SOLID MAST OR GUNTER

[wscherf]

More questions about my 16' daysailor rig. The designer (Paul Fisher) had no problem with solid rig or gunter. I told him gunter for convenience of smaller spars. Solid mast would be about 23' long.

Now I'm wondering about the performance characteristics of the two rigs. My common sense tells me that the solid mast with the sail running in a track would be more aerodynamically efficient than the gunter.

Not a racer, but do not want to pay too much of a performance penalty. Any thoughts?

[ishmael]

There are some good discussions of this in the archives, but the short answer is that a good gunter rig is not going to point quite as high as a good Bermudan. The ease of handling: shorter spars, quick sail reduction...more than make up for it in a small boat. IMO.

[J. Dillon]

What Ish said.

And the mast comes down some when you reef, reducing weight and windage aloft. Going to windward isn't the only point of sail.

Maybe Todd B. will come in on this one.

JD

[Todd Bradshaw]

I suppose the one-piece mast may perform better, though in average daysailing conditions it may be pretty hard to tell much difference. A couple of five second losses of concentration could easily wipe out any gain in performance offered by the difference in rigs.

I have a bit of a bias against taller gunter rigs, mostly because I detest trying to make sails for them. The fact that what functions as the mast is really two pieces with different flex characteristics, combined at a spot where they overlap which also has different flex characteristics than either section has by itself, drives me nuts. Add to this any stretch in the halyard which is holding the upper section up (which affects both the effective flex and the head angle of the sail) and you have too many variables for my taste.

When I build someone a gunter sail for such a system, I put them through the wringer. I have them assemble the spars and boom, strung together with lines, weight the boom and do a whole bunch of bend measurements. On small bendy-sparred rigs, I've even had them tension the spars on the floor, trace the shape of the loaded mast and send me the tracing before designing the sail. Even so, in the end, I have to guess about the actual in-use bend and build my best estimate into the luff curve. The only way to find out if I guessed right is to hang up the finished sail and see what happens. At that point, any serious modification to the shape would require drastic surgery.

This doesn't mean that you can't make a perfectly good gunter sail for such a boat (maybe just that I can't, or don't have the tolerance for it) but these things need to be addressed by anybody willing to take on the task if they intend to do it right. A mast that long for a boat that small is going to have a lot of flex whether one piece or two. I can certainly see the practical reasons that transporting the mast in two pieces would be handy, but it may make the sailshape considerably more unpredictable.