considered separately.
NOTE Scantlings derived from this part of ISO 12215 are primarily intended to apply to recreational craft including
charter craft.

Kleine Wasserfahrzeuge - Rumpfbauweise und Dimensionierung - Teil 8: Ruder (ISO 12215-8:2009, einschließlich Cor 1:2010)

Dieser Teil von ISO 12215 legt die Bestimmungen für die Dimensionierung von Rudern, die an kleinen Wasserfahrzeugen mit einer Rumpflänge (LH) bis 24 m, gemessen nach ISO 8666, befestigt sind, fest. Dieser Teil von ISO 12215 gilt nur für Einrumpf-Wasserfahrzeuge.
Dieser Teil der ISO 12215 enthält keine Anforderungen für Rudereigenschaften zur ordnungsgemäßen Steuerung.
Dieser Teil der ISO 12215 berücksichtigt nur Drucklasten auf das Ruder, die durch das Manövrieren des Fahrzeugs entstehen. Lasten auf dem Ruder oder dem Steg, wo vorhanden, hervorgerufen durch Grundberührung oder Andocken, wo zutreffend, sind außerhalb des Anwendungsbereichs und müssen separat berücksichtigt werden.
ANMERKUNG Dimensionierungen, die sich aus diesem Teil von ISO 12215 ergeben, sind in erster Linie für Freizeit-wasserfahrzeuge einschließlich Charterbooten vorgesehen.

Petits navires - Construction de coques et échantillonnage - Partie 8: Gouvernails (ISO 12215-8:2009; y compris Cor 1:2010)

Mala plovila - Konstrukcija trupa in zahtevane lastnosti - 8. del: Krmila (ISO 12215-8:2009, vključuje popravek Cor 1:2010)

Ta del standarda ISO 12215 podaja zahteve glede zahtevanih lastnosti krmil, ki so nameščena na mala plovila z dolžino trupa (LH) do 24 m, izmerjeno v skladu s standardom ISO 8666. Uporablja se samo za plovila z enim trupom.
Ta del standarda ISO 12215 ne podaja zahteve glede lastnosti krmil, zahtevanih za zagotavljanje ustreznih zmožnosti
krmarjenja.
Ta del standarda ISO 12215 obravnava samo tlačne obremenitve na krmilo zaradi krmarjenja plovila. Obremenitve na krmilo ali njegovo gred (če je nameščena) zaradi pristajanja (kjer je to ustrezno) ne spadajo na področje uporabe in jih je treba obravnavati ločeno.
OPOMBA: Zahtevane lastnosti iz tega dela standarda ISO 12215 so namenjene predvsem za plovila za rekreacijo, vključno s čarterskimi plovili.

General Information

Status
Published
Publication Date
02-Oct-2018
Technical Committee
Drafting Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
03-Oct-2018
Completion Date
03-Oct-2018

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SLOVENSKI STANDARD
SIST EN ISO 12215-8:2018
01-december-2018
1DGRPHãþD
SIST EN ISO 12215-8:2009
SIST EN ISO 12215-8:2009/AC:2011

0DODSORYLOD.RQVWUXNFLMDWUXSDLQ]DKWHYDQHODVWQRVWLGHO.UPLOD ,62

YNOMXþXMHSRSUDYHN&RU

Small craft - Hull construction and scantlings - Part 8: Rudders (ISO 12215-8:2009,

including Cor 1:2010)
Kleine Wasserfahrzeuge - Rumpfbauweise und Dimensionierung - Teil 8: Ruder (ISO
12215-8:2009, einschließlich Cor 1:2010)

Petits navires - Construction de coques et échantillonnage - Partie 8: Gouvernails (ISO

12215-8:2009; y compris Cor 1:2010)
Ta slovenski standard je istoveten z: EN ISO 12215-8:2018
ICS:
47.020.10 Ladijski trupi in njihovi Hulls and their structure
konstrukcijski elementi elements
47.080 ýROQL Small craft
SIST EN ISO 12215-8:2018 en,fr,de

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

---------------------- Page: 1 ----------------------
SIST EN ISO 12215-8:2018
---------------------- Page: 2 ----------------------
SIST EN ISO 12215-8:2018
EN ISO 12215-8
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2018
EUROPÄISCHE NORM
ICS 47.080 Supersedes EN ISO 12215-8:2009
English Version
Small craft - Hull construction and scantlings - Part 8:
Rudders (ISO 12215-8:2009, including Cor 1:2010)

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

échantillonnage - Partie 8: Gouvernails (ISO 12215- Dimensionierung - Teil 8: Ruder (ISO 12215-8:2009,

8:2009; y compris Cor 1:2010) einschließlich Cor 1:2010)
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 12215-8:2018 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 12215-8:2018
EN ISO 12215-8:2018 (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

---------------------- Page: 4 ----------------------
SIST EN ISO 12215-8:2018
EN ISO 12215-8:2018 (E)
European foreword

The text of ISO 12215-8:2009, including Cor 1:2010 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 12215-8:2018.

