EN ISO 12215-5:2008

SLOVENSKI STANDARD
01-julij-2008
0DODSORYLOD.RQVWUXNFLMDWUXSDLQ]DKWHYDQHODVWQRVWLGHO1DþUWRYDQLWODNL]D
WUXSHQDþUWRYDQHQDSHWRVWLLQGRORþDQMHODVWQRVWL,62
Small craft - Hull construction and scantlings - Part 5: Design pressures for monohulls,
design stresses, scantlings determination (ISO 12215-5:2008)
Kleine Wasserfahrzeuge - Rumpfbauweise und Dimensionierung - Teil 5:
Entwurfsdrücke, Entwurfsspannungen und Ermittlung der Dimensionierung (ISO 12215-
5:2008)
Petits navires - Construction de la coque et échantillonnage - Partie 5: Pressions de
conception pour monocoques, contraintes de conception, détermination de
l'échantillonnage (ISO 12215-5:2008)
Ta slovenski standard je istoveten z: EN ISO 12215-5:2008
ICS:
47.020.10 Ladijski trupi in njihovi Hulls and their structure
konstrukcijski elementi elements
47.080 ýROQL Small craft
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 12215-5
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2008
ICS 47.020.10; 47.080
English Version
Small craft - Hull construction and scantlings - Part 5: Design
pressures for monohulls, design stresses, scantlings
determination (ISO 12215-5:2008)
Petits navires - Construction de la coque et échantillonnage Kleine Wasserfahrzeuge - Rumpfbauweise und
- Partie 5: Pressions de conception pour monocoques, Dimensionierung - Teil 5: Entwurfsdrücke für
contraintes de conception, détermination de Einrumpffahrzeuge, Entwurfsspannungen, Ermittlung der
l'échantillonnage (ISO 12215-5:2008) Dimensionierung (ISO 12215-5:2008)
This European Standard was approved by CEN on 28 December 2007.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12215-5:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3
Annex ZA (informative) Relationship between this International Standard and the Essential
Requirements of EU Directive 94/25/EC as amended by Directive 2003/44/EC .4

Foreword
This document (EN ISO 12215-5:2008) has been prepared by Technical Committee ISO/TC 188 "Small craft"
in collaboration with Technical Committee CEN/SS T01 “Shipbuilding and maritime structures” the secretariat
of which is held by CMC.
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 October 2008, and conflicting national standards shall be withdrawn at
the latest by October 2008.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
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 EC Directive(s).
For relationship with EC Directive, 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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 12215-5:2008 has been approved by CEN as a EN ISO 12215-5:2008 without any
modification.
Annex ZA
(informative)
Relationship between this International Standard and the Essential
Requirements of EU Directive 94/25/EC as amended by Directive
2003/44/EC
This International Standard has been prepared under a mandate given to CEN by the European Commission
to provide one means of conforming to Essential Requirements of the New Approach Directive 94/25/EC as
amended by Directive 2003/44/EC.

Once this standard is cited in the Official Journal of the European Communities under that Directive and has
been implemented as a national standard in at least one Member State, 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 International Standard and Directive 94/25/EC as
amended by Directive 2003/44/EC

Clause(s)/sub-clause(s) of Essential requirements (ERs) of EU Qualifying remarks/Notes
this International Standard Directive 94/25/EC as amended by
Directive 2003/44/EC
All clauses Annex I, Part A, Clause 3.1, Structure The standard provides requirements for scantling
determination for monohull craft constructed from
fibre reinforced plastics, aluminium or steel alloys,
glued wood (laminate) or similar suitable
materials.
WARNING — Other requirements and other EU Directives may be applicable to the products falling
within the scope of this standard.

