RCD Workshop Manual

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RECREATIONAL CRAFT

DIRECTIVE

WORKSHOP MANUAL

2004

Copyright BMF 2004 Copyright BMF 2004

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Foreword

British Marine Federation Technical Department

This new Recreational Craft Directive Workshop Manual has been developed to incorporate a wealth of new material on interpretation, understanding and application of the Directive. A comprehensive resource combining the Workshop Manual with case studies and support information on the accompanying CDRom makes this the definitive reference for the Recreational Craft Directive.

We have done this by introducing a range of example boats to illustrate how the RCD applies to each of them. In each case, specific requirements for compliance with the RCD are considered, with an assumption that the harmonised standards are followed. We hope that these examples will help a builder building a similar style of boat to quickly identify the RCD essential

requirements that apply for that particular boat type

.

The manual also introduces the new requirements of the Amendment to the RCD, covering sound and exhaust emissions and amending some details of the original Directive.

Now that most of the Directive’s supporting standards are complete and harmonised it has been possible to provide detail on the requirements of these standards. Information on many of the

requirements in harmonised standards is included in the manual, including considerable detail from the stability and buoyancy standards for each example boat.

In order to avoid confusion between the Directive and the Manual the terms ‘Annex’ and ‘Section’ refer to annexes and sections as per the official Recreational Craft Directive. All other supplementary and additional information in this manual will be referred to as ‘Appendix’ or ‘Part’.

We acknowledge the help and co-operation of the following people and organisations: Mr Andrew Yates, Royal Yachting Association.

Mr Paul Handley, CEN consultant. Mr Tim Rowe, CE proof ltd.

British Standards Institution.

Department of Trade and Industry.

This Manual has been produced with an understanding of the Recreational Craft Directives 94/25/EC and 2003/44/EC as at March 2004. It has been compiled by the British Marine Federation with help from marine specialist consultants and Royal Yachting Association

Technical Department. It is based on practical experience and knowledge developed during the development and application of the Directives over the last six years. All boats vary and

allowance should be made for individual boat specifications. The Manual may not contain the latest interpretations and professional advice should be obtained before entering into any

commitment based upon this Manual.

Feedback on the procedures and techniques of application of the Directive and the format and layout of the Manual are welcomed and should be sent to BMF Technical Department.

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Part 1 INTRODUCTION TOTHE RCD WORKSHOP MANUAL

The principle aim of this manual is to provide information for boat builders that will assist them with the task of ensuring that their boats meet all the relevant requirements, both administrative and technical, for compliance with the Recreational Craft Directive. Reference to the Directive includes both the original RCD, 94/25/EC and the subsequent Amendment to the RCD,

2003/44/EC.

The approach followed is to state all the technical requirements of the RCD, known as Essential Requirements, to expand on these as necessary and to provide some detail on the relevant

harmonised standards that may be used to demonstrate compliance with each of these requirements.

To illustrate the application of the Directive in practice, a series of 11 example boats has been introduced, covering common boat types ranging from rowing tenders to offshore motor yachts, sailing dinghies to inland narrowboats.

For each example type the relevant requirements of the RCD are listed together with some of the requirements of the relevant harmonised standards. In particular, a detailed explanation of the relevant requirements for the application of BS EN ISO 12217 Stability and buoyancy has been given for each example boat type.

For installation requirements that are almost independent of boat type, such gas and electrical installations, the examples refer back to the main text of the manual, which provides a summary and some of the detail of the requirements of the relevant harmonised standards.

It is not possible within the scope of this manual to cover every detailed requirement of the harmonised standards and with this in mind the person responsible for compliance must ensure that he/she checks that all of the requirements of the most up to date version of the standard that has been followed. These standards are included on the CDRom and will be updated

periodically as new standards are published. Details of new standards can be obtained from British Standards Institution or BMF Technical Department.

Equally it has not been possible to cover every type of boat with a specific example, but it is nevertheless hoped that by studying an example of a similar type of boat, a boat builder will be able to quickly assess which requirements apply. The example boats are only intended to provide a guide to illustrate the most important considerations for RCD compliance for a range of boat types: although the Manual covers a good range it is unlikely that your boat will be the same in all respects so be careful to note differences that might result in further requirements…

When reading this manual remember that it does not include the full text of the Directive nor all the additional comments on the Directive published by the Commission and other authorities. The full text of the Directive is on the CDRom, together with many additional useful documents including the

Commission Comments, RSG Guidelines, UK Regulations and extracts from complementary resources such as the Merchant Shipping Act.

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Compliance with the essential requirements

The fundamental requirement for all boat builders is to ensure that their boats meet the Recreational Craft Directive’s Essential Requirements (ER). In this manual the harmonised standards are used to demonstrate compliance of the example boats with the ER, but other

methods and standards may be also used. However, those using alternative methods will have to ensure that they are able to clearly demonstrate how such methods meet the ER. This must be demonstrated to the satisfaction of the Notified Body where a third party is involved.

An established history of satisfactory performance, appropriately documented, can also be used t o show compliance if all Essential Requirements are met to current market expectations. Some of the examples suggest this approach where harmonised standards do not yet exist, for example in some cases for hull construction.

Harmonised standards

There are over 50 standards that are either complete and hence harmonised or currently being developed to support the Directive. All boatbuilding-specific harmonised standards and draft standards that are mandated to be harmonised, are given in the support material with details of their current status. Some standards are only relevant to equipment manufacture and testing and are not included on the CDRom. For further information on standards not included on the

CDRom please contact BMF Technical Department.

Many of these standards relate to components, different materials used in construction or are appropriate for different sizes or types of craft, and therefore only a relatively small number apply to any particular boat. The manufacturer of a large and probably complex craft may need to

focus on approximately 20 standards, a simple craft 10 or less. Inflatables, RIBs and PWCs have dedicated standards covering nearly all of the Directive’s requirements.

The example boats illustrate which harmonised standards are applicable for a range of boats. Some standards, such as those on craft identification coding (CIN) system, Principal data, Graphic symbols and Owner’s Manual are relevant for nearly all boats.

Other considerations

The RCD does not cover every element of the craft's construction and fit out (sails and rig on sailing craft for instance). However, the manufacturer is still responsible for all equipment fitted and other aspects of the craft under existing legislation. These elements must be included in the Owner’s Manual and technical details may be kept as an appendix to the Technical File.

General criteria

The boat builder is responsible for producing and keeping for 10 years a Technical File detailing how the boat meets the Essential Requirements of the Directive. The Technical File documents the choice of Design Category and the construction of the craft. The boat builder is responsible for applying a Craft Identification Number, a Builder’s Plate and the CE mark .

On placing on the market the craft must meet all relevant Essential Requirements of the Directive, including provision of an Owner’s Manual and a Declaration of Conformity.

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Part 2 SUMMARY OF THE RCD AND THE AMENDMENTS TO THE RCD

Regulations EC Directive 94/25/EC and Directive 2003/44/EC

UK Regulations SI 1996 No. 1353 and Amendment TBA

Status EC Directive 94/25/EC – In force (mandatory since 16 June 1998)

Directive 2003/44/EC – In force January 2005 with transitional period for PWCs and emissions.