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 12215-8:2009.

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 12215-8:2009, including Cor 1:2010 has been approved by CEN as EN ISO 12215-8:2018

without any modification.
---------------------- Page: 5 ----------------------
SIST EN ISO 12215-8:2018
EN ISO 12215-8:2018 (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 Requirements Clause(s)/sub- Remarks/Notes
of Directive 2013/53/EU clause(s) of
this EN

Annex I, Part A, 2.5 – 7.2, 7.3, 12.1 These clauses specify warnings and information to

Owner’s manual be included in the owner’s manual, if relevant.
Annex I, Part A, 3.1 - All clauses This part of this standard provides scantling
Structure requirements applicable to five types of rudder
configuration: Type I to Type V, as shown in Figures
2 and 3 of clause 6.2. It applies only to monohulls.
The application of this part of this standard does not
ensure proper steering capabilities.
Single bearing spade rudders and single hull bearing
skeg rudders are not addressed by this standard.
Annex I, Part A, 5.4.2 - 6.1.6 In respect of the ability of emergency tiller
Steering system – components to transmit rudder torque.
Emergency arrangements

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.
---------------------- Page: 6 ----------------------
SIST EN ISO 12215-8:2018
INTERNATIONAL ISO
STANDARD 12215-8
First edition
2009-05-15
Small craft — Hull construction and
scantlings —
Part 8:
Rudders
Petits navires — Construction de coques et échantillonnage —
Partie 8: Gouvernails
Reference number
ISO 12215-8:2009(E)
ISO 2009
---------------------- Page: 7 ----------------------
SIST EN ISO 12215-8:2018
ISO 12215-8:2009(E)
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Published in Switzerland
ii © ISO 2009 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 12215-8:2018
ISO 12215-8:2009(E)
Contents Page

Foreword............................................................................................................................................................. v

Introduction ....................................................................................................................................................... vi

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

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

3 Terms and definitions........................................................................................................................... 1

4 Symbols ................................................................................................................................................. 2

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

5.1 Rudder material..................................................................................................................................... 4

6 Rudder and steering arrangement, rudder types .............................................................................. 5

6.1 General................................................................................................................................................... 5

6.2 Rudder types ......................................................................................................................................... 6

7 Design rudder force calculation........................................................................................................ 10

7.1 General................................................................................................................................................. 10

7.2 Force F and corresponding load case ............................................................................................ 11

7.3 Force F and corresponding load case ............................................................................................ 12

8 Rudder bending moment and reactions at bearings ...................................................................... 13

8.1 General................................................................................................................................................. 13

8.2 Analysis of spade rudder (Type I)..................................................................................................... 13

8.3 Analysis of skeg rudders (Types II to V) .......................................................................................... 14

9 Rudder design torque, T .................................................................................................................... 16

10 Rudder and rudder stock design ...................................................................................................... 17

10.1 Load bearing parts of the rudder ...................................................................................................... 17

10.2 Metal rudder stock material ............................................................................................................... 17

10.3 Design stress for metal rudder stock ............................................................................................... 18

10.4 Required diameter for solid circular metal rudder stocks ............................................................. 18

10.5 Vertical variation of the diameter of a Type I rudder (spade)......................................................... 18

10.6 Round tubular stocks......................................................................................................................... 19

10.7 Non-circular metal rudder stocks ..................................................................................................... 20

10.8 Simple non-isotropic rudder stocks (e.g. wood or FRP).................................................................. 21

10.9 Complex structural rudders and rudder stocks in composite....................................................... 21

10.10 Check of deflection of Type I rudder stocks between bearings .................................................... 21

11 Equivalent diameter at the level of notches.....................................................................................22

12 Rudder bearings, pintles and gudgeons.......................................................................................... 22

12.1 Bearing arrangement.......................................................................................................................... 22

12.2 Clearance between stock and bearings ........................................................................................... 23

13 Rudder stock structure and rudder construction ........................................................................... 24

13.1 Rudder stock structure ...................................................................................................................... 24

13.2 Rudder construction........................................................................................................................... 24

13.3 FRP rudder blades.............................................................................................................................. 24