INTERNATIONAL ISO
STANDARD 12215-5
First edition
2008-04-15
Small craft — Hull construction
and scantlings —
Part 5:
Design pressures for monohulls, design
stresses, scantlings determination
Petits navires — Construction de la coque et échantillonnage —
Partie 5: Pressions de conception pour monocoques, contraintes de
conception, détermination de l'échantillonnage

Reference number
ISO 12215-5:2008(E)
©
ISO 2008
ISO 12215-5:2008(E)
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ii © ISO 2008 – All rights reserved

ISO 12215-5:2008(E)
Contents Page
Foreword. v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Symbols . 4
5 General. 6
6 Dimensions, data and areas . 7
6.1 Dimensions and data. 7
6.2 Areas . 7
7 Pressure adjusting factors . 9
7.1 General. 9
7.2 Design category factor k . 9
DC
7.3 Dynamic load factor n . 9
CG
7.4 Longitudinal pressure distribution factor k . 10
L
7.5 Area pressure reduction factor k . 11
AR
7.6 Hull side pressure reduction factor k . 12
Z
7.7 Superstructure and deckhouse pressure reduction factor k . 13
SUP
7.8 Light and stable sailing craft pressure correcting factor for slamming k . 13
SLS
8 Design pressures. 14
8.1 Motor craft design pressure . 14
8.2 Sailing craft design pressure . 16
8.3 Watertight bulkheads and integral tank boundaries design pressure. 16
8.4 Design pressures for structural components where k would be u 0,25 . 18
AR
9 Dimensions of panels and stiffeners. 19
9.1 Dimensions of plating panels. 19
9.2 Dimensions of stiffeners. 23
10 Plating — Scantling equations . 25
10.1 Thickness adjustment factors for plating .25
10.2 FRP single-skin plating . 28
10.3 Metal plating — Aluminium alloy and steel. 29
10.4 Laminated wood or plywood single-skin plating . 30
10.5 FRP sandwich plating. 31
10.6 Single-skin plating minimum thickness .35
11 Stiffening members requirements . 36
11.1 General. 36
11.2 Properties adjustment factors for stiffeners.37
11.3 Design stresses for stiffeners . 37
11.4 Requirements for stiffeners made with similar materials. 38
11.5 Requirements for stiffeners made with dissimilar materials . 39
11.6 Effective plating . 40
11.7 Overall dimensions of stiffeners . 41
11.8 Structural bulkheads . 43
11.9 Structural support for sailing craft ballast keel.44
ISO 12215-5:2008(E)
12 Owner's manual. 44
12.1 General . 44
12.2 Normal mode of operation . 44
12.3 Possibility of outer skin damage. 44
Annex A (normative) Simplified method for scantling determination . 45
Annex B (normative) Drop test for boats of < 6 m. 49
Annex C (normative) FRP laminates properties and calculations . 52
Annex D (normative) Sandwich mechanical core properties and sandwich calculation. 63
Annex E (normative) Wood laminate properties and wood calculations . 69
Annex F (normative) Mechanical properties of metals. 78
Annex G (normative) Geometric properties of stiffeners. 80
Annex H (normative) Laminate stack analysis . 97
Bibliography . 108

iv © ISO 2008 – All rights reserved

ISO 12215-5:2008(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 12215-5 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 monuhulls, design stresses, scantlings determination
⎯ Part 6: Structural arrangements and details
⎯ Part 7: Scantling determination of multihulls
⎯ Part 8: Rudders
⎯ Part 9: Sailing boats — Appendages and rig attachment
ISO 12215-5:2008(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 from one to another, thus limiting
the general worldwide acceptability of boat scantlings. This part of ISO 12215 has been set towards the lower
boundary of the range of current 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. It is intended to be a tool to assess the scantlings of a craft against
lower bound practice and it is not intended to be a structural design procedure
The scantling requirements are based principally on providing adequate local strength. Serviceability issues
such as deflection under normal operating loads, global strength and its connected shell and deck stability are
not addressed. The criteria contained within may need to be supplemented by additional considerations
deemed necessary by the designer of the structure.
The mechanical property data supplied as default values make no explicit allowance for deterioration in
service nor provide any guarantee that these values can be obtained for any particular craft. The responsibility
for the decision to use this part of ISO 12215 as part of the design procedure rests solely with the designer
and/or manufacturer.
The design pressures given in this part of ISO 12215 are only used with the given equations.
Considering future development in technology and boat types and small craft currently outside the scope of
this part of ISO 12215, provided methods supported by appropriate technology exist, consideration may be
given to their use provided equivalent support for 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 operated at a speed appropriate to the
prevailing sea state.
Important notice:
1) ISO/TC 188/WG 18 believes that this part of ISO 12215 is the best that can be achieved at the time of
publication. It has therefore decided to publish this document as an ISO Standard. It is anticipated that
wider usage may reveal a number of issues that require modification. It is for this reason that WG 18
has asked for a revision of the document at the same time as its publication. This revision agreement
will enable the group to amend this part of ISO 12215 quickly should this prove necessary.
2) In furtherance of this, this part of ISO 12215 needs to be applied with a critical mind, and users are
invited to report to the TC secretariat, or national standardization body, any items that are considered to
require correction, together with supporting evidence, be that theoretical or based on satisfactory, long-
term service experience with actual boats operating in the appropriate design category sea states.

