Section 4 Rig support

4.1.1 Assessment of rig support structures (e.g. mast step, chain plates, winch foundations and strong points) as outlined in this Section is part of the hull appraisal. The assessment is not part of the RIGGING or RIGGING* notations, but loads are to be considered in the design evaluation report of the TCF.

4.2.1 Sailing yacht mast and standing rigging loadings and their support structure require special consideration as follows:

• Efficient integration of the mast into the hull.
• Adequate hull and deck longitudinal structure to resist hull bending.
• Provision of adequate transverse structure in way of masts, chainplates, keels, skegs etc.
• Provision of adequate bottom structure to support the mast and dissipate the mast loadings.
• Local reinforcement in way of chainplates, forestay and backstay fittings, etc.
• The deck and beams are to be suitably strengthened in way of masts, coachroof/deckhouse ends, windlass, cleats, sheet winches, sheet tracks etc. Where a mast is stepped on the deck or coachroof/deckhouse, the structural arrangements will be specially considered.

4.2.2 Details of the designer's/Builder's calculated maximum loads on the mast heel and the breaking loads of all standing rigging are to be submitted with the main structural plans for appraisal.

4.3.1 The hull structure in way of the bowsprit is to be suitably reinforced with due account taken of the compressive loads along the bowsprit and bending moments due to rigging loads.

4.3.2  Details of the designer's/Builder's calculated maximum loads on the bowsprit and the breaking loads of all associated standing rigging are to be submitted with the main structural plans for appraisal.

4.4.1 Chainplates and other securing arrangements to take the loads of all standing rigging for masts and bowsprits, are to be of substantial construction and well integrated with the hull and/or deck supporting structure. They are to be of sufficient strength that, in the event of failure of the standing rigging, the watertight integrity of the hull is not impaired.

4.4.2 The breaking loads of all mast and bowsprit standing rigging, together with the actual loads imposed by the rigging, are to be submitted.

4.4.3 The minimum load to be applied to chainplates is the lesser of the breaking load or 2,5 times the maximum working load of the rigging. Each item of the supporting structure is to have a factor of safety applied as specified in Table 7.4.1 Factors of safety for rig support items.