13.4 Non-FRP rudder blades...................................................................................................................... 25

14 Skeg structure..................................................................................................................................... 25

14.1 General................................................................................................................................................. 25

14.2 Design stress ...................................................................................................................................... 25

Annex A (normative) Metal for rudder stock ................................................................................................. 26

© ISO 2009 – All rights reserved iii
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SIST EN ISO 12215-8:2018
ISO 12215-8:2009(E)

Annex B (normative) Complex composite rudder stock design ................................................................. 30

Annex C (normative) Complete calculation for rudders with skeg ............................................................. 32

Annex D (informative) Geometrical properties of some typical rudder blade shapes .............................. 36

Annex E (informative) Vertical variation of diameter for Type I rudders .................................................... 39

Annex F (informative) Type I rudders — Deflection of stock between bearings ....................................... 41

Bibliography ..................................................................................................................................................... 44

iv © ISO 2009 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 12215-8:2018
ISO 12215-8:2009(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 12215-8 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 8: Rudders
© ISO 2009 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 12215-8:2018
ISO 12215-8:2009(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. This part of ISO 12215 has been set towards the lower boundary range of common

practice.

The objective of this part of ISO 12215 is to achieve an overall structural strength that ensures the watertight

and weathertight integrity of the craft.

The working group considers this part of ISO 12215 to have 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 such as

continuous beam theory, matrix-displacement method and classical lamination theory, as indicated within.

Considering future development in technology and craft types, and small craft presently outside the scope of

this part of ISO 12215, provided that methods supported by appropriate technology exist, consideration may

be given to their use as long as equivalent strength to this part of ISO 12215 is achieved.

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.
vi © ISO 2009 – All rights reserved
---------------------- Page: 12 ----------------------
SIST EN ISO 12215-8:2018
INTERNATIONAL STANDARD ISO 12215-8:2009(E)
Small craft — Hull construction and scantlings —
Part 8:
Rudders
1 Scope

This part of ISO 12215 gives requirements on the scantlings of rudders fitted to small craft with a length of hull,

L , of up to 24 m, measured according to ISO 8666. It applies only to monohulls.

This part of ISO 12215 does not give requirements on rudder characteristics required for proper steering

capabilities.

This part of ISO 12215 only considers pressure loads on the rudder due to craft manoeuvring. Loads on the

rudder or its skeg, where fitted, induced by grounding or docking, where relevant, are out of scope and need

to be considered separately.

NOTE Scantlings derived from this part of ISO 12215 are primarily intended to apply to recreational craft including

charter craft.
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 8666, Small craft — Principal data

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

design stresses, scantlings determination
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
design categories

sea and wind conditions for which a craft is assessed by this part of ISO 12215 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 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

© ISO 2009 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 12215-8:2018
ISO 12215-8:2009(E)
3.1.2
design category B (“offshore”)

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 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 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 Force 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
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 is the area of the fore triangle.

NOTE 2 In the rest of this part of ISO 12215, non-sailing craft are called motor craft.

4 Symbols

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

NOTE The symbols used in the annexes are not listed in Table 1.
2 © ISO 2009 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 12215-8:2018
ISO 12215-8:2009(E)
Table 1 — Symbols, coefficients, parameters
(Sub)clause/table
Symbol Unit Designation/meaning of symbol
concerned
A m Total area of the moving part of the rudder 6.2.1, 6.2.3
A m Rudder effective area (Types II to IV) 6.2.3
A m Rudder blade area (Types II to IV) or top blade area (Type V) 6.2.3
A m Bottom rudder blade area (Type V) 6.2.3
A m Rudder skeg area [only used to determine type (see Figure 3)] 6.2.3
c m Rudder chord length at centre of area level 6.2.1, 6.2.2
c m Length of the top chord (Type I) 6.2.1
c m Length of the bottom chord (Type I) 6.2.1

co m Compensation at top chord (distance from LE to rotation axis) (Type I) 6.2.2

co m Compensation at bottom chord (distance from LE to stock CL) (Type I) 6.2.2
d mm Required solid stock diameter 10.4
d mm Inner diameter of tubular stock 10.6
d mm Outer diameter of tubular stock 10.6
F N Final side force on rudder 7.1
F N Side force on rudder in design category sea state 7.2
F N Side force on rudder during a turn at speed in slight sea 7.3
h m Height between rudder top and centre of hull bearing 6.2.1
h m Height between rudder top and centre of area 6.2.1
h m Height between rudder top and centre of skeg bearing (Type V) 6.2.3
h m Height between rudder bottom and centre of skeg bearing (Type V) 6.2.3