Responsibility Lies with the company/person first putting the product on the European

Market i.e. the manufacturer or, if imported from outside Europe, the main importer.

Scope Applies to recreational craft from 2.5m to 24m hull length, including partly

completed boats and some components. RCD amendments apply to recreational craft and PWCs and include sound and engine exhaust emission requirements.

Exemptions Excludes boats intended solely for racing, canoes, gondolas, craft built for

own use and kept for a minimum of 5 years, etc. See Part 22.

Enforcing Trading Standards Officers are responsible for enforcing the Directive.

Authority

Penalties £5000 and/or 3 months in prison.

Compliance

Requirements The RCD and amendments require that when placed on the EU market for

the first time any boat within the scope of the Directive shall comply with the Essential Requirements (Annex I) and:

• have Technical Documentation (Annex XIII & Part 16) to show

that the boat complies with the Essential Requirements

• be built in accordance with the manufacturer’s Technical

Documentation

• be marked with a Craft Identification Number (Annex I, 2.1 &

Part 4)

• have a Builder’s Plate (Annex I, 2.2 & Part 4)

• have a CE mark to denote compliance (Article 10 & Part 21) on the

Builder’s Plate

• have an Owner's Manual (Annex 1, 2.5 and Info for OM)

• be provided with a Declaration of Conformity (Annex XV&

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• be assembled using components that are CE marked if listed in

Annex II (Part 15) or can be shown to meet the ERs of Annex I

• comply with sound and gas emission requirements ( Part 13 &

Part 14)

• satisfy the conformity assessment procedures (Part 18)

• comply with any other Directives that apply to them (Article 4.5)

e.g. Electro Magnetic Compatibility, Gas Appliances, Electrical Appliances (AC) Machinery, General Product Safety

Part complete boats

Part completed boats or kit boats must meet the compliance requirements listed above, as appropriate. They must meet the Essential Requirements up to the stage of completion when supplied and it must be possible to complete them in such a way that they will meet all the ERs when complete. Instead of a CE mark they must be sold with a declaration stating that the partly complete boat or kit met the Directive’s requirements up to the stage of completion when

supplied. (See Part 19). Inflatable boats

Inflatable boats and RIBs are covered by the RCD and must therefore meet the above list of compliance requirements and be CE marked. However, compliance may be demonstrated by complying with one relevant harmonised standard that is intended to support all of the relevant ERs. This harmonised standard is in three parts depending on the size and power of the

inflatable:

BS EN ISO 6185 Small craft Inflatable boats

-Part 1:2001 Boats with a motor maximum power rating of 4,5 kW

Part 2:2001 Boats with a motor power rating of 4,5 kW to 15 kW inclusive Part 3:2001 Boats with a motor power rating of 15 kW and greater

Currently inflatable boat standards only cover craft up to 8 m, however a part 4 to the standard for ‘ Boats greater than 8m overall length’ is proposed. Contact BMF Technical Department for further information.

PWCs

Personal watercraft (PWCs) must meet the design and construction requirements of the original directive and the emission requirements of the amending Directive and be CE marked. The design and construction requirements are covered in the harmonised standard BS EN ISO 13590 Personal watercraft – Construction and system installation requirements which, as for inflatable boats, is intended to cover nearly all the relevant ERs without the need to refer to other

harmonised standards. Components

Manufacturers of components listed in Annex II must ensure that these components meet the compliance requirements listed above, as relevant for the component, and CE mark them to show compliance. Part 15 provides more information on manufacture of components.

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Part 3 BOAT DESIGN CATEGORIES

Design category Wind force

(Beaufort scale)

Significant wave height (H 1/3, metres) A - ‘Ocean’ B - ‘Offshore’ C - ‘Inshore’ D - ‘Sheltered waters’ exceeding 8 up to, and including, 8 up to, and including, 6 up to, and including, 4

exceeding 4 up to, and including, 4 up to, and including, 2 up to, and including, 0,3 Definitions:

A. OCEAN: Designed for extended voyages where conditions may exceed wind force 8 (Beaufort scale) and significant wave heights of 4 m and above but excluding abnormal conditions, and vessels largely self-sufficient.

B: OFFSHORE: Designed for offshore voyages where conditions up to, and including, wind force 8 and significant wave heights up to, and including, 4 m may be

experienced.

C: INSHORE: Designed for voyages in coastal waters, large bays, estuaries, lakes and rivers where conditions up to, and including, wind force 6 and significant wave heights up to, and including, 2 m may be experienced.

D: SHELTERED WATERS: Designed for voyages on sheltered coastal waters, small bays, small lakes, rivers, and canals when conditions up to, and including, wind force 4 and significant wave heights up to, and including, 0,3 m may be experienced, with occasional waves of 0.5m maximum height, for example from passing vessels. Craft in each Category must be designed and constructed to withstand these

parameters in respect of stability, buoyancy, and other relevant essential requirements listed in Annex I, and to have good handling characteristics.

For Design Category A, unlimited wind and wave conditions apply as they reflect that a vessel engaged on a long voyage might incur any conditions and should be designed accordingly. The amended Directive now states that this is ‘excluding abnormal conditions’, which was added to make it clear that some extreme conditions need not be considered, such as a hurricane. In practice this still means that a Category A boat should be designed to be able to survive being caught out in gale and storm force winds at sea.

Most large sailing yachts that are designed for blue water cruising are, out of necessity, designed to be able survive such conditions and therefore Category A may be applicable. Very few motor cruisers are designed with such conditions in mind and most large offshore motor cruisers are therefore assigned to Category B.

For category D the wording has been changed slightly by the amendments to the Directive. The maximum significant wave height is now 0.3m, but allowance must be made for waves of passing vessels up to a maximum wave height of 0,5 m.

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It is important to note that the design category parameters are intended to define the physical conditions that might arise in any boat category for design evaluation. They are not intended for limiting the use of the recreational craft in any geographical areas of operation after it has been put into service.

The Commission has issued some additional guidance on the physical conditions, i.e. sea state, that should be considered from a design perspective for each category. It states that the physical conditions for each category are determined by the maximum wind strength and wave shapes, where the shape of the waves are consistent with waves generated by wind blowing at the maximum stated strength for a prolonged period, subject to limits of the i mplied fetch and the maximum stated wave heights, and excluding abnormal factors such as sudden change in depth or tidal races.

Put simply this means that that waves in Category D will be not only be small, but also of fairly regular shape, i.e. breaking waves are not envisaged, but for Category A the combination of severe winds and tall seas may result in very steep and even breaking waves.

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Part 4 IDENTIFICATION AND DOCUMENTATION

Craft Identification Number (CIN)

ER 2.1 Each craft shall be marked with an identification number including the following information:

- manufacturer’s code - country of manufacture - unique serial number - year of production - model year

Harmonised standard: BS EN ISO 10087:1996/A1:2000 Small craft – Hull identification –

Coding System (This standard is currently being revised to reflect the change from “Hull

Identification” to “Craft Identification” Coding System)

It should be noted that this is one of the few cases where the Directive refers specifically to ‘the relevant harmonised standard’ which implies that it is a requirement to use the harmonised standard rather than being optional. In practice this is limited to meeting a small number of requirements on placement of the number and size of characters used.

