Trimaran handling

[longjonsilver]

i find my Cross 24 tri (with the cabin and LAR keel removed, and a big cockpit and daggerboard installed) tends in a puff (while beating) to first heel over, then blow the bow off, then accelerate allowing me to resume my course. Is this normal trimaran handling? Any suggestions for me?

[catsketcher]

I reckon your new dagger board is too small and too far aft. What I think is happening is that the extra sideforce from a gust acts forward of the CLR and blows the bow away. As the boat speeds up a little lee helm along with increased speed brings her up again. I would suggest making a larger dagger board that can be pivoted forward a little. Many multi boards are too small imho. Going large on foils may slow down a race boat but always improves handling

[Cavalier MK2]

I think Phil is on the right track but I'd play with the mast rake first which will be easier than the board. Raking aft should add some weather helm to counter the lee helm you have now.

[longjonsilver]

Thanks for all your replies and ideas. i actually think shez well balanced. A slight bit of weather helm on reaches and upwind. The board apparently is built to Cross' plans (i have the plans). i trim to the apparent wind and sail up in the puffs and off in the luffs. When i have "too" much power in the sails i gain to windward, and when i have too little i gain speed by falling off slightly.

Ideas?

[Cavalier MK2]

Well then you should play with the sheeting angles on the jib. You want to try to flatten it more, take out some camber. If you have tracks try moving the block aft. One thing to remember is that while your board may be according to plan I don't believe your rig is? You want your C of E of the sail plan in the same place as the stock rig.

[longjonsilver]

Originally Posted by Cavalier MK2

Well then you should play with the sheeting angles on the jib. You want to try to flatten it more, take out some camber. If you have tracks try moving the block aft. One thing to remember is that while your board may be according to plan I don't believe your rig is? You want your C of E of the sail plan in the same place as the stock rig.

Jib is on club. i can however tighten the outhaul on the club. The main is a square top and the foot of the sail is about 1 ft shorter than the boom, so i assume that the CE is farther forward than stock. Next year i will try to rake the mast aft. If i remember correctly the PO said that she sails better with the mast raked aft.

i plan on adding a short cable to the tack of the jib to raise it. That will help the club clear the tabernacle and me to see forward better.

[Kettlewell]

Keep in mind that with multis it is usually better to stay off the wind a bit more and keep the speed up, particularly when there is a chop. With our cruising cat we found it was better to not sheet everything in hard like we would on a mono, but to ease off just a bit, sail a lower angle, yet get there faster due to the much higher speed a few degrees off the wind can mean.

[Don C L]

How old/used are your sails?

[longjonsilver]

Originally Posted by Don C L

How old/used are your sails?

About two years, fully battened, square top main, carbon fiber

[Ryan]

I've got a Corsair F-24 trimaran with a daggerboard. Upwind, there's a little helm just as you might expect in a monohull. When pressed, the helm doesn't increase. At some point well after I should have de-powered and the leeward float is mostly submerged, the rudder will loose grip and the boat will round up into the wind.

I'm not sure I'd be comfortable with lee helm sailing upwind in high winds.

Downwind, the helm is very neutral, especially when planing.