Diagnosing a bad-looking main

[Sloop John B]

Man, and I was thinking of bleaching the mildew spots out of my stashed main. I'll let the sun have a crack at it.

[normo]

Man, that is one ugly sail.

I suspect the boomkicker is causing the wrinkles because I have a boomkicker and it did the same thing to my sail. It can raise the boom higher than the design shape of the sail. This creates the wrinkles. When sailing close hauled in even moderate wind the main sheet tension will overcome the the boom kicker lifting force and the wrinkles will disappear if the luff and foot tensions are reasonably correct. The most foolproof way to verify this is to remove the boom kicker. An easier way would be to apply lots of vang, which should override the boom kicker lifting force, and observe whether this adjustment removes the wrinkles. Sailing off the wind with the boom out (little mainsheet tension) is where the boom kicker can really affect sail shape. In very light air it is helpful to let the boomkicker hold the boom up but not to the degree that creates a poor shape.


If the boomkicker is not the problem double check to see that the mast is reasonably straight. If you have more than a few inches of bend loosen the backstay some. Also make sure there is nothing preventing a full hoist of the main. Next hoist the main and observe the luff. Continue to tighten the halyard until there are no wrinkles at the luff. Next tighten the foot of the sail with your outhaul adjustment. Observe the sail as you are doing this. The outhaul affects the flatness of the lower third of the sail and you should observe the sail getting flatter as you apply more tension on the outhaul. These two adjustments should get rid of most if not all of the wrinkles.

I'm not a big fan of the boomkicker. Have had it on, then off and now temporarily back on.

[mike]

Normo,

I really like the boomkicker... I didn't like having to deal with the topping lift! If it is indeed the cause of the problem, perhaps I need to modify how it is mounted (in other words, it could be applying too much upwards force to the boom, resulting in it being difficult to pull the boom down to where it needs to be with the vang). If I remember correctly, the mast-end of the boomkicker simply fits into the mast's slot, so it should be pretty easy to move it down a little without having to re-drill any holes.

--Mike

[Tom Spohn]

Leave the boomkicker on and make sure the vang is not tensioned. If you tension the vang when raising the sail the leach will tighten up and stop the luff from traveling to the top of the mast. A loose luff will cause wrinkles.

[dclark]

I can't imagine the boom kicker being installed so that there is so much upward pressure that you can't compensate for it with the vang. You could always try it the old fasion way - lift the boom until the boom kicker drops out of the slot and put the mast crutch back in. Now when you raise it do you have the same problem?

[normo]

Mike: I did not mean to imply you should remove the boomkicker permanently. Only to verify that it was causing the wrinkles and then reinstall it. As I said, the easier approach would be to just tighten the vang.

[Frank C]

Mike: I did not mean to imply you should remove the boomkicker permanently. Only to verify that it was causing the wrinkles and then reinstall it. As I said, the easier approach would be to just tighten the vang.

Precisely - you will rarely use the boomkicker alone, when under sail. It must be used in conjunction with the vang. For raising the main, you need just enough vang to counter the kicker - just make sure the boom is roughly perpendicular to the mast. Same rules apply for a rigid vang ... must use the vang to counter the upward spring tension, setting the boom so it's horizontal.

[Tom Root]

Has your bolt rope shrunk? If your mainsail retains wrinkles after you have adequate tension on the halyard and nothing else is holding it up, the reason you can't get the wrinkles out is because of the above. I've solved that problem by cutting the bolt rope. As far as I know the only reason for the bolt rope is to keep the sail in the mast slot altho I have slugs on mine. The bolt rope provides support for the slugs. Murv

Listen to wisdom here please!!! By the looks of what you have there, a simple razor blade knife, you can cut the bolt rope and your problem should go completely away! Murv told me of this method a long time ago. Look carefully at your bolt rope, if it is all wrinkled along the rope, that translates to a wrinkled sail!

Much simpler than it sounds, carefully severing the bolt rope about a foot from the tack of the sail, in BOTH of them, and tie off one end to something immobile. Of course do not cut into the sail area for obvious reasons. I used a tree on a grassy area to keep the sail relatively clean. One person puts all the stress on the sail as possible, use jerking motions to get more stretch, while the other person simply 'eases' or works the wrinkles out! I know it sounds crazy, but it really does work!

If doing it alone, I suppose you could attach both ends and push against it, while working them out also!

As Murv says, the bolt rope is there for support, but not something that can be adversely affected by severing it! I did a sail once that had 25 years on it, and it gave that sail new life, and I was able to get 12" on the foot, and 14" on the leech! That's substantial folks! ALL my wrinkles dissapeared along with a substantial 'Belly' in the sail. Now if only it was this easy for my belly!

If you want, you can easily thread a new piece of rope in the gap now caused. It is not really neccasary though!

This happens because all bolt ropes are made of cotton, it DOES shrink! It is beyond me why the bolt rope is sewn at either end of it, except that people end up buying new sails!

Tell ya what, if you don't want to do this and anyone who thinks their sail is a gonner, donate it to me....I'll put it to good use!

If anyone tries this, and has posative results, please post it here!

[Tom Spohn]

Halyard not tight enough and most likely the bolt rope has shrunk. The mac sail is put together with the bolt rope stitched into the sail at the bottom. When you are using slides the stitching can be carefully cut which will add from a few inches to 5 or 6 inches to the luff, depending on how old the sail is.