It should be noted that the Directive has been amended to refer to ‘craft’ rather than ‘hull’ identification and accordingly BS EN ISO 10087 is being revised to make it clear that the

requirement is for an identification number for the entire craft, not just for the hull. This may be relevant where manufacture of the hull is sub-contracted, but the CIN should reference the

manufacturer that completes the craft and takes responsibility for it under the RCD. Changes of detail of the actual identification requirements are not envisaged.

Make up of CIN

GB - ABC B7123 G 5 06 Country Code

*Manufacturer’s Identification Code Serial Number

**Month of Manufacture Year of Manufacture Model Year

*Manufacturer’s Identification Code (MIC). For professional builders in the UK the MIC is held on the BMF database. DIY builders should contact the RYA for a complete Craft Identification Number where “RYA” is used as the MIC.

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The CIN is to be made up of characters at least 6mm high and sited in a visible position on the starboard outboard side of the transom, or near the stern within 50mm of transom top, gunwale, hull/deck joint or capping. A duplicate CIN is to be affixed to a non-removable part of the craft in a hidden location.

Builder's Plate

ER 2.2 Each craft shall carry a permanently affixed plate mounted separately from the boat hull identification number, containing the following information:

- manufacturer’s name - CE marking

- boat design category according to section 1

- manufacturer’s maximum recommended load derived from section 3.6 excluding the weight of the contents of the fixed tanks when full

- number of persons recommended by the manufacturer for which the boat was designed to carry when underway .

Harmonised standard: BS EN ISO14945 Small craft - Builder’s plate (to be published 2004) Separate from the CIN, the boat must display a Builder’s Plate that clearly shows the information required by ER 2.2. The harmonised standard BS EN ISO 14945 Small craft - Builder’s plate provides details regarding the plate to ensure that information is always displayed in a standard recognisable format.

The information shown on the plate will vary depending on the type of boat, e.g. if it does/does not have an outboard engine, etc. To illustrate how this information varies examples of plates are given for each of the example boats in Appendix 1.

The information shown will always include the boatyard name, the Design Category, the

maximum number of persons and person symbol, the maximum weight that can be carried and the CE mark . A typical example is shown below:

Boatyard Name Manufacturer’s name

C Boat design category

Max 4

Maximum persons capacity

Max +

+ _=600kg Maximum recommended load(weight in kg)

CE XXX CE mark and notified body’s

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The line showing the person, suitcase and outboard symbols followed by a weight, shows the maximum total weight that can be added to the boat - 600kg for this example. This weight includes the outboard weight for outboard boats, but excludes the mass of the contents of any fixed fuel and water tanks when full.

The weight shown on the plate may therefore be different from the maximum recommended load used for loading and stability tests or calculations, which includes the weight of the content of all tanks. An explanation of the weight to be shown on the plate is given for each example boat. The boat builder must fix the Builder’s Plate in a clearly visible location on the boat before it leaves the manufacturer's control. The word ‘plate’ in this context is taken to include aluminium foil plates and vinyl stickers or markings on the hull surface, i.e. the required text and symbols may be moulded, printed, carved, stamped or otherwise indelibly marked on the hull.

According to BS EN ISO 14945 characters and/or symbols for the maximum number of people or maximum load shall be not less than 5 mm in height and other letters and numbers shall be not less than 3 mm in height. Symbols used should be as used for the examples.

It is possible for a boat to be simultaneously assigned more than one design category with

different maximum capacities for each category. If this route is followed the dif ferent criteria for each category should be clearly separated on the builders plate.

Owner's Manual

ER 2.5 Each craft shall be provided with an owner’s manual in the official Community language or languages, which may be determined by the Member State in which it is marketed in accordance with the Treaty. This manual should draw particular attention to risks of fire and flooding and shall contain the information listed in sections 2.2, 3.6 and 4 as well as the unladen

weight of the craft in kilograms.

Harmonised standard: BS EN ISO 10240:1996 Small Craft - Owner's manual.

The boat must be supplied with an Owner’s Manual that provides basic information on using it safely, as is the case for most other products on the market today. This information does not need to go into detail of all the skills required, e.g. how to sail or moor a boat, but may be limited to descriptions of specific features and recommended actions to use the boat safely, such as engine starting procedures, re-fuelling etc.

The harmonised standard BS EN ISO 10240:1996 Small Craft - Owner's manual summarises the typical contents for an Owner’s Manual and should be read by all boat builders. Individual

standards on stability, gas installations, etc. often contain an annex with more detailed requirements for information to be included in the Owner’s Manual specific to the subject covered. Throughout this manual references are also made to information that should be in the manual, including for the example boats.

The information in the Owner’s Manual must cover the safe operation of the craft with due consideration for the environment. It does not however have to include technical servicing information, such as wiring diagrams, fuel piping, etc., which may be included in another document separate from the Owner’s Manual. It should however contain ‘trouble shooting’ advice e.g. how to change the engine fuel filter. Even where a standard requires descriptions,

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drawings, and diagrams, some of this information may be omitted from the Owner’s Manual if included in a separate technical servicing document.

If a boat is to be exported, the Owner’s Manual supplied with it must be translated into the language of the country where it is placed on the market. If a technical service document is

supplied in addition to the manual it does not need to be translated. Equipment manuals supplied in addition to the manual also do not need to be translated.

A generic Owner’s Manual, i.e. one that applies for a range of boats, is acceptable provided that it contains all the required information for each model covered. It may also have provisions for filling out specific model information by hand.’

A copy of the Declaration of Conformity (Part 17), must also be included with the Owner’s Manual.

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Part 5 CONSTRUCTION

Hull structure

ER 3.1 The choice and combination of materials and its construction shall ensure that the craft is strong enough in all respects. Special attention shall be paid to the design category according to section 1 and the manufacturer’s maximum recommended load in accordance with section 3.6. Harmonised standard: BS EN ISO 12215 Small craft - Hull construction - Scantlings

Part 1:2000 Materials: Thermosetting resins, glass fibre reinforcement, reference laminate. Part 2:2002 Sandwich construction

Part 3:2002 Steel, wood, aluminium, other materials Part 4:2002 Workshop and construction

Part 5: draft Design pressures, allowable stresses, scantling determination (under validation) Part 6: draft Details of design and construction (under validation)

Part 7: draft Scantling determination of multihulls (under validation) Part 8: draft Rudder stocks and bearings (under validation)

Part 9: draft Appendages and rig attachments (under validation)

The harmonised standard BS EN ISO 12215 Hull construction - Scantlings is in nine parts, some of which are still under development. Parts 7, 8 & 9 are at a very early stage of drafting and are not yet suitable for use, Part 5 and 6 are expected to be published in 2005. For further

information and updates Contact BMF Technical Department.

