[quote=sierracat]Wolfman, great info as usual.
[quote]So the boomless rig should tension correctly. So that sail will likely work for the intended use as long as you hook the mainsheet up to the forward or middle holes only. If you get behind the main beam you definitely wont be able to tension it with the mainsheet properly. [/quote]
On the most forward hole, as in the pic, the mainsheet is almost dead vertical, or perhaps just very slight rearward pull. It does weird things to the sail and doesn't look right at all. Obviously the boat will still sail, but I think it would drive me crazy.
[quote]The only thing that really worries me a bit is that there may not be enough room under the sail to get enough tension on the mainsheet.[/quote]
[quote]s there any room at the top of the mast to raise the sail a few more inches?[/quote]
I didn't pay a lot of attention to way up there unfortunately (the test rigging was fairly hurried, not only because it was 28 degrees out). I'm pretty sure though that the sail was raised to the max.
[quote]Also if you have any rake in the mast try and straighten it out.[/quote]
We guessed the hole position on the 10 hole chainplates, pretty much the middle, and found the stays too loose and the mast too vertical. So we went lower in the side stays, but didn't mess around too much since there were other things to test out (I was just happy the stays seemed to belong with this rig and were close enough). We need more tension still I feel, and more aft rake, so next time I'll put the side stays on the bottom holes and the bridle connections on whichever holes needed to get it tight. When making my new v-strap and cutting the beams etc. I deliberately wanted the mast rod and ball to only protrude from the main beam the minimum distance needed for stepping and rotation clearance, plus a bit. I ended up with about one inch of exposed threaded rod between the top nut and the bottom of the nylon ball (about right according to my veteran nacra source). Anyway. I see rather a lot of pics of mast rods extending waaaaaaaay out of the beam - several inches of exposed rod - mostly because the replacement rods were made longer than the originals to cater for all models, bigger and smaller. Anyway, in hindsight my nice low profile mast ball may have put some extra slack in the stays with the decreased height. Hopefully I can still soak this up and get the right rake. If not…. damn.
I digress. In the first photo, where you don't see much clearance, the main sheet is cranked pretty tight. I was seeing what would happen with the foot tension, and also checking out the mast bend. I think I'll be ok with enough clearance, although you have me wondering if it'll be a squeeze to get under the sail when going about, especially with a boom!
As for your suggested options, # 2, 3 and 4 aren't an option financially. Besides not doing anything at all, I think making a boom would be the cheapest option, and not overly difficult. Especially if you send me some parts! (thanks! - lets talk more once I have a solid plan for this boom design).
[quote]#1, rig a boom to it. Not as hard as you might think. You can get a swivel from another old Nacra then its just a piece of aluminum tube (2" dia by 1/8" wall will do) a couple of cleats pad eyes and some dyneema rope to make the connections and a workable outhaul. I can send you most of the parts (except the mast connection) for the shipping cost if you can wait til spring. [/quote]
Leaning toward this. Not concerned at all with the process of fabricating it, but more so finding the right parts and getting the dimensions and mechanics of it working correctly together. I realize its a pretty simple part once it's in use, but I like to do things right. I have seen google search images of various nacra gooseneck parts, but no detailed pics of them fitted to a boat, so I really can't visualize the attachment between boom and mast properly. I would prefer to go off the mast, not the main beam, since I'll sail with a partner most of the time, I want as much clearance from the tramp up front as possible.
Someone suggested a strop/loop of line *around* the boom and through an eye on the clew plate, directing the pull straight to the sail and not through the boom. This would allow for a lighter boom construction. I like it. But would I have just one loop, and pick one of the three holes to thread through, are have three loops (one through each hole) to maintain adjustability in the pull direction? I think I can almost answer my own question (one loop?) and that the outhaul will take the place of changing the sail shape (e.g. flattening it out) instead of changing the pull point or using a clew traveller (that's another thread 8-) )
And the mast rotation wishbone - currently mounted facing forward (boomless). Would I need to remove and face aft with a boom? I basing this question on stuff I've read here previously. e.g. "All boomless rigs you want to induce rotation, especially off the wind. On rigs with booms the rotation is induced due to compression from the mainsheet on the boom, so you want to limit rotation"
I hope my questions don't seem to daft. I'm rebuilding a boat I've never sailed, and my last significant cat experience was 15 years ago![/quote]
