The mainsail sheet starts near the end of the boom, or the becket of a block attached near the end of the boom. It then goes around a single block attahced to a bridle attached to the mainsail sheet attachment points on the aft transom. It then goes around a single block near the end of the main boom, through a boom sleeve or constraining loop on the main boom to a block near the centre of the main boom. It then goes down to a block mounted adjacent to the centre of the thwart. Purchase is about 2.5:1
Widely regarded as the best system for helms not strong enough to cope with the previous system without the purchase. It allows the main boom to be brought closer to the centre line with less load on the mainsail leech than with the traditional aft mainsail sheet system. The length of the bridle determines how efficiently this system does this. A bridle which is as long as possible without going "block to block" when sailing close hauled is most efficient.
There is also a 2007 advise sheet on setting this system up.
Equipment list
- 2 mainsail sheet attachment points on the aft transom
- 1 normal mainsheet 8m long + 1 bridle
- 1 single block with becket mounted near the end of the main boom
- 1 single block mounted on the bridle
- 1 single block mounted near the centre of the main boom
- 1 boom sleeve or constraining loop mounted on the main boom between the blocks on the main boom
- 1 block (a ratchet block is permitted) mounted near the centre of the thwart.
Optional Equipment list
- A cleat may be associated with the block mounted near the centre of the thwart.
- A gybing strop
- Methods to adjust the length of the bridle