Application and use of standards

The latest draft of EN ISO 12215 Part 5, includes an annex containing simplified methods for calculating the scantlings of motorboats and sailing boats with a hull length of less than 12m of design categories C and D. (See Annex A in standard).

Scantlings may be quickly obtained from this annex for construction of single-skin GRP, GRP with bulking material (eg Coremat), GRP sandwich (topsides and deck only), mild steel,

aluminium alloy, plywood or strip planking.

Two approaches are provided in this simplified annex. The first is the use of graphs that apply for motor and sailing boats of category C or D up to 12m length. The graphs show the required skin thickness in single-skin GRP per millimetre of frame spacing, so for a frame spacing of 400mm the thickness coefficient given by the graph must be multiplied by 400 to get t he required thickness in GRP. For motorboats the length and maximum speed of the boat are entered in the graph to get thickness and for sailing boats just the boat length is required.

The second method applies only to small sailing boats, up to 9m length. This method was introduced as the scantlings obtained from the graphs for small sailing boats can be very conservative, particularly for light sailing boats, as the graphs are based on length only. This alternative method provides the skin thickness in single-skin GRP for sailing boats from a short equation using the loaded displacement of the boat (weight with all people, equipment on board and full tanks).

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The thickness obtained for single-skin GRP by the simplified methods can then be converted to the thickness required for other materials by using simple conversion factors. For example, the hull skin thickness required for strip-plank wood construction is simply 2.5 times the thickness obtained for single skin GRP (e.g. 20mm strip plank could be used instead of 8mm GRP).

Similarly the required thickness for the basic GRP laminate may be altered if more woven roving is used or bulking material such as Coremat are added. Thickness can also be easily converted to the quantity of glass reinforcement required for a specified resin ratio.

Note: The methods given in Annex A are new drafts and are still under evaluation. Although it is hoped that they will prove very helpful in the long term they should be treated with caution until the standard is approved. Updates will be given via BMF website.

Where the harmonised standard is not adopted, a number of other approaches can be followed to demonstrate compliance with the scantling rules:

1. The structural requirements of the hull may be assessed by other acceptable scantling

determination methods that are applicable to the boat type, design category and the

maximum recommended load. Typical classification society rules for small craft include those from Lloyds Register, ABS, DNV and RINA.

2. Construction calculation(s) from other published methods for determining small craft

scantlings or from engineering principals. All calculations must be documented.

3. Trials and/or testing (e.g. drop test). Details of trials or testing shall be documented.

4. In some cases empirical knowledge, i.e. established service history without problems, can

be used to demonstrate the structural adequacy of the hull. This empirical knowledge must be documented.

5. Comparison of structure with another similar boat with a known acceptable service

history. The rationale supporting the comparison method must be documented.

For most boats over approximately 6m length, the calculation of strength using a scantling determination method is likely to be the preferred method, possibly backed up by some trials. For a small boats, typically less than 6m length, there are not many scantling rules in existence other than ISO 12215-5 that are suitable and therefore assessment of the structure could be

carried out by physical trials. A series of ‘test to near destruction’ trials could be devised, where the boat is tested with a load exceeding the maximum recommended load and in conditions (wind and sea state) exceeding that of the assigned Design Category. If the boat showed no signs of deterioration or damage from such tests this could be used to demonstrate compliance with the structural requirements: these tests and the results must be well documented in the Technical File. ISO 12215-5 includes a ‘drop test’ method of demonstrating compliance, applicable for boats of single-skin construction. To test, the boat is lifted, fully loaded, and dropped from a prescribed height. It must survive without visible damage. This drop test method has been used to assess the structure of RIBs for many years and would probably provide a practical test for determining compliance of a small boat.

Whatever method is used to demonstrate compliance with the structural requirements the

justification, including details of any trials, comparison, test or calculation must be documented and included in the Technical Documentation for the boat. This documentation could be partly in the form of a video or photographic record if trials are conducted.

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Separate from the requirement to document how the boat demonstrates compliance with the essential requirements, a record of the construction specification and method must be included in the Technical Documentation. This would include the construction plans and all material and construction details for a large boat but could be limited to a laminating schedule, if applicable, with material quantities and possibly a photographic record of the construction for a small boat.

Doors, windows and hatches

ER 3.4 Openings in hull, deck(s) and superstructure shall not impair the structural integrity of the craft or its weather tight integrity when closed.

Windows, portlights, doors and hatch covers shall withstand the water pressure likely to be encountered in their specific position, as well as point loads applied by the weight of persons moving on deck.

Harmonised standard: BS EN ISO 12216:2002 Small Craft – Windows, portlights, hatches, deadlights and doors - Strength and tightness requirements

Strength requirements for doors, windows, hatches and other opening appliances are covered by the harmonised standard BS EN ISO 12216:2002 Windows, portlights, hatches, deadlights and

doors - Strength and tightness requirements. The requirement to ensure watertight integrity

when closed, as applicable to the position of the appliance and intended use of the boat (Design Category), is also covered by the standard.

If a commercially available appliance, such as a standard production hatch, is to be fitted, then the boat builder need only ensure that this hatch has been CE marked for RCD compliance by its manufacturer (as a component covered by Annex 2) and is fitted as required by its manufacturer. The hatch manufacturer would have the responsibility for ensuring that this component has

adequate strength and watertight integrity if fitted correctly, and would normally refer to BS EN ISO 12216 to ensure compliance of its strength and other requirements. Note that as the

requirements for appliances vary according to Design Category, type of boat and position, the boat builder must ascertain that the CE marked hatch is suitable for use on the boat in its intended position. Information on this should be provided by the hatch manufacturer.

If a boat builder makes a custom appliance for the boat, such as a door or window, then the boat builder has the responsibility for compliance of the item with ESR 3.4, even if the manufacture of the item is sub-contracted. In such cases the boat builder would normally be expected to refer to BS EN ISO 12216 for the strength and watertightness requirements. The appliance is not be CE marked: it will be covered within the CE marking of the boat.

When using BS EN ISO 12216 the boat builder should note that the standard’s requirements vary depending on the location of the appliance on the boat, the Design Category and the type of boat – power or sailing. The thickness of window plating also varies depending on the plating material and type of edge connection used to secure the plate to the boat. Subject to these considerations the minimum thickness for plates may be either calculated or found from tables in the standard. The following summarises some of the requirements of the standard:

• There shall be no sliding appliances on the hull

• Flexibly connected plates (car windscreen types) may be used only on the superstructure

for Category C and D.

• Windows in superstructure should be water tight to degree 3 - Except Category D.