vi © ISO 2008 – All rights reserved

INTERNATIONAL STANDARD ISO 12215-5:2008(E)

Small craft — Hull construction and scantlings —
Part 5:
Design pressures for monohulls, design stresses, scantlings
determination
1 Scope
This part of ISO 12215 applies to the determination of design pressures and stresses, and to the
determination of the scantlings, including internal structural members of monohull small craft constructed from
fibre-reinforced plastics, aluminium or steel alloys, glued wood or other suitable boat building material, with a
length of hull, L , in accordance with ISO 8666, between 2,5 m and 24 m. It only applies to boats in the intact
H
condition.
It only applies to craft with a maximum speed u 50 knots in m conditions.
LDC
The assessment shall generally include all parts of the craft that are assumed watertight or weathertight when
assessing stability, freeboard and buoyancy in accordance with ISO 12217 and are essential to the safety of
the craft and of persons on board.
For the complete scantlings of the craft, this part of ISO 12215 is used in conjunction with Part 6, for details,
Part 7 for multihulls, Part 8 for rudders and Part 9 for appendages and rig attachment.
The scantling determination of windows, portlights, deadlights, hatches and doors, is in accordance with
ISO 12216. The structure supporting these elements is in accordance with this part of ISO 12215.
NOTE 1 Scantlings derived from this part of ISO 12215 are primarily intended to apply to recreational craft including
recreational charter vessels and may not be suitable for performance racing craft.
NOTE 2 This part of ISO 12215 is based on the assumption that scantlings are governed solely by local loads.
NOTE 3 The scantling requirements of this part of ISO 12215 are considered to correspond to the minimum strength
requirements of motor and sailing craft which are operated in a safe and responsible manner, having due cognisance of
the prevailing conditions.
Pressures and stresses are normally expressed in pascals, kilopascals or megapascals. For the purposes of a
better understanding for the users of this part of ISO 12215, the pressures are expressed in kilonewtons per
square metre (1kN/m = 1kPa) and stresses or elastic moduli are expressed in newtons per square millimetre
(1 N/mm = 1 MPa).
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 178, Plastics — Determination of flexural properties
ISO 527-1, Plastics — Determination of tensile properties — Part 1: General principles
ISO 12215-5:2008(E)
ISO 527-2, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and
extrusion plastics
ISO 844, Rigid cellular plastics — Determination of compression properties
ISO 845, Cellular plastics and rubbers — Determination of apparent density
ISO 1922, Rigid cellular plastics — Determination of shear strength
ISO 8666:2002, Small craft — Principal data
ISO 12215-3, Small craft — Hull construction and scantlings — Part 3: Materials: Steel, aluminium alloys,
wood, other materials
ISO 12215-6, Small craft — Hull construction and scantlings — Part 6: Structural arrangements and details
ISO 12215-7, Small craft — Hull construction and scantlings — Part 7: Scantling determination of multihulls
ISO 12215-9, Small craft — Hull construction and scantlings — Part 9: Sailing boats — Appendages and rig
attachment
ISO 12216, Small craft — Windows, portlights, hatches, deadlights and doors — Strength and watertightness
requirements
ISO 12217 (all parts), Small craft — Stability and buoyancy assessment and categorization
ASTM C393, Standard Test Method for Flexural Properties of Sandwich Constructions
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 boat 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 boats 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, e.g. hurricanes
NOTE For the application of this part of ISO 12215, the calculation wave height is 7 m.
3.1.2
design category B (“offshore”)
category of boats 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 boats 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
2 © ISO 2008 – All rights reserved

