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Posts Tagged ‘sail tuning’

Over the weekend I was asked for my thoughts on windy weather footy sailing by a group in Florida. I thought more people might be interested in a few ideas of how to handle strong wind conditions and  I can perhaps expand here on how I answered them.

The first thing to say is that the wind can get too strong for any size rig, even the tiny ‘B-rig’ as specified by the footy rules will simply be too big for extreme conditions. So these thoughts will assume that although the wind is strong it is not enough to change down in sail size. So we will look at how to tune the sails to manage the conditions better. Also this discussion assumes you are using a sloop rig with a main sail and a jib sail. 

Your main tool to combat strong wind conditions is sail twist. Allowing the sails to twist away from the wind towards the top of the sail will dump more air from the upper parts of the sails but maintain a good drive from the sails. The mainsail twist is controlled by the kicking strap or vang fitted from the main boom to the mast. The jib sail twist is controled by the ‘topping lift’ which is the line running from the rear of the jib boom up to a point on the mast or mast head where the forestay is attached.

By loosening the kicking strap the main boom will be allowed to rise and in doing so will control the amount of twist in the main sail. Likewise tightenning the topping lift will raise the rear end of the jib boom (you may have to ease the forestay tension a little) imparting twist in the jib. Set the jib twist to echo the shape you see in the mainsail, look from the rear with the wind filling the sails to see this.

Pond Sprite showing sail twist in main and jib

Pond Sprite showing sail twist in main and jib

The balance of the boat in high winds will tend to gain more weather helm, in landlubber talk that means that the boat will turn up harder into the wind when you are close hauled sailing close to the wind. Using more twist in the main than the jib and flattenning the foot of the main more than the jib are ways to control this ‘luffing’ into wind. Also you can move the jib pivot further forward on the bowsprit if you have one to combat weather helm in strong winds.

Sail foot curve is generally reduced too in strong winds. Set the outhauls (rear bottom corner sail attachment on booms) to allow about a 1/2″ curve from the sail edge to the boom at the mid point.

For a strong wind racing day I like to have a rig (about the size of the original Kittiwake I rig) which is set up with the ability to add a lot of twist in the main and the jib. The rig can then be detuned to be almost like a B rig and tightenned up considerably if the wind does ease a little. Then if the wind does get even stronger you can still change down to a rules size B rig.

Victor V12 with nicely set twist in a blow

Victor V12 with nicely set twist in a blow

Those windy days can be enjoyed, not avoided with the right set up and tuning, give it a try… footys on a B rig can handle just about anything, just make sure they are watertight! And unsinkable is a plus!

Graham

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Yesterday morning saw just myself and Mark at the SAMYC lake in Kohler, WI. Winds were light and quite variable so we decided not to race with two regulars missing. It was one of those pleasant warm days when messing about with boats is the perfect pastime. Now Mark’s Kittiwake hasn’t been the fastest in our fleet and I am sure that it is not the skipper so I took the opportunity to watch it carefully and try to understand why.

After a while we swapped boats so that Mark could try out my Pond Sprite and I could get my hands on his Kittiwake… trusting soul that he is. What was obvious was that his boat just would not settle on a course and maintain drive. Not that it was wandering like it was badly out of balance, just that it would keep popping upright and losing drive for no obvious reason. I put some extra curve in the foot of each sail to suit the light conditions and tried to bring it back to the starting point I discuss on the ‘tuning your sails’ section here. That had little effect on the problem. It seemed that the mainsail was unwilling to swing very easily and the jib didn’t respond well either to light puffs. I checked the mast rings to see that the mainsail cleared the mast when pulled back, it did. Main luff tension was ok too, just enough to hold the luff straight. The jib seemed to swing easily enough in the hand but it didn’t have a balance weight at the front so I thought that was why it was reluctant to go wing on wing downwind.

The overall effect was that the sails were stuck in the middle and didn’t respond to the light puffs which saw Mark and the Pond Sprite sailing happily by me. Then after a half hour or so I found it, the Jib swivel was standing nice and straight due to a pretty tight forestay, I slackenned that a little and saw the mast relax. The jib sail luff tensioner was also tight so I slackenned that off so it was just enough to hold the jib luff (front edge) straight. Everything freed up at once, the mast bend was clearly causing the mainsail to stick.

Back on the water the Kittiwake was now much more responsive and able to maintain drive. I added some jib leech line tension to twist the jib off a little so as to soften the luffs in the occasional gusts and then she was sailing well. A footy needs to be able to respond on it’s own to the slightest wind  speed or direction change and to do that both sails need to be able to move very freely. Even at the cost of a little forestay tension.

It was a fun morning, I hope that you got a little sailing in too.
Graham

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