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The thickness required by the standard for a window of any size and of

The thickness required by the standard for a window of any size and of most common materialsmost common materials can be found by using the pre-ca

can be found by using the pre-calculated tables in the standard. lculated tables in the standard. To do this, first the basic designTo do this, first the basic design pressure must be taken from the table below for the type o

pressure must be taken from the table below for the type of boat and position of the window. f boat and position of the window. TheThe position is defined by one of four main

position is defined by one of four main areas, corresponding to: Area 1 – Hull, Area II – areas, corresponding to: Area 1 – Hull, Area II – Deck Deck and cabin tops, Area III - Superstructure sides a

and cabin tops, Area III - Superstructure sides and Area IV – other area. nd Area IV – other area. More detailedMore detailed definitions of these areas and illustrations are

definitions of these areas and illustrations are given in the standardgiven in the standard.. The table below also splits Area III requirements for the

The table below also splits Area III requirements for the superstructure front and sides (highersuperstructure front and sides (higher requirement for front).

requirement for front).

As an example, for a Category B motorboat window on the front

As an example, for a Category B motorboat window on the front of the cabin the basic designof the cabin the basic design pressure is 9 (kPa) from the table below.

pressure is 9 (kPa) from the table below.

Basic design pressure Basic design pressure p p Application

Application location area location area

I

I IIb IIb IIb IIb IIb IIb IIa IIa III III III III III III III III III III III III III III III III IV IV IVIV B

Booaat t ttyyppe e AAnny y AAnnyy AAnny y AAnny y AAnnyy SSaaiill SSaaiill MMoottoorr MMoott or or Mot Mot or or Mot Mot or or Mot Mot or or Mot Mot or or S Saaiill MMoott or or Design Design category category A Anny y A A B B CC,,D D AAnnyy AA, , BB CC, , DD A A B B A A B B C C D D AAnnyy AAnnyy Particular Particular (front, side, (front, side, any) any) A Anny y AAnnyy AAnny y AAnny y AAnnyy AAnnyy AAnnyy FFrroonntt FFrroonn tt S

Siiddee SSiidde e AAnny Ay Annyy AAnnyy AAnnyy

Pressure

Pressure kPa kPa 70 70 70 70 50 50 28 28 28 28 18 18 12 12 12 12 9 9 9 9 6 6 6 6 6 6 12 12 66 From the table below the thickness required for a tempered glass window of width 1000mm and

From the table below the thickness required for a tempered glass window of width 1000mm and height 700mm would be 5.7mm for this press

height 700mm would be 5.7mm for this pressure. ure. This has to be rounded to the nearest mm, soThis has to be rounded to the nearest mm, so the window fitted would have to have a minimum nominal thickness of 6mm.

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Thickness of semi-fixed plates for calculation specification T 9 (TG and P = 9 kPa) Thickness of semi-fixed plates for calculation specification T 9 (TG and P = 9 kPa)

A

A Values of b (lesser dimension)Values of b (lesser dimension) mmmm

mm mm 1010 0 0 1 1550 0 22000 0 22550 0 33000 0 33550 0 44000 0 445500 550000 555500 660000 665500 770000 775500 88000 0 99000 0 11 000 000 1 1 100 100 1 1 200 200 250 250 300 300 350 350 400 400 450 450 500 500 550 550 600 600 4,0 4,0 4,14,1 650 650 In this In this Area Area t t == t t minmin = = 4 mm 4 mm see see Table Table 5 5 4,1 4,2 4,3 4,4 4,1 4,2 4,3 4,4 700 700 4,0 4,0 4,3 4,3 4,4 4,4 4,5 4,5 4,6 4,6 4,64,6 750 750 4,1 4,1 4,4 4,4 4,6 4,6 4,7 4,7 4,8 4,8 4,9 4,9 4,94,9 800 800 4,2 4,2 4,5 4,5 4,7 4,7 4,9 4,9 5,0 5,0 5,1 5,1 5,1 5,1 5,25,2 900 900 4,0 4,0 4,3 4,3 4,6 4,6 4,9 4,9 5,1 5,1 5,3 5,3 5,5 5,5 5,6 5,6 5,6 5,6 5,75,7 1 1 000 000 4,0 4,0 4,4 4,4 4,7 4,7 5,1 5,1 5,3 5,3 5,6 5,6 5,7 5,7 5,9 5,9 6,0 6,0 6,1 6,1 6,16,1 1 1 100 100 4,0 4,0 4,4 4,4 4,8 4,8 5,2 5,2 5,5 5,5 5,7 5,7 6,0 6,0 6,1 6,1 6,3 6,3 6,5 6,5 6,6 6,6 6,66,6 1 1 200 200 4,1 4,1 4,5 4,5 4,9 4,9 5,2 5,2 5,6 5,6 5,9 5,9 6,1 6,1 6,3 6,3 6,5 6,5 6,8 6,8 6,9 6,9 7,0 7,0 6,96,9 1 1 300 300 4,1 4,1 4,5 4,5 4,9 4,9 5,3 5,3 5,6 5,6 6,0 6,0 6,2 6,2 6,5 6,5 6,7 6,7 7,0 7,0 7,2 7,2 7,3 7,3 7,37,3 1 1 400 400 4,1 4,1 4,5 4,5 4,9 4,9 5,3 5,3 5,7 5,7 6,0 6,0 6,3 6,3 6,6 6,6 6,9 6,9 7,2 7,2 7,5 7,5 7,6 7,6 7,77,7 1 1 500 500 4,1 4,1 4,5 4,5 5,0 5,0 5,4 5,4 5,7 5,7 6,1 6,1 6,4 6,4 6,7 6,7 7,0 7,0 7,4 7,4 7,7 7,7 7,9 7,9 8,08,0 1 1 600 600 4,1 4,1 4,6 4,6 5,0 5,0 5,4 5,4 5,8 5,8 6,1 6,1 6,5 6,5 6,8 6,8 7,1 7,1 7,5 7,5 7,9 7,9 8,1 8,1 8,38,3 1 1 800 800 4,1 4,1 4,6 4,6 5,0 5,0 5,4 5,4 5,8 5,8 6,2 6,2 6,6 6,6 6,9 6,9 7,2 7,2 7,7 7,7 8,2 8,2 8,5 8,5 8,78,7 2 2 000 000 4,1 4,1 4,6 4,6 5,0 5,0 5,4 5,4 5,9 5,9 6,2 6,2 6,6 6,6 7,0 7,0 7,3 7,3 7,9 7,9 8,4 8,4 8,8 8,8 9,09,0 Circular flat plate

Circular flat plate

Values of

Values of d d in millimetresin millimetres

10 10 0 0 1 1550 0 22000 0 22550 0 33000 0 33550 0 44000 0 445500 550000 555500 660000 665500 770000 775500 88000 0 99000 0 11 000 000 1 1 100 100 1 1 200 200 t t ==t t minmin 4,0 4,2 4,5 4,7 5,2 5,6 6,0 6,34,0 4,2 4,5 4,7 5,2 5,6 6,0 6,3

For a side window (basic design pressure is 6 (kPa) from fir

For a side window (basic design pressure is 6 (kPa) from fir st table) of tempered glass and thest table) of tempered glass and the same dimensions the required thickness would be 5mm (4.7 rounded up) from the following same dimensions the required thickness would be 5mm (4.7 rounded up) from the following table.