ISO 12215-5:2008(E)
3.1.4
design category D (“sheltered waters”)
category of boats 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
m
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 close hauled, as defined in ISO 8666 and
expressed in square metres
NOTE In the rest of this part of ISO 12215, non-sailing craft are considered as motor craft.
3.4
second moment of area
I
for a homogeneous material, it is the sum of the component areas multiplied by the square of the distance
from centre of area of each component area to the neutral axis, plus the second moment of area of each
component area about an axis passing through its own centroid, and is expressed in centimetres to the fourth
or millimetres to the fourth
NOTE The second moment of area is also referred to in other documentation as the moment of inertia and for brevity
as “second moment” within this part of ISO 12215.
3.5
section modulus
SM
for a homogeneous material, it is the second moment of area divided by the distance to any point from the
neutral axis at which the stress is to be calculated and is expressed in cubic centimetres or cubic millimetres
NOTE The minimum section modulus is calculated to the furthest point from the neutral axis.
3.6
displacement craft
craft whose maximum speed in flat water and m conditions, declared by its manufacturer, is such that
LDC
V
< 5
L
WL
3.7
displacement mode
mode of running of a craft in the sea such that its mass is mainly supported by buoyancy forces
NOTE This is the case if the actual speed in a seaway and m conditions is such that its speed:length ratio makes
LDC
the craft behave as a displacement craft.
3.8
planing craft
craft whose maximum speed in flat water and m conditions, declared by its manufacturer, is such that
LDC
V
W 5
L
WL
NOTE This speed:length ratio limit has been arbitrarily set up in this part of ISO 12215, but it may vary from one boat
to another according to hull shape and other parameters.
ISO 12215-5:2008(E)
3.9
planing mode
mode of running of a craft in the sea such that its mass is significantly supported by forces coming from
dynamic lift due to speed in the water
NOTE 1 A planing craft in calm water will run in planing mode.
NOTE 2 A planing craft may be obliged to significantly reduce its speed when the sea gets worse, running in that case
in displacement mode.
4 Symbols
Unless specifically otherwise defined, the symbols shown in Table 1 are used in this part of ISO 12215.
NOTE The symbols are shown in alphabetic order, not in order of appearance.
Table 1 — Symbols, factors, parameters
Symbol Unit Designation/meaning of symbol Reference/subclause
concerned
Principal craft data
A m Sail area in accordance with ISO 8666 ISO 8666
S
B m Chine beam 6.1
C
B m Beam of the hull ISO 8666
H
B m Beam of the fully loaded waterline at m ISO 8666
WL LDC
D m Depth of bulkhead 11.8.1
b
L m Length of the hull ISO 8666, 6.1
H
L m Length of the fully loaded waterline at m ISO 8666, 6.1
WL LDC
V knots Maximum speed at m 6.1
LDC
h m Load head for watertight bulkhead or integral tank 8.3
b
m kg Loaded displacement mass of the craft 3.2
LDC
β ° Deadrise angle at 0,4 L forward of its aft end 6.1, 7.3
0,4 WL
Panel or stiffener dimensions
A m Design area under consideration 7.5.1
D
b mm Shorter dimension of plate panel 9.1, 10
b mm Effective extent of plating connected to a stiffener 11.6
e
c mm Crown of a curved panel 10.1.3
c mm Crown of a curved stiffener 11.2.1
u
h m Height of centre of panel or mid stiffener above W 7.6
L
l mm Longer dimension of plate panel 9.1.2
l mm Unsupported span of stiffener or frame 9.2.2
u
s mm Stiffener or frame spacing 9.2.1
x m Distance of mid panel or stiffener from of aft end of L 7.4
WL
Z m Height of top of hull or deck angle above W 7.6
L
Calculation data: factor, pressures, parameters, stresses
A cm Shear area cross-section 11.4.1
W
4 4
I cm , mm Second moment of area 11.4.2
4 © ISO 2008 – All rights reserved

