A Smaller Mainsail

[[e-mail]]

  I have been talking to Randy Smyth about the possibility of designing and building a smaller main for those really high wind days or when I want to go out solo in over 15 knots and not have to work my butt off.  One thing we realized is that it would most likely have to be a boomless main, because when you cut the foot short by a foot or so, you will mess up your boom sheeting angle.  I have been sailing a boomless Nacra 5.5 for some time and I liked it.  The boom is very low at the mast already and I told Randy I wouldn't mind having some more room to get across under there.  Pete Cogan has already built one but I have not seen it yet, WF has sailed with it.  If you are interested in getting one, contact me or Randy or Pete or WF or someone!  Now is the time for input as to design and size.  If we order in mass, there might even be a discount.  Thanks.  Tim Bohan

[Fred_Glaubke]

Tim,

I do like the idea of having a smaller main for occasional singlehanding or when the wind is blazing.  I di like the control that having a boom offers and would perfer that a boom be included in any consideration.  How would you control mast rotation with out a boom or major rigging changes (N 6.0 mast lever?).  Building a 16-17 sm main with boom and small roach/head would allow me to switch back and forth from big to small main without any modification to the rigging.  

[davidhertz]

Tim and Fred,

I spoke to W.F. yesterday about the design of the smaller sail that he has been testing.  He only had a moment, however he said that the Cogan small main looked great.  He was not sure about the exact sail area, but said it was between 16 and 17 square meters.  There was little roach and a smallish head.  The boom was still used, so the foot is similar in length to the standard main.

I agree that the mainsail should have a boom, so that minimal (no) rigging changes are necessary.  Also the sail is easier to depower with a boom.  

[[e-mail]]

   Randy is working on a way to attach the present mast rotator line to the clew area, so you could still control mast rotation.  As with my Nacra 5.5 boomless main, the tighter you sheet the flatter the bottom of the sail gets anyway, because the sheet is pulling back towards the rear beam.  You could add some sort of hanging clete to the clew shackle to ease or tighten the mast rotator.  I think his design would look more like an A cat sail, still go to the top of the mast, just skinny all the way down, still square topped, just shorter on the foot.  I would like to see a drawing of it first, though.  Tim

[Fred_Glaubke]

Tim,

You said something important, "the tighter you sheet the flatter the mainsail".  Well, unfortunately the inverse is true too!  When a gust hits and you ease the mainsail, the sail gets fuller right when you least want it to!

If boomless was better, then A-Cats would be boomless and they are not.  Let's stick with the boom and keep the rigging more simple.

[[e-mail]]

  Fred, maybe I'm doing something wrong but in a gust, I ease the traveler, not the mainsheet.  With a boom or without, if you ease the main, it will get fuller as you have said.  I also poke the nose up into the wind just a little if the hull starts to come up too much.  I think the A cats use a boom for the downwind work?  Maybe to get the main out as far as possible in light air.  I sailed my Nacra 5.5 in some pretty big wind and never had a problem without a boom, even in the gusts.  As far as keeping the rigging simple, boomless is more simple than boom on. (You also have more room for the crew to get under the sail in a tack or gybe)  You just put the main up and attach the mainsheet blocks, go sail.  I might even put on an S hook so I can just ease the mainsheet and unhook it on the way into the beach.  You can try it either way...that is, even on a boomless sail, you could run your boom and see how you like it.  For me this is a play sail, not for racing unless it is super windy, and then I don't think a boom is going to matter one way or the other, stricktly survival sailing going upwind  and probably not going to run the spinnaker downwind.   As it is now, the clew attach floats over the boom anyway, (there is a halyard ring around the boom, no hard attachment to it) the boom is just there to hold the outhaul line in place because the clew of the full size main is actually behind the mainsheet blocks.  The alternative would be to make a main with the full size foot, cut like a triangle straight to the mast tip.  Maybe this would work too, but that triangle shape creates alot more drag (especially the top 40% of the sail) than a more straight, glider wing type shape.  The goal here is max lift vs. drag.  Not max drag vs. lift.  If you are going to use the full length mast, you might as well have a sail up there that works in the top 40%.  Drag is never good, no matter what the wind.  Tim (I took two years of Aero Engineering and stayed at a Holiday Inn Express...)  

[Bill Vining]

Tim,
I would be interested in a smaller main. Boomless(loose footed) or mainsail with a boom, I would be interested in what the forum members decides is better. My thought is that this is a fun sail and used for really big wind, so simpler is better (less to break)

Hopefully there will be a concensus - although it doesnt look like it yet.

Any idea on the cost?

Thanks

Bill Vining