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Thickness of semi-fixed plates for calculation specification T 6 (TG and P = 6 kPa) Thickness of semi-fixed plates for calculation specification T 6 (TG and P = 6 kPa)

Rectangular flat plate Rectangular flat plate

A

A Values of b (lesser dimension)Values of b (lesser dimension) mmmm mm mm 1010 0 0 1 1550 0 22000 0 22550 0 33000 0 33550 0 44000 0 445500 550000 555500 660000 665500 770000 775500 88000 0 99000 0 11 000 000 1 1 100 100 1 1 200 200 250 250 300 300 350 350 400 400 450 450 500 500 550 550 600 600 650 650 In this In this Area Area t t ==t t minmin== 4 mm 4 mm see see Table 5 Table 5 700 700 750 750 4,0 4,0 4,04,0 800 800 4,0 4,0 4,1 4,1 4,2 4,2 4,2 4,2 4,24,2 900 900 4,0 4,0 4,2 4,2 4,3 4,3 4,5 4,5 4,5 4,5 4,6 4,6 4,64,6 1 1 000 000 4,1 4,1 4,3 4,3 4,5 4,5 4,7 4,7 4,8 4,8 4,9 4,9 5,0 5,0 5,05,0 1 1 100 100 4,2 4,2 4,5 4,5 4,7 4,7 4,9 4,9 5,0 5,0 5,1 5,1 5,3 5,3 5,4 5,4 5,35,3 1 1 200 200 4,0 4,0 4,3 4,3 4,5 4,5 4,8 4,8 5,0 5,0 5,2 5,2 5,3 5,3 5,5 5,5 5,7 5,7 5,7 5,7 5,75,7 1 1 300 300 4,0 4,0 4,3 4,3 4,6 4,6 4,9 4,9 5,1 5,1 5,3 5,3 5,5 5,5 5,7 5,7 5,9 5,9 6,0 6,0 6,06,0 1 1 400 400 4,0 4,0 4,4 4,4 4,6 4,6 4,9 4,9 5,2 5,2 5,4 5,4 5,6 5,6 5,9 5,9 6,1 6,1 6,2 6,2 6,36,3 1 1 500 500 4,1 4,1 4,4 4,4 4,7 4,7 5,0 5,0 5,2 5,2 5,5 5,5 5,7 5,7 6,0 6,0 6,3 6,3 6,5 6,5 6,56,5 1 1 600 600 4,1 4,1 4,4 4,4 4,7 4,7 5,0 5,0 5,3 5,3 5,5 5,5 5,8 5,8 6,2 6,2 6,5 6,5 6,7 6,7 6,86,8 1 1 800 800 4,1 4,1 4,4 4,4 4,8 4,8 5,1 5,1 5,4 5,4 5,6 5,6 5,9 5,9 6,3 6,3 6,7 6,7 6,9 6,9 7,17,1 2 2 000 000 4,1 4,1 4,4 4,4 4,8 4,8 5,1 5,1 5,4 5,4 5,7 5,7 6,0 6,0 6,4 6,4 6,8 6,8 7,1 7,1 7,47,4 Circular flat plate

Circular flat plate Values of

Values of d d in millimetresin millimetres 10 10 0 0 1 1550 0 22000 0 22550 0 33000 0 33550 0 44000 0 445500 550000 555500 660000 665500 770000 775500 88000 0 99000 0 11 000 000 1 1 100 100 1 1 200 200 t t ==t t minmin 4,2 4,2 4,6 4,6 4,9 4,9 5,25,2

From a further table it

From a further table it can be found that the required thickness for the same size side window incan be found that the required thickness for the same size side window in polycarbonate would be 8mm.

polycarbonate would be 8mm.

The thickness requirements from the tables

The thickness requirements from the tables also apply to doors and also apply to doors and hatches, again dependent onhatches, again dependent on material and location.

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Anchoring, mooring and towing points

ER 3.9 All craft, taking into account their design category and their characteristics shall be fitted with one or more strong points or other means capable of safely accepting anchoring, mooring and towing loads.

Harmonised standard: BS EN ISO 15084:2003 Small craft Anchoring, mooring and towing -Strong points

All boats must have one or more attachment point strong enough to take the loads of anchoring, mooring or being towed. The harmonised standard BS EN ISO 15084 Anchoring, mooring and

towing - Strong points provides details for the location, number and strength of such strong

points.

The position and number of points specified by BS EN ISO 15084 can be summarised as follows:

• Craft under 6 m LH - at least one point forward for anchoring, mooring or towing

• Craft over 6 m LH - at least one additional mooring point aft

• Craft over 12 m LH -at least one additional mooring point both forward and aft

• Craft over 18 m LH - at least one additional mooring point both port and starboard.

For small boats and dinghies the requirement for only one point, positioned forward, might typically be met by eye or ring on the bow for the painter or towing line.

Strength requirements are also set by BS EN ISO 15084. The standard requires that each strong point shall be designed and constructed so that it can take a horizontal load of P without failure of the strong point or the surrounding structure to which it is attached, where:

(

P1 = f ⋅ 4 3

.

⋅L_C−5 4

.

)

.

)

.

kN forward points, for anchoring and being towed

(

P2 = f ⋅ 3 5

.

⋅L_C−4 3 kN forward points, for mooring

(

P3 = f ⋅ 3 0

.

⋅L_C−3 8 kN aft points,

where f = 1.0 for Categories A and B, 0.9 for Category C or 0.75 Category D

and LCis the calculation length to be taken as

2 WL H C L L L = +

BS EN ISO 15084 adds that the breaking strength of a strong point for any application need not be higher than that required to withstand a load representing the mass of the boat in the fully

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Part 6 STABILITY, BUOYANCY and LOADING Maximum number of persons

From ER 2.2, the Builder’s Plate shall include the - number of persons recommended by the manufacturer for which the boat was designed to carry when underway.

ER 2.2 requires that the manufacturer’s maximum recommended number of persons that the boat is designed to carry when underway is shown on the Builders Plate, and according to ER 2.5 this number must also be stated in the Owner’s Manual. This maximum recommended number of persons is also an important piece of information to be incorporated in the stability and buoyancy calculations.

The maximum number of persons may be limited by either or both, t he amount of practical seating space available or the maximum weight that can be safely carried, both of which need to be applied.

The harmonised standard BS EN ISO 14946 Maximum Load capacity defines a ‘seat’ as any surface where a person may sit with minimum dimensions of 400 mm width by 750 mm length, i.e. depth of the seat plus clear space for legs in front of the seat, and recommends that the width be 500 mm. For cases where a seat is not provided it defines ‘seating area’ as clear cockpit sole space of area 750 mm by 500 mm for each person. For small boats and dinghies the deck area beside the cockpit may be considered as the seats.

The maximum recommended number of persons must not exceed the number of seats/seating spaces available when measured according to these definitions. However for larger boats the sensible limit on the number of persons is likely to be far less than the number from a calculation based on the available area.

Maximum recommended load

ER 3.6 The manufacturer’s maximum recommended load (fuel, water, provisions, miscellaneous equipment and people (in kilograms)) for which the boat was designed shall be determined according to the design category (section 1), stability and freeboard (section 3.2) and buoyancy and flotation (section 3.3).

