How do I correct a lee helm?

samsciacca · #1 (**permalink**) 08-15-2007

I just bought an AMF Puffer (12.5' sloop rigged) and found out it has quite a lee helm. I've loosened up the forestay (there's no backstay), and tried trimming the jib tight and easing the main outhaul to get more power aft, but this still has not worked. Centerboard appears to be the original and I have a strap to keep it securely down. The lee helm does not seem to change in light or fresh wind. Any suggestions?
Sam

SanderO · #2 (**permalink**) 08-15-2007

You have to move the center of effort forward I believe.

jef
sv shiva

christyleigh · #3 (**permalink**) 08-15-2007

There may be other factors but even though loosening the forstay decreases your pointing ability it powers up the jib probably giving you some lee helm.

otaga05 · #4 (**permalink**) 08-15-2007

You want to move the center of effort aft and the center of resistance forward.

Sail without the jib, like a catboat, or reduce the size of the jib.

Is it possible to move the tack of the sail up the forestay a little so that the foot of the jib is a few inches off the foredeck and the jib is a little further back and up as a whole? This will both make the jib less efficient and move its center of effort aft.

Don't over tighten the main halyard.

The centerboard is not symmetric. Install it so that the longer edge is forward.

try to keep weight forward as much as possible. you might want to consider removing the 20 hp engine from the transom.....

Sit low and keep the boat heeled.

samsciacca · #5 (**permalink**) 08-15-2007

Otaga05

Great suggestions....makes a lot of sense. I can absolutely move the tack of the jib up a bit. With no rigging directions to go by, I had been attaching the jib tack very close to the forestay base. Next time out I'll put a short piece of line between the tack and the forestay base which will allow me to adjust the distance the tack moves up the forestay.

On the centerboard, I had been putting the short edge forward. I'll reverse this as well to see what effect it has.

On the main halyard, one thing that I'm wondering about: the design allows for boom (and the foot of the main) to travel up and down about 18 inches. I have been raising the main to the top of the mast and then tensioning the downhaul. Do you think that raising the main less than the full height would help?

PS: If I remove the outboard motor, it will make it much more difficult to get a skier up, so I'd prefer not to do that except as a last resort

sailingdog · #6 (**permalink**) 08-15-2007

Another possibility is to rake the mast aft a bit. Does the mast step have any ability to adjust its position.

samsciacca · #7 (**permalink**) 08-16-2007

Sailing Dog

Not without a lot of boat modifications. There is no backstay on this design. The shrouds are set aft of the mast to provide the back tension, but they are not adjustable. The mast step provides no adjustment to lean the mast off vertical.

ianhlnd · #8 (**permalink**) 08-18-2007

If you can't make the adjustments suggested above, decrease the jib size, or increase the main size. Usually, if not critical, bringing in the mainsheet will balance and get you more weather helm to offset the lea helm. This may also cause more heeling. Practice with your boat and you'll figure it out.

sailingdog · #9 (**permalink**) 08-19-2007

Get a longer boom and mainsail.

Will shift COE aft... and help remove lee helm.

RichH · #10 (**permalink**) 08-20-2007

With a loose forestay what you probably have is not lee helm but SLIP to leeward. With the boat slipping off to leeward (and also not able to 'point' to weather very well) you will also feel a bit a helm pressure like the boat is having a 'weather helm' imbalance in the tiller but is still behaving like leehelm.
Try running the forestay tighter so that the jib (luff) more or less conforms to the shape that the sailmaker cut into it. Take the jib and lay it FLAT on the ground then notice the 'curve' that luff (leading edge) take --- when sailing (generally) the curve in the luff of a jib should be close to the curve when its laying FLAT on the ground .... you adjust this 'curve' (forestay sag) by adjusting the forestay tension (or more correctly by backstay tension in a boat that has a backstay). When sailing and with proper forestay tension the jib should be 'similiar' in shape as what you saw when the jib was laying FLAT on the ground.

A jib thats on a too-loose forestay will develop some severe draft/fullness problems .... a draft positon thats too far aft and also too full in the wrong section of the sail. .... a correct or tight forestay will usually correct all of this.

You can also do a websearch for "luff sag" and do a bit more or research on the matter.

hope this helps.