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How to Upgrade the Sails on Your Multihull Modern design and fabric can really add to you by Brian Hancock multihulls sailing performance MULTIHULLS, BY THEIR VERY NATURE ARE A cruiser’s cruising boat. They are spacious, they don’t tip (much), they have a shallow draft and they are relatively fast. What’s not to like? It’s not surprising then how cutting-edge multihulls have become when it comes to innovation and their embrace of new technology, especially when it comes to sails. The first experience most multihull sailors have with sails are the standard crosscut Dacron sails that come with most production multihulls. They may be practical, but they are not very exciting and cheap construction and price take precedent over durability and performance. Usually the main is pinhead, meaning that there is an acute angle at the head of the sail and it does not incorporate a large roach or, as is increasingly popular, a square or a round head. Same too with headsails. They are usually unimaginative triangular sails there to suffice the requirements of a new owner being sold a boat. Multihulls are unique in that they are rigged in a tri-pod configuration, that is there is a headstay and two shrouds. The shrouds are attached as far outboard as possible, and aft of the mast so that there is no need for conventional spreaders. The tri-pod rig configuration supports the mast. This configuration has one big advantage and one, well not so great drawback. With just three pieces of 16 Multihulls Today • winter 2022
rigging supporting the mast there is no need for a backstay meaning that you can create just about any kind of mainsail that you like. There is no backstay to obstruct things when you need to tack. The drawback, however, is that because the shrouds are so far outboard you can’t have any kind of overlapping headsail. This is not really a bad thing because most multihulls are mainsail driven, meaning that the principal sail is the main and the headsail is there to provide a little extra sail area and to provide a bit of ‘slot effect’ when sailing to windward.
MAINSAILS
So, let’s see what we can do with the main. You can add as much roach as you like. This increases sail area while still having a fairly manageable sail. You can, if you like, make the sail square-headed, meaning that the top of the sail, rather than being pinhead, is square, or at a right angle to the mast. This provides an overall better sail profile but it comes with a couple of issues. One of the issues is the compression load on the “gaff” batten, the one that is angled to support the square head. Because of it’s configuration the “gaff” batten has to deal with much more compression than the other battens but this can be managed with a sturdy car on the inboard end, preferably one that runs on some kind of bearing system, either balls or rollers.