Harmonised standard: BS EN ISO 14946 - Small craft - Maximum load capacity

The manufacturer must recommend a maximum weight of load, which shall include the weight of all items and persons (see above), that can be safely added to the empty boat without it being overloaded.

The items to be included in this maximum recommended load are listed in ER 3.6, as quoted above, and defined in more detail in the harmonised standard BS EN ISO 14946 Small craft - Maximum load capacity.

It is the manufacturer’s responsibility to recommend the maximum load weight based on

experience and any relevant design considerations. This recommended figure is required to be verified by the stability and buoyancy tests of BS EN ISO 12217 and should be included in the Owner’s Manual, together with an explanation of its significance and the safety implications of exceeding it.

BS EN ISO 14946 states that the maximum load shall include the weight of the f ollowing: a) the number of persons at 75 kg each (for adults - where children are carried as part of the

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b) basic equipment of ( LH– 2.5)2, but not less than 10 kg,

c) stores and cargo (if any), dry provisions, consumable liquids and miscellaneous equipment not included in the light craft mass or in clause b above,

d) consumable liquids (fresh water, fuel) in portable tanks filled to the maximum capacity, e) consumable liquids (fresh water, fuel) of permanently installed tanks filled to the maximum

capacity,

f) a liferaft or dinghy when intended to be carried.

The maximum load weight calculated in this way is the Maximum Total Load (m_MTL) to be used

in the stability and buoyancy calculations. A breakdown of this maximum load should be included in the Owner’s Manual and for larger boats information regarding the vertical distribution of load may also be important.

The weight given in the Owner’s Manual for the maximum load and used for calculations might be different from the weight stated on the Builder’s Plate. For safety reasons to avoid this being

mistaken as weight allowance for luggage and other carry-on gear, the weight of all liquids in fixed fuel and water tanks is excluded from the weight shown on the Builder’s plate.

When considering the maximum load that can be added to the empty boat, the empty boat is defined as the boat in the light craft condition as defined in BS EN ISO 8666. For outboard powered boats, this is the weight of the empty boat plus the weight of an outboard of the maximum recommended size. Accordingly the outboard weight is not included in the maximum load, but it is included in the weight shown on the Builder’s plate.

The important consideration to remember when assessing the boat weight and maximum load weight is that the following must always apply:

Loaded Displacement M ass (m_LDC) = Light Craft Mass + Maximum Total Load (m_MTL)

where the Light Craft Mass is as defined in BS EN ISO 8666 and the Maximum Total Load (m_MTL)

is the manufacturer’s maximum recommended load as defined above. The Loaded Displacement M ass (m_LDC), which is the sum of these two weights, is the weight of the boat in the fully loaded

condition which is to be considered in the stability tests and calculations. In the examples, example weights are provided for the sample boats.

Stability, Freeboard and Buoyancy

ER 3.2 The craft shall have sufficient stability and freeboard considering its design category according to section 1 and the manufacturer’s recommended load according to section 3.6.

ER 3.3 The craft shall be constructed to ensure that it has buoyancy characteristics appropriate to its design category according to section 1.1, and the manufacturer’s maximum recommended load according to section 3.6. All habitable multihull craft shall be so designed as to have sufficient buoyancy to remain afloat in the inverted position.

Boats of less than six meters in length that are susceptible to swamping when used in their design category shall be provided with appropriate means of flotation in the swamped condition.

The harmonised standard: BS EN ISO 12217 Small craft - Stability and buoyancy - assessment and categorisation sets requirements relating to the minimum freeboard, stability and buoyancy, as appropriate for the type of boat.

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Part 1:2002 Non-sailing boats of hull length greater than or equal to 6m. Part 2:2002 Sailing boats of hull length greater than or equal to 6m. Part 3:2002 Boats of hull length less than 6m.

For inflatable boats and RIBs up to 8m L H assessments should be carried out using BS EN ISO

6185 Small craft - Inflatable boats, RIBs over 8m should use BS EN ISO 12217-1 for the stability assessment.

BS EN ISO 12217 Part 1: Non-sailing boats of hull length greater than or equal to 6m This part of the stability standard covers “the stability and buoyancy of non-sailing boats of hull length greater or equal to 6 m”. It offers one option for the assessment for Design Category A (Ocean) and B (Offshore) boats built with full watertight deck, quick draining cockpits and small deck recesses, one option for Design Category B (Offshore) boats with any form of deck and various options for Design Category C (Inshore) and D (Sheltered water) boats.

These options mean that a vessel without a full watertight deck, quick draining cockpits and small deck recesses can never be assigned with a Design Category A and will only ever be assigned Category B if it is able to float with a required level of reserve buoyancy when fully swamped. The criteria for assessment for each option is detailed in the BS EN ISO 12217-1 and depending on the type of craft and design category requires the assessment of the some of the crit eria

detailed below.

Downflooding Height Measurement & Assessment

All options address the risk of downflooding which is the risk of water entering non-draining parts of a boat. The size and position of openings in the hull and their height, or in an open boat, the gunwale height above the water level must be greater than a given limit. Engine exhausts, discharges connected to watertight systems (bilge outlet for example) and openings that are provided with a watertight means of closure are not considered, although the companionway is always considered open however watertight it may be. The full procedure is detailed in the

standard and involves measuring the height of openings above the loaded waterline with the boat

at the Loaded Displacement M ass (m_LDC).

BS EN ISO 12217-1 gives tables with the required limits for the downflooding height which depend on the Design Category and length of the craft. If the craft does not meet these values given in the tables a more detailed calculation provided in Annex A (Full method for required downflooding height) may be used to demonstrate compliance with the standard.

Downflooding Angle

This requirement is to show that there is sufficient margin of heel angle before significant

quantities of water can enter the boat. A simply method of calculating this is provided in BS EN ISO 12217-1, Annex C (Methods for calculating downflooding angle) and similarly to the

downflooding height, if this method does not show compliance with the requirements, practical testing or computer simulation may provide an alternative method.

Offset Load Test

This test demonstrates sufficient stability for the boat at loaded displacement mass against offset loading by the crew. BS EN ISO 12217-1, Annex B (Method for offset-load test) gives the

procedure for conducting the test with the maximum allowable heel angle that may be obtained which is a function of length given in Clause 6.2 of the standard.

Resistance to Waves & Wind (Categories A & B only)

These calculations require a righting moment curve (for a more detailed explanation of these, see the section on BS EN ISO 12217-2) for the craft in the minimum operating condition unless the ratio of the Loaded Displacement/Minimum Operating Condition >1.15 in which case the curve

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for the loaded displacement shall also be assessed. Righting moment curves are normally

produced by the designer or a naval architect from the lines plan with an inclining experiment on the completed boat and addresses the forces likely to be applied and the energies dissipated when a boat is rolling in beam waves and wind.

Heel due to Wind Action (Category C and D)

This is only a requirement for boats where the windage profile is greater than LHBH. The standard

gives limits for the maximum heel angle resulting from the application of a wind heeling

moment. The purpose of the test or calculation is to show that the actual angle of heel is less than the assumed maximum. If performed by practical test, the maximum moment required for the calculation is the maximum offset load moment.