ISO 12215-5:2008(E)
Table 1 (continued)
Symbol Unit Designation/meaning of symbol Reference/subclause
concerned
k 1 Area pressure reduction factor 7.5
AR
k 1 Minimun value for k 7.5
AR MIN AR
k 1 Stiffener shear force correction in Table 21 11.7.2
AS
k 1 Curvature correction factor for plating 10.1.3
C
k 1 Curvature correction factor for stiffeners 11.2.1
CS
k 1 Design category factor 7.2
DC
k 1 Longitudinal pressure distribution factor 7.4
L
k 1 Structural component and boat type factor 7.5
R
k 1 Stiffener shear area factor 11.2.2
SA
k 1 Shear strength aspect ratio factor 10.5.4
SHC
k 1 Light and stable sailboat pressure correcting factor for slamming 7.8
SLS
k 1 Stiffener bending moment correction in Table 21 11.7.2
SM
k 1 Superstructure pressure reduction factor 7.7
SUP
k 1 Vertical pressure distribution factor 7.6
Z
k 1 Bending stiffness factor for sandwich 10.1.1
k 1 Panel aspect ratio factor for bending strength 10.1.2
k 1 Panel aspect ratio factor for bending stiffness 10.1.2
k 1 Sandwich minimum skin location factor 10.5.6
k 1 Sandwich fibre factor 10.5.6
k 1 Sandwich care factor 10.5.6
k , k 1 Minimum thickness factors 10.6.2
7 8
n 1 Dynamic load factor 7.3
CG
P kN/m Motorcraft bottom minimum pressure (planing or displacement) 8.1.2, 8.1.3
BM MIN
P kN/m Motorcraft bottom pressure in displacement mode 8.1.2
BMD
P kN/m Motorcraft base bottom pressure in displacement mode 8.1.2
BMD BASE
P kN/m Motorcraft bottom pressure in planing mode 8.1.3
BMP
P kN/m Motorcraft base bottom pressure in planing mode 8.1.3
BMP BASE
P kN/m Motorcraft side pressure in displacement mode 8.1.4
SMD
P kN/m Motorcraft side pressure in planing mode 8.1.5
SMP
P kN/m Minimum motorcraft side pressure (displacement or planing mode) 8.1.4, 8.1.5
SM MIN
P kN/m Motorcraft deck pressure 8.1.6
DM
P kN/m Motorcraft deck base pressure 8.1.6
DM BASE
P kN/m Minimum motorcraft deck pressure 8.1.6
DM MIN
P kN/m Motorcraft superstructure pressure 8.1.7
SUP M
P kN/m Sailing craft bottom pressure 8.2.1
BS
P kN/m Sailing craft bottom base pressure 8.2.1
BS BASE
P kN/m Minimum sailing craft bottom pressure 8.2.1
BS MIN
ISO 12215-5:2008(E)
Table 1 (continued)
Symbol Unit Designation/meaning of symbol Reference/subclause
concerned
P kN/m Sailing craft side pressure 8.2.2
SS
P kN/m Minimum sailing craft side pressure 8.2.2
SS MIN
P kN/m Sailing craft deck pressure 8.2.3
DS
P kN/m Sailing craft deck base pressure 8.2.3
DS BASE
P kN/m Minimum sailing craft deck pressure 8.2.3
DS MIN
P kN/m Sailing craft superstructure pressure 8.2.4
SUP S
P kN/m Design pressure, watertight boundaries 8.3.1
WB
P kN/m Design pressure, integral tank boundaries 8.3.2
TB
q N/mm Shear flow H.2.1.7, H.3.2
3 3
Q cm , mm First moment of area 11.4.1
3 3
SM cm , mm Section modulus 11.4.1
σ N/mm Design direct stress 10
d
σ N/mm Ultimate strength (flexural, compressive, tensile) 10
u
τ N/mm Design shear stress 10.5.4, 11
d
τ N/mm Ultimate shear strength 10.5.4, 11
u
E N/mm Elasticity modulus (flexural, compressive, tensile) 10.5, 11
w kg/m Dry fibre reinforcement mass per square metre 10.2.2, 10.5.6
ψ 1 Glass content in mass Annex A, Annex C
φ 1 Glass content in volume Annex A, Annex C
Other variables contained in annexes are not listed in this table.
5 General
The scantling determination shall be accomplished as follows:
⎯ for craft with a length L of 2,5 m up to 24 m, in accordance with Clauses 6 to 11;
H
⎯ for sailing craft with a length L of 2,5 m up to 9 m of design categories C and D, in accordance with
H
Annex A for plating;
⎯ for craft with a length L of 2,5 m up to 6 m and of single-skin construction, the drop test in Annex B may
H
be used as an alternative to the main body of this part of ISO 12215.
NOTE 1 These scantling requirements are based on normal anticipated sea loads during normal usage. Compliance
with these requirements does not eliminate the possibility of damage from accidental overloads, careless handling, trailing
loads, chocking loads, grounding or berthing. In some instances the requirements may come out lower than fabrication
requirements such as welding ability, and should therefore be increased accordingly. For craft < 6 m, in particular,
robustness criteria may be the governing aspect for scantling determination, e.g. beaching, grounding, trailer and fender
loads. See 10.5.6 and 10.6.
NOTE 2 Annex A is applicable mainly to small, lightweight inshore sailing boats and sailing dinghies that might
otherwise find the scantlings from other sections too conservative, but is only available for plating thickness assessment.
NOTE 3 If an annex is used as an alternative to Clauses 6 to 11, the boat builder shall still refer to parts 7 (multihulls),
8 (rudders) and 9 (appendages and rig attachment) of ISO 12215, as appropriate, in addition to using the particular annex.
6 © ISO 2008 – All rights reserved

