The mainsail sheet starts on a bridle attached to the mainsail sheet attachment points on the aft transom, or a split tail mainsheet is attached to these points. 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 mainsail boom. It then goes to a block mounted adjacent to the centre of the thwart. , then back to a second block mounted near the centre of the mainsail boom, then back down to a second block mounted adjacent to the centre of the thwart. Purchase is about 2:1
This system uses 5 blocks which is the maximum number permitted under the rules. I'm not aware of anyone using this on a Mirror, but it is a legal possibility. It's sometimes used on Flying Fifteens (hence the photos). It will have all the advantages of the other split tail systems, allowing 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, but giving the same purchase as the original system. A split tail mainsheet allows the boom to be brought closer to the centre line with less load on the mainsail leech than with the bridle system. The length of the bridle determines how closely this system matches the split tail system. A bridle which is as long as possible without going "block to block" when sailing close hauled will match a split tail mainsheet. There will be no need for a gybing strop as the falls of the mainsheet can be used to pull the boom directly when gybing.
- 2 mainsail sheet attachment points on the aft transom
- 1 split tail mainsheet (length undetermined at present)
- 1 single block mounted near the end of the main boom
- 2 single blocks or a double 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
- 2 single blocks (one 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.
- Methods to adjust the length of the bridle