Like the resistance to wind and waves calculation these calculations should be carried out for the craft in the minimum operating condition unless the ratio of t he Loaded Displacement/Minimum Operating Condition >1.15 when the calculation should be calculated in both conditions.

Floatation Requirements

Depending on the assessment schedule used from Table 2 of BS EN ISO 12217-1 a floatation test may be required for open boats to demonstrate adequate swamped buoyancy and stability. These are detailed in Annex E (Method for level floatation test) and Annex F (Floatation material and elements).

BS EN ISO 12217 Part 2: Sailing boats of hull length greater than or equal to 6m

Part 2 of the standard covers “the stability and buoyancy of sailing boats of hull length greater or equal to 6 m”. Like Part 1 it offers an option for the assessment for Design Category A (Ocean) and B (Offshore) boats built with full watertight deck, quick draining cockpits and small deck recesses, and various options for Design Category C (Inshore) and D (Sheltered water) boats. The assessment requirements for each option is detailed in BS EN ISO 12217-2 and depending on the type of craft the assessment looks at different criteria. The main criteria, which can be used for assessment for any design categories, is the AVS (Angle of Vanishing Stability) related to it’ s mass and STIX calculation which requires a righting lever curve.

A righting lever curve is generated by plotting a stationary (static) boat’s righting lever against its angle of heel. The lever is the horizontal distance between the boat’s centre of gravity (CG) and a vertical line through its centre of buoyancy (CB). This lever is known as GZ and that’s why the stability curve is often called a GZ curve.

When upright, the CG will be in the same vertical line as the CB (usuall

ever n aves), ill ing l the y the centreline) and so there is no righting l i.e. GZ=Zero. But, whe a boat heels (through the action of wind or w whereas the CG w

remain in the same place (assuming no bilge

water), the CB will move to one side and a right lever is generated. As the boat continues to hee lever will increase to a maximum and then start diminishing until the CB is once again on the same vertical line as the CG.

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At this point the righting lever is again zero but unlike when upright, the boat will tend to invert if its heel angle continues to increase. This point is called the Angle of Vanishing Stability

(AVS). Once heeled past its AVS the GZ will become negative and an inverting lever rather than righting lever. Unless affected by some outside force, the boat will continue to 180 degrees of heel until the CG and CB are once again on the same vertical line and the boat is stable althoug now upside down. The diagram above shows a GZ curve for a typical monohull ballasted sailing yacht.

h

righting moment curve as required for the assessment in BS EN ISO 12217-1, for a given boat

ngle of Vanishing Stability (AVS) (Mandatory for Category A & B, optional for C & D) r

ategory A boat limits are a minimum mass of 3.0 tonnes and an AVS greater than (130 – (2 x

ategory B boat limits are a minimum mass of 1.5 tonnes and an AVS greater than (130 – (5 x

dditionally when this option is used Category C boats must have an AVS greater than 90º and A

is diagrammatically the same as it’s GZ. The only difference is that the vertical axis is a moment i.e. the GZ lever multiplied by the boat mass, rather than just the GZ lever.

A

For yachts one of the most easily seen and meaningful aspects of a GZ curve is the AVS. The angle of vanishing stability (i.e. the angle at which the ri ghting moment is zero) must be greate than a function based on displacement and a minimum value.

C

mass)) but always equal to or greater than 100º. C

mass)) but always equal to or greater than 95º. A

Category D boats an AVS greater than 75º.

ISO 12217 Required Mass & AVS - Cat A & B

0 5 10 15 20 80 90 100 110 120 130 140 150 AVS - degrees M a s s - t o n n e s Category A Category B

iagrammatically this means an RCD Category A boat needs to be to the right of and above the

tability Index (STIX) (Mandatory for Category A & B, optional for C & D)

The ‘norm’ ta

e. D

blue line of the above chart and an RCD Category B boat to the right and above the red line. S

STIX works by taking a base size factor which is adjusted by 7 modifying factors.

value for each modifying factor is 1 and each has absolute maximum and minimum limits. If da for one or more of the modifying factors is not available when calculating a STIX, the minimum limit for that factor would be used. For example four of the modifying factors require righting moment data. If this was not available then a STIX can still be calculated but the result would reflect the lack of righting moment data and the result tend to the cautious end of the STIX scal

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STIX Factors

1 Dynamic Stability

Factor

This factor represents the inherent righting energy to be overcome before a stability incident occurs.

2 Inversion Recovery

Factor

This factor represents the ability to recover unaided after an inversion.

3 Knockdown Recovery

Factor

This factor represents the ability of a boat to spill water out of the sails and hence recover after being knocked down.

4 Displacement Length

Factor

This factor accounts for the favourable effect of heavier displacement on a given length increasing the resistance to capsize.

5 Beam Displacement

Factor

This factor accounts for the increased venerability to capsize in beam seas of boats with appreciable

topside flare, and increased beam in relation to displacement.

6 Wind Moment Factor

Equals 1.0 for boats with downflooding angle greater than 90 degrees. For all other boats, this factor

represents the risk of downflooding due to a gust of wind heeling an unreefed boat.

7 Downflooding Factor This factor represents the risk of downflooding in a

knockdown. Downflooding Height Measurement & Assessment

Most options address the risk of downflooding which is the risk of water entering non-draining parts of a boat. The size and position of openings in the hull and their height, or in an open boat, the gunwale height above the water level must be greater than given limits. Engine exhausts, discharges connected to watertight systems (bilge outlet for example) and openings that are

provided with a watertight means of closure are not considered. The companionway is always to be considered open however watertight it may be. The full procedure for measurement is detailed in the standard and involves measuring the height of openings above the loaded waterline with

the boat at the Loaded Displacement M ass (m_LDC).

BS EN ISO 12217-2 gives tables with the required downflooding heights depending on the Design Category and length of the craft, it the craft does not meet these requirements using the more detailed calculations provided in Annex A (Full method for required downflooding height) may demonstrate compliance with the standard.

Downflooding Angle

This requirement is to show that there is sufficient margin of heel angle before significant

quantities of water can enter the boat. A simply method of calculating this is provided in Annex B (Methods for calculating downflooding angle), similarly to the downflooding height if this method does not show compliance with the requirements practical testing or computer simulation may provide an alternative method.

Knockdown Recovery Test (Category C & D only)

As an alternative to the STIX calculation this is a simple test shows that a boat with crew, will recover from a knockdown with sufficient speed to minimise the risk of swamping and sinking. The masthead is hauled down so that it touches the water before being released. The boat may downflood while being hauled over but it must recover to a position where it can still support the maximum load and be bailed out.

RCD Workshop Manual

RECREATIONAL CRAFT

RECREATIONAL CRAFT

DIRECTIVE

DIRECTIVE

WORKSHOP MANUAL

WORKSHOP MANUAL

2004

2004

CONTENTS

CONTENTS

CONTENTS

CONTENTS

Foreword

.

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)

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(

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