ISO 12215-5:2008(E)
6 Dimensions, data and areas
6.1 Dimensions and data
All dimensions are measured, unless otherwise specified, in accordance with ISO 8666, with the craft in the
fully loaded condition, with a mass m (expressed in kilograms) as defined in 3.2.
LDC
The main dimensions are
⎯ L , the hull length in metres,
H
⎯ L , the length of the waterline, craft at rest in m conditions, in metres,
WL LDC
⎯ B , the chine beam, measured in accordance with Figure 1, at 0,4 L forward of its aft end, in metres,
C WL
⎯ β , the deadrise angle at 0,4 L forward of its aft end, measured according to Figure 1, not to be taken
0,4 WL
< 10°, nor > 30°, in degrees,
⎯ V, for motor craft, the maximum speed in calm water declared by the manufacturer, with the craft in m
LDC
conditions. This speed shall not be taken as < 2,36 L . For sailing craft, speed does not need to be
WL
declared in knots.
NOTE For round bilge, the outer limit or chine is considered at the point where a tangent at 50° from the horizontal is
tangent to the hull.
Figure 1 — Measurement of chine beam, B , and deadrise angle, β
C
6.2 Areas
6.2.1 General
The hull, deck and superstructure are divided into various areas: bottom, side, decks and superstructures (see
Figure 2).
6.2.2 Bottom areas
For all craft, bottom pressure applies up to waterline (see Figure 2).
The part of the transom following the above definition is considered as bottom.
ISO 12215-5:2008(E)
a) b)
c) d)
Key
1 bottom (hatched area)
2 side
3 deck
4 superstructures
5 superstructure top
6 hard chine
Figure 2 — Definitions of areas, and panel height above waterline
6.2.3 Side areas
The extent of the side pressure area, which includes the transom, is the part of the hull not considered as
belonging to the bottom area.
6.2.4 Decks and superstructures
Deck areas are parts of the deck exposed to weather and where persons are liable to walk. Cockpit bottom
and top of benches and seating areas are included.
Superstructure areas include all areas above deck level. Table 4 lists the different superstructure types.
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ISO 12215-5:2008(E)
6.2.5 Panel fully in one area or across two areas
The general situation is as follows:
1) where the plate panel or stiffener is fully within a specified design area, e.g. bottom, side, deck,
superstructures, etc., its design pressure shall be determined at the middle of the panel or at mid-length
of the stiffener;
2) where the plate panel or stiffener extends over both bottom area and side area, its design pressure shall
be determined as a constant pressure over the entire design area, calculated as a weighted average
between the two pressures, as shown in the following example.
EXAMPLE For a sailboat panel that lies 30 % in the bottom area and 70 % in the side area, the average pressure is
0,3 P + 0,7 P , where P is obtained at the midpoint of that part of the panel which lies above the waterline.
b s s
CAUTION — According to 8.1.1, for categories A and B planing motor craft, the side panels and
stiffeners shall be analysed both in planing and displacement mode, using the worst case. If the chine
is below waterline, the side panel is across side and bottom [see Figure 2 a)]. In that case, method 2)
above shall be used.
For large panels, see also 10.1.4.
7 Pressure adjusting factors
7.1 General
Final design pressure is adjusted by a set of factors according to design, boat type, location, etc.
