Getting good tension on the luff of the jib is important for sailing to windward. If there is no tension on the luff of the sail, the sail will sag to leeward, the boat will be stuck on a close reach, and tacking to windward will be slow and inefficient. At first I used the standard Wharram approach for getting tension on the luff which was to set a purchase from the sail tack to the forestay bridle and then back to a cleat on the beam. The only problem with this method is that the downhaul tension is also pulling the forestay back towards the front beam and changing the shape of the foretriangle. A further complication is that when the downhaul is rigged this way, it is tensioning the whole rig as well as the luff of the sail, and it is difficult to get everything really tight.
I am now using a system that separates these two jobs (see above). I have a 6:1 purchase tensioning the forestay (and thus the whole rig). I then use a separate 4:1 purchase just to tension the luff of the sail. By first tensioning the rig with the 6:1, I find that much less tension is required to shape the luff of the jib with the 4:1 purchase. With the 6:1 purchase, I can get the whole rig very tight for going to weather, or loosen it off for sailing off the wind. When sailing to weather in a strong breeze, a flat sail is needed with lots of rig tension. When sailing to weather in a light breeze, or when sailing off the wind, a more rounded sail from a looser rig is faster.
Update: OK, so it works, but is very fiddly. Even for a fiddler like me it became too much work. After a couple of years and many miles, I have changed to a conventional turnbuckle forestay tensioner, and use the 6:1 tackle for the jib downhaul. I have the jib fairly tight on the turnbuckle for average sailing conditions, and can crank down with the jib downhaul when the wind gets up.
I am now using a system that separates these two jobs (see above). I have a 6:1 purchase tensioning the forestay (and thus the whole rig). I then use a separate 4:1 purchase just to tension the luff of the sail. By first tensioning the rig with the 6:1, I find that much less tension is required to shape the luff of the jib with the 4:1 purchase. With the 6:1 purchase, I can get the whole rig very tight for going to weather, or loosen it off for sailing off the wind. When sailing to weather in a strong breeze, a flat sail is needed with lots of rig tension. When sailing to weather in a light breeze, or when sailing off the wind, a more rounded sail from a looser rig is faster.
Update: OK, so it works, but is very fiddly. Even for a fiddler like me it became too much work. After a couple of years and many miles, I have changed to a conventional turnbuckle forestay tensioner, and use the 6:1 tackle for the jib downhaul. I have the jib fairly tight on the turnbuckle for average sailing conditions, and can crank down with the jib downhaul when the wind gets up.
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That's an interesting setup you have. I don't think I've ever seen a forestay setup with blocks. I can understand the good of adjustable tension, but the hassle, cost and extra wind resistance would make me think a simple turnbuckle setup would me my choice. But having said that, if it works for you, congrats and I'm still in envy as I'm only sailing a ugly red chair:(
ReplyDeleteHi mgtdOcean,
DeleteSeveral dinghies are rigged this way and many keel boats have a backstay tensioning system that is similar (but on the backstay). The downside to a turnbuckle is that it is hard to adjust - this way you can adjust the rig tension on the fly. True about windage, but these are small blocks (3/4 inch sheeves).