Aramid

Family of mordern synthetic fibres, such as Kevlar. Woven or plaited, alone or mixed, these fibres are used for sails, ropes, equipment, and hulls.

Backstay

Running rigging at the rear of the boat which supports the mast and opposes the forestay at the front. The backstay can be single or double.

Batten

Strip of (wood or synthetic) thin and narrow material fed into a batten pocket in the sail to maintain the shape of the leech. 

Bolt rope

Rope stiched to the front (luff) of the sail to reinforce and prevent it deforming. The bolt rope supports the sailcloth otherwise loaded by wind over the sail.

Boom

The boom is a spar perpendicular to the mast which tensions the foot of the main sail. Other sails can be boomed( jib, staysail) makingtacking or downwind reaching easier without the need to pole out. 

Deck Hardware

All the equipment  (hatches, stancions, lifelines...) and fittings (winches, pulleys, shackles, cleats...) which make up the hardware for a yacht today. The supplier catalogues also include other ancillaries and security equipment.

Flex

Percentage of resistence lost after 60 flexions at 90°.

Flow

Irreversible deformation of a material under heavy constant load.

Foot

Lower edge of a sail between the tack ( forward corner) and the clew (where the sheets are attached).