Thursday, January 22, 2009

More Boom

Got some more work done on the boom, and have a couple photos, and even a video. Yes, a video... of a boom. It's really cold in Chicago, ok?

This shows the arrangement and location of our mainsheet blocks and cleats. The big one is a Harken 2145, mounted to the boom with fitted delrin shims, but I'm going to remount it with a slightly different shim. The small one is a 291 with the cam cleat reversed.
The gross tune is the stock shields 4:1 purchase, but reeved so that the end of the line goes into the boom rather than dead ending on the fiddle block. Reeving the line like this makes it possible to get the boom closer to the deck, since the blocks can get closer by going side by side. Inside the boom there is a 2:1 purchase attached to the tail of the gray mainsheet, which makes it 8:1. This fine tune exits the boom forward through a 242, and ends up back at the cleats.
This is how it all works: The gross tune is used to trim the boom in to an upwind setting. Then the last couple inches are pulled in using the finetune, with twice the power. The finetune is used to make small adjustments while sailing upwind. At the windward mark, both can be released for a quicker ease of the sheet.


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