11.2.2.2 — Multi-hulls Regeling veiligheid zeeschepen
Multi-hulls
.1 Curves of statical stability in both roll and pitch should be prepared for at least the Loaded Arrival with 10% consumables. The VCG should be obtained by one of the three methods listed below:
.1 inclining of complete craft in air on load cells, the VCG being calculated from the moments generated by the measured forces; or
.2 separate determination of weights of hull and rig (comprising masts and all running and standing rigging), and subsequent calculation assuming that the hull VCG is 75% of the hull depth above the bottom of the canoe body, and that the VCG of the rig is at half the length of the mast (or a weighted mean of the lengths of more than one mast); or
.3 a detailed calculation of the weight and CG position of all components of the vessel, plus a 15% margin of the resulting VCG height above the underside of canoe body.
.2 If naval architecture software is used to obtain a curve of pitch restoring moments, then the trim angle must be found for a series of longitudinal centre of gravity (LCG) positions forward of that necessary for the Design Waterline. The curve can then be derived as follows:
GZ in pitch = CG’ x cos (trim angle)
trim angle = tan
where: CG’= shift of
LCG forward of that required for design trim, measured parallel to baseline
TFP= draught at forward perpendicular
TAP= draught at aft perpendicular
LBP= length between perpendiculars
Approximations to maximum roll or pitch moments are not acceptable.
.3 Data should be provided to the user showing the maximum advised mean apparent wind speed appropriate to each combination of sails, such wind speeds being calculated as the lesser of the following:
or
where
v W = maximum advised apparent wind speed (knots)
LMR = maximum restoring moment in roll (N.m)
LMP = limiting restoring moment in pitch (N.m), defined as the pitch restoring moment at the least angle of the following:
a) angle of maximum pitch restoring moment, or
b) angle at which foredeck is immersed
c) 10° from design trim
A’ S = area of sails set including mast and boom (square metres)
h = height of combined centre of effort of sails and spars above the waterline φR= heel angle at maximum roll righting moment (in conjunction with LMR)
φP= limiting pitch angle used when calculating LMP (in conjunction with LMP)
A D = plan area of the hulls and deck (square metres)
b = distance from centroid of ADto the centreline of the leeward hull This data should be accompanied by the note:
In following winds, the tabulated safe wind speed for each sail combination should be reduced by the boat speed.
.4 If the maximum safe wind speed under full fore-and-aft sail is less than 27 knots, it should be demonstrated by calculation using annex D of ISO 12217-2 (2002) that, when inverted and/or fully flooded, the volume of buoyancy, expressed in cubic metres (m3 ), in the hull, fittings and
equipment is greater than:
1.2 x (fully loaded mass in tonnes)
thus ensuring that it is sufficient to support the mass of the fully loaded vessel by a margin. Allowance for trapped bubbles of air (apart from dedicated air tanks and watertight compartments) should not be included.
.5 The maximum safe wind speed with no sails set calculated in accordance with .3 above should exceed 36 knots. For Short Range Yachts this wind speed should exceed 32 knots.
.6 Trimarans used for unrestricted operations should have sidehulls each having a total buoyant volume of at least 150% of the displacement volume in the fully loaded condition.
.7 The stability information booklet should include information and guidance on:
.1 the stability hazards to which these craft are vulnerable, including the risk of capsize in roll and/or pitch;
.2 the importance of complying with the maximum advised apparent wind speed information supplied;
.3 the need to reduce the tabulated safe wind speeds by the vessel speed in following winds;
.4 the choice of sails to be set with respect to the prevailing wind strength, relative wind direction, and sea state;
.5 the precautions to be taken when altering course from a following to a beam wind.
.8 In vessels required to demonstrate the ability to float after inversion (according to .3 above), an emergency escape hatch should be fitted to each main inhabited watertight compartment such that it is above both upright and inverted waterlines.
- Regeling
- Regeling veiligheid zeeschepen
- Soort
- Ministeriële regeling
- Geldend vanaf
- 01-07-2026
- BWB-id
- BWBR0017728
- Versie
- 2026-07-01_0