h m Height between centre of upper bearing and a point inside the hull (Type I) 6.2.1

h m Height between bottom of spade and a point outside the hull (Type I) 6.2.1
h m Average height of rudder blade (see Figure 1) 6.2.1
h m Height of skeg from hull attachment to skeg bearing (Types II to V) 6.2.3
h m Height between centres of hull (lower) bearing and upper bearing 6.2.1
k 1 Rudder bending coefficient 6.2.1
k 1 Coefficient lowering force for flat or wedge rudder blade shape 7.3
FLAT
k 1 Coefficient lowering force due to gap hull/rudder top 7.2
GAP
k 1 Length displacement coefficient 7.2
k 1 Coefficient for skeg deflection 8.3.4

k 1 Coefficient considering extra load due to sea in design categories A and B 7.2

SEA
k 1 Coefficient considering lower required service in design categories C and
SERV
7.3
k 1 Coefficient lowering design stress for F 7.3
SIG 2
k 1 Coefficient considering lower usage of craft with damage survey 7.2
USE
k 1 Fibre type factor 13.3.1.2
L m Effective length of the skeg 8.3.4
© ISO 2009 – All rights reserved 3
---------------------- Page: 15 ----------------------
SIST EN ISO 12215-8:2018
ISO 12215-8:2009(E)
Table 1 (continued)
(Sub)clause/table
Symbol Unit Designation/meaning of symbol
concerned
L m Length at waterline, according to ISO 8666 in m conditions 7.2
WL LDC
M Nm Bending moments on the rudder stock or skeg 8
M , M Nm Bending moments at skeg or hull 8.3.4
S H
m kg Loaded displacement mass 3.2, 7.2
LDC
r m Horizontal distance from rudder force to stock axis 6.2.1
r m Minimum value of r 9
min

R , R , R N Reaction force at upper bearing, hull bearing, skeg bearing, respectively 8

U H S
t mm Skin thickness of tubular or hollowed closed section Table 6
T Nm Torque (twisting moment) on the rudder stock 9

u m Longitudinal distance from leading edge to stock axis at centroid chord 6.2.1

V knots Maximum speed of craft in calm water, m conditions 7.3
MAX LDC
w kg/m Minimum fibre mass per area of rudder blade 13.3.1.2
z m Effective bending moment lever z = k ⋅ h + h 8.2.1
b b b r c
z m Equivalent bending moment lever 10.4
α 1 Tip chord to root chord ratio (c /c) 6.2.2
2 1
Λ 1 Geometric aspect ratio of the rudder 6.2.1, 6.2.3
σ N/mm Direct stress (ultimate, yield, design) 5
τ N/mm Shear stress (ultimate, yield, design) 5
χ 1 Ratio between reaction at skeg and rudder force 8.3.2
5 Design stresses
5.1 Rudder material
Values of design stresses shall be taken from Table 2
Table 2 — Values of design stresses
Stresses in newtons per square millimetre
Direct stresses
Combined
Material
Tensile/compressive Shear Bearing
stresses
σ τ σ
d d db
min σ ; 0,5 σ 0,58 τ 1,8 σ
Metals yu σ + 3τσu
d d
Wood and fibre-reinforced ⎛⎞ ⎛ ⎞
0,5 × σ 0,5 τ 1,8 σ
+< 0,25
u u d ⎜⎟ ⎜ ⎟
plastics (FRP) ⎜⎟ ⎜ ⎟
⎝⎠uu⎝ ⎠

Steel, stainless steel, aluminium alloys, titanium alloys, copper alloys (see Annex A). In welded condition for welded metals.

4 © ISO 2009 – All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 12215-8:2018
ISO 12215-8:2009(E)
In Table 2,
⎯ σ is the design tensile, compressive, or flexural strength (as relevant);
⎯ σ is the ultimate tensile, compressive, or flexural strength (as relevant);
⎯ σ is the yield tensile, compressive, or flexural strength (as relevant);
⎯ σ is the design bearing strength;
⎯ τ is the design shear strength;
⎯ τ is the ultimate shear strength.
Additional requirements are given in Annex A (metals) and Annex B (composites)

For wood and composites, the strength values of the relevant annexes of ISO 12215-5 shall be used.

6 Rudder and steering arrangement, rudder types
6.1 General
6.1.1 General definition

The rudder and steering arrangement comprises all components necessary for manoeuvring the craft, from

the rudder and the rudder operating gear to the steering position.
Rudder and steering equipment shall be arranged so as to permit inspection.

NOTE It is good practice that the rudder keeps the steering effect after grounding (for exam

...

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