the bottom of my jib is constantly flapping... how can i fix this? also what are the tracks that can move the jib blocks fore and aft for? when would i want the blocks further forward and when would I want them further back? thank you in advance for your help.



edited by: Ecker786, Jun 22, 2009 - 11:36 PM

if the bottom of your jib is flapping but the back of the jib is not it sounds like your jib blocks are pulling too vertically on the jib tack

ie if you can move the jib blocks back there will be a more horizontal vector in their pull and the jib bottom should tighten up

you generally work this out by having 2 sets of telltales on your jib

a high set and a low set

if the low sets breaks from streaming before the high set the bottom is too loose and you need to move the jib blocks back to balance the tensions

if the high set breaks from streaming before the low set you need to move the blocks further forward

not sure on the hobie18 but many hobie's have a 4 position plate at the jib tack where you attach the jib sheet

experiment on different positions to see if that helps balance the sail

Also.... with the blocks not attached to your jib clew (tack) pull down and aft... you should be able to feel/see the position where there is equal pull from the foot and leach. this is close to where you want your jib sheet/block to be.

The fore / aft adjusters are also a good way to depower in heavy air. by moving them back (past where there is equal pull on the foot/leach) you can open the top of the jib and spill air off (depower) in heavy air. the opposite (forward in light air) only works a little as you will lose shape in light air and lose efficacy.

I thought you would bite at that one Andrew. I couldn't help it. The pilot in me just wanted out.

Sails are not unlike an air foil or wing. The theory applies to air flow as well. You know the Lo pressure Hi pressure issue. Sail tension changes this property as the sail shape changes. Don't want to get all technical. Keep it simple.

Like I was saying trial and error will work this out.

UFgator

I thought you would bite at that one Andrew. I couldn't help it. The pilot in me just wanted out.

Like I was saying trial and error will work this out.

ummmm... i think i have seen this post before! :)

Ok sounds good ill experiment and see if i can figure it out. Thanks guys.