11.9.2 Vessels without external ballast keels
Clasification Society 2024 - Version 9.40
Statutory Documents - MCA Publications - MGN 280 - Small Vessels in Commercial Use for Sport or Pleasure, Workboats and Pilot Boats - Alternative Construction Standards - 11 Intact Stability - 11.9 Sailing Monohull Vessels Complying with Section 11.1.1.3 - 11.9.2 Vessels without external ballast keels

11.9.2 Vessels without external ballast keels

Parent topic: 11.9 Sailing Monohull Vessels Complying with Section 11.1.1.3

Method 1

  .1 The centre of gravity (KG) of a vessel should be established by an inclining experiment of statical stability (GZ curves) for the loaded departure with 100% consumables and loaded arrival 10% consumables, should be produced.

Note 1. The above conditions may include a margin for growth up to 5% of the lightweight, at the discretion of the Certifying Authority, with the VCG positioned at the upper deck amidships.

Note 2. Buoyant structures intended to increase the range of positive stability should not be provided by fixtures to either a mast, rigging, or superstructure.

Note 3. For standard production series built vessels, the statical stability (GZ) may be derived from an inclining experiment conducted on another vessel of the series, subject to corrections for differences in outfit, to the satisfaction of the Certifying Authority.

  .2 Permitted area of operation

The permitted area of operation is dependent upon a vessel's range of stability as indicated in the table in Section 11.9.5. (The range of stability is to at least 90° in all cases)

  .3 For vessels operating in Area Category 6, it may be demonstrated by test or calculation, that an open sailing boat when fully swamped is capable of supporting its full outfit of equipment and the total number of persons for which it is to be certificated. Sailing dinghies (small non-decked boats generally in the range of 2.5 to 6 metres in length which are not mechanically propelled) and small un-ballasted sailing dayboats are to be capable of being righted by their crew after inversion.

Method 2

  .1 By the full application verified or performed by a Certifying Authority as required, of ISO12217 Part 2 'Small craft - Stability and buoyancy assessment and categorisation - Sailing boats of hull length greater than or equal to 6 metres', in accordance with Section 11.9.5. Vessels under 6 metres in length may not be considered by this method.

  .2 The permitted area of operation is dependent upon a vessel's assigned Design Category as indicated in the table in Section 11.9.5.

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