7.2 Design category factor k
DC
The design category factor k , defined in Table 2, takes into account the variation of pressure loads due to
DC
sea with design category.
Table 2 — Values of k according to design category
DC
Design category A B C D
Value of k 1 0,8 0,6 0,4
DC
7.3 Dynamic load factor n
CG
7.3.1 General
The dynamic load factor n is considered to be close to the single amplitude acceleration measured at the
CG
craft centre of gravity at the relevant frequency for a certain period of time. This factor is the negative
acceleration supported by the craft, either while slamming in an encountered wave at speed or falling from the
crest of a wave into its trough. n is expressed in gs where 1g is the acceleration due to gravity (9,81 m/s ).
CG
ISO 12215-5:2008(E)
7.3.2 Dynamic load factor n for planing motor craft in planing mode
CG
The dynamic load factor for planing craft running in planing mode shall be determined from Equation (1) or
Equation (2).
⎛⎞
L VB×
WL C
(1)
n=+0,32 0,084× 50− β×
⎜⎟()
CG 0,4
10 ×Bm
CLDC
⎝⎠
where all data are previously defined.
NOTE 1 Equation (1) is derived from practical tests and is therefore not required to be dimensionally correct.
Where Equation (1) gives an n value u 3,0, the value given by Equation (1) shall be used.
CG
Where Equation (1) gives an n value > 3,0, that value or the value from Equation (2) shall be used.
CG
0,5 ×V
n = (2)
CG
0,17
m
LDC
In any case, n need not be taken > 7.
CG
NOTE 2 The limitation on n in this paragraph is due to the limitation of speed by the crew to keep the slamming
CG
accelerations within acceptable comfort and safety limits. The crew of “super sports” or racing boats accept a harder ride
than a family cruiser, but need special body support, shock damping seats or equipment to prevent injury from high gs.
7.3.3 Dynamic load factor n for sailing craft and displacement motor craft
CG
For sailing craft, n is not used for pressure determination. It is only used in the calculation of k for which
CG L
purpose the value of n shall be taken as 3. For motor craft where n , determined using Equation (1), is
CG CG
< 3,0 from Equation (1), a value of 3,0 shall still be used for calculation of k .
L
7.4 Longitudinal pressure distribution factor k
L
The longitudinal pressure distribution factor k takes into account the variation of pressure loads due to
L
location on the craft. It shall be taken from Figure 3 or calculated from Equation (3).
k is a function of the dynamic load factor defined below for motor craft.
L
1−×0,167 n x x
CG
kn=+ 0,167× but not taken > 1 for u 0,6 (3)
LCG
0,6 L L
WL WL
x
k = 1 for > 0,6
L
L
WL
where
n is determined in accordance with 7.3, but for the purposes of determination of k , n shall not
CG L CG
be taken < 3 nor > 6;
x
is the position of the centre of the panel or middle of stiffener analysed proportional to L ,
WL
L
WL
x
where = 0 and 1 are respectively the aft end and fore end of L .
WL
L
WL
where x is the longitudinal position of the centre of the panel or middle of stiffener forward of aft end of L in
WL
m conditions, in metres.
LDC
The overhangs fore and aft shall have the same value of k as their respective end of the waterline.
L
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ISO 12215-5:2008(E)
NOTE In the graph the only represented intermediate value of n between 3 and 6 is 4,5; for other intermediate
CG
values, k shall be determined either by calculation according to
...