Hot Yacht – Part Three

by Paul Austin - Dallas, Texas - USA

The Hot Yacht sails quite well for a flat-bottomed skiff hull with a cutter rig.  But I noticed when it leans over and recovers, it recovers directly to windward.  And this halts its’ movement until it can fall off the wind again.  But it still comes around to windward.  So I realized the boat has a windward helm, and plenty of it.  This has become frustrating because my first model, Swirl, sailed perfectly.

So I consulted a sail design book, finding out my model had a center of effort too far aft of the hull’s center of buoyancy.  I thought about what I could change the least and reduce that weather helm somewhat.  I decided to enlarge the headsail, cut some of the keel off and extend the mainsail to forward of  the mast while I shortened the mast by two inches.

This worked pretty well, but not completely.  Here is the sail rig now.

 

 

The other adjustment was to let the mainsail out some but bring the headsail in tight, so that it is over the deck.  That enables the headsail to do more of the center of effort work, while the mainsail only pulls on certain headings.

But I’m wondering if the keel, being narrow of chord but deep, is not too far aft thus causing the trouble in the first place.

Next week I’m going to take the tape off the tall slender triangular section of the mainsail which lays on the boom.  I’ll make it a second headsail, closer to the forward headsail, to see how that works.

I’ve got video of the boat sailing, with a small camera facing the bow.

Part OnePart Two – Part Three

1 Comment

  1. If you helm is heavy, there’s two ways of dealing with it; move more sail area forward, increasing the “lead” or add additional lateral area under the boat aft, which does the same thing. Raking the mast is the usual choice for modest adjustments. Adding more jib, possibly with a longer sprit is an option, though you should check to see if you actually have “weather helm” or another issue, that can mimic this issue. The usual check on full size craft is to measure the amount of helm deflection on a close hauled course, in moderate wind strengths. It should be about 4 or 5 degrees of deflection. If less you’ll have issues in lighter winds and if more you need more lateral area aft or sail forward.

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