Friday, February 13, 2009

Fine Tune Mainsheet for Old Boom

For 88 we were able to mount a fine tune internally, as our boom has a redesigned vang attachment and mainsheet headknocker. For older booms, a different solution is required due to the stainless attachment for the vang, and to work with the existing headknocker/trigger cleat that many teams favor.

Gary from 196 wanted to add a system to his boat, so we figured out a pretty simple way to do it all. It adds a small ratchet block to the back of the existing headknocker, and routes the finetune externally. The plusses of this are that it's easy (especially relative to 88's system) to add to current booms, and is lower friction. The downside is you get less travel (but still more than enough) and have some extra line hanging from the boom. I was worried about the extra line, but seeing it in person it doesn't seem like it will be any kind of problem, since the line is kept taught, and by using a tiny carbo block it can even run through existing mainsheet keeper rings on the boom.

Installation is relatively easy: drill and tap a padeye for a block into the back of the boom, and drill out an attachment for the little headknocker on the big one. Then it's just a matter of creatively reeving the lines through the fiddle blocks.
The parts total for this is less than $200 if you keep your old mainsheet, and the install shouldn't take a handy person more than 3 hours. The only tricky bit is drilling out the headknocker, as it's SS plate. Next one I make I'll try using a padeye mounted to the back of the trigger cleat to hold the little ratchet, which will be cleaner, but we'll see if it puts the headknocker too low in the cockpit.

Sunday, February 1, 2009

Boom on boat

Kevin (150) showed his boat at the Chicago Strictly Sail show, which is great since he definitely has the prettiest Shields around. His boom was elsewhere, and I wanted to try out our new spec boom, so it made a lot of sense to put it out for the show as well.

Everything seems to be the right length, so I'm going to use this boom with very few mods for our 09 season.

The outhaul is 8:1, and very low friction. The Harken 291 makes a great control terminal, as any of the 3 forward crew can adjust it from the rail. The mainsheet turned out better than expected, and will give our trimmer a lot of power in adjustment in big breeze. Here are some photos of it all:
Heres our boom from the gooseneck to the outhaul control cleat.

We tried this last year, and it works great! It's a Tylaska S3 soft shackle, spliced into a tail of 5/32" New England Endura 12, which has been coated in maxijacket to add some UV protection. The gold colored strap off the back is for hanging the boom off the main halyard.Heres our somewhat unusual mainsheet tackle. Usually the 4:1 dead ends on a fiddle block, but ours jumps up back into the boom, where it joins a hidden 2:1 purchase to make up our fine tune 8:1.

Heres our mainsheet(s) cleat arrangement, and our vang attachment. We chose to do a single line, spliced together and running through 6 holes in the boom. This spreads the load across a larger area of the boom than the single bolt we had last year. The little "headknocker" is a Harken 291, and controls the fine tune. The big one is a 2145, which is nice since it has an adjustable angle cleat and an automatic ratchet. The black fitted attachments are delrin, although I may change that system to fasten to the boom better.