Group: Forum Members
I lean toward option #1 with the thinking largely along similar lines. My thinking is as follows.
If I am correct in reading your well labeled photo, that is a lot of line to make what are likely, given fairly modern sails, are quite modest lengths of mainsail clew adjustment (6-8 inches maybe) to achieve the needed variations in sail shape. I also assume that the rifle shot noise is made by the aft-most block when the boom jumps violently when the sail slats. I suspect that the forward block may make some noise, but far less as it is closer to the pivot point, the gooseneck, and therefore less susceptible to “whipping” back and forth.
One possibility which I think could be easily executed would be to decrease the throw (the distance from block to block) to just a few inches longer than needed and then to move the blocks forward toward the gooseneck. This would leave the “design” intact while adjusting the elements that enact the design.
Executing would entail: shortening or eliminating the pennant going from the forward block to the forward end of the boom near the gooseneck. Then add the now shortened-throw pair of blocks and figure how much to lengthen the pennant going from the aft block to the outhaul car where the mainsail clew is attached. This should now probably be of wire or high modulus line. And you should end up with a lot extra tension adjusting line.
In this way, both blocks would be much farther forward, near the boom’s pivot point and unlikely to whip around making the offending noise.
As I see it, there was never a reason to have such a long throw between blocks: this decision set up the noise you referred to.
Please let me know how this works. I am aware there are a couple of assumptions made and things I was unsure about.
My best, Dick Stevenson, s/v Alchemy
As an aside: annoying, especially unexplained, noise, even if not overtly offending should always be explored as it usually means chafe, something is poorly designed or something is going (gone) pear shaped. For example, in this case, if let go on, I would suspect, in time, damage to the block