Help With Sail Trim

I have a question about sail trim... I was out this weekend 1-up in about 10mph winds and when going upwind, I was having trouble getting all the telltales to brake at the same time. When the uppers were streaming nice, the lowers were stalling. When the lowers were streaming the uppers were luffing.

If I understand correctly, that means I need more downhaul?

Thanks,

Good luck, that's been driving me crazy for as along as I've owned the boat.

From what I understand, the traveler effects your lower telltales and the main sheet effects your upper telltales. With the first scenario I would think traveling out until that back ones flow would work, but that doesn't make sense though if you're going upwind.

Maybe try to head upwind a little more and see if the back starts to flow, and then if the the top starts to luff, sheet in harder? Do you have telltales on the leech? How were they flowing?

I'm new to this as well, but these are just some of my thoughts.

Sounds like the bottom half of you main was too full. Did you play with your outhaul?

Did you try pulling it out to make the bottom half of the main flatter?

Provided you have tried the above. (sheet tension, downhaul, outhaul, mast rotation)
The middle of sail is where the highest percentage of power is.
So middle of the sail has to be correct first, my guess is 8 percent draft at 45 percent back for the middle (including mast)?

Coordinate the top & bottom telltales with the middle of the sail.
Try making the middle of the flatter or fuller.
Or try making the top flatter and bottom fuller,
or try making the top fuller and bottom flatter using different weight battens.
Basically, you are trying to change the angle of incidence of the sail up & at the mast. Sailmaker?

From looking at a lot of square top mains the top diagonal batten appears to always flatten the sail to lower the induced drag?
There are also threads on spreader rake and tension on how it affects mast bend may help.

Ringo,

I have telltales on the leech, but only at the top, they were flowing fine. According to what I've read, my sail had too much twist in it and I should have sheeted in harder. I was sheeted in as hard as I could, to the point that when I pulled on the mainsheet, the traveller would pull windward instead of the main sheeting in. Next time, I'll try a different angle so the traveller won't move.

Timbo,

I hadn't thought of that. I'll try tightening up my outhaul. I normally keep it loose in light wind like that.

sail7seas,

I was wondering if the battens might have something to do with it too.

I will try out all the suggestions this Saturday and report back.

Try looking at the Falcon Marine web site. They have a tuning guide that trys to explain sail shape as opposed to a cookie cutter setting guide.
Sounds like your mast is not set up to match your sail.

Also if you are pulling the traveler to weather , you need to look at splitting the tail of the traveler and tying off to each side of center line.

When it comes to 'tweaking' anything, I always start with the quickest/easiers stuff first...it don't get much easier than pulling the outhaul out a little bit and see what happens. Once you've gone all the way out with it, then start on the down haul.

But sail around for 10 minutes between changing settings, so you can see what effect your changes are having, and only change one thing at a time, ie. do NOT pull both the downhaul and outhaul, do one, sail around, looking up at the main, slowly head up until the telltale start to lift, and watch.

Try that a couple times, see what effect the change has made. Then then do the other change, repeat, etc.

Sounds to me like he needs more pre-bend in the mast.

Check out AHPC Support. You might find something here that will assist.

If you are using a main from a sloop set of sails, it is probably designed to work with a jib and is cut flatter on the bottom. What then happens is if you trim correctly for the top of the sail, the bottom stalls because there is no jib directing the air over the back of the main.

Some pics of the sail when setup...?