Peter, I have an early C&C 25 which has the same mast cross-section and mast step as the 27.
I added a boom vang about 5 years ago. The riggers put a bail around the mast itself. They installed reinforcement plates on each side of the mast where the bail attaches, as is recommended for highly loaded bails. The boom has the same thing. I'll send you a picture off-list. I've had no issues with it, but if I were to do it again, I'd put a wider bail around the mast step as you are considering and not put the holes in the mast. That 45 degree side plate shown in your photo isn't factory. It looks like bent sheet metal and maybe a little weak for the task. Here is something similar but beefier from the CC27Assocation website. http://www.cc27association.com/fixes/various/source/mastbase.html With your arrangement the boom vang also puts a side load on the 45 degree side plate. Mark ----- Original Message ----- From: Peter Fell To: cnc-list@cnc-list.com Sent: Sat, 20 Jul 2013 02:18:39 -0000 (UTC) Subject: Stus-List Boom Vang for C&C 27 Mk III My C&C 27 has a mast-step that looks like this: http://imageshack.us/a/img191/407/ubt7.jpg The previous owner had attached the 4:1 purchase boom vang to the 45 degree side plate which has resulted in bending the side plate! It was recommended to me to use a boom/mast bail bolted across the vertical portion of the mast-step bracket at the aft-most set of holes, with a bolt and filler ‘tube’ to avoid compressing the mast step bracket. Or to replace the aft mast-retention pin with the same set-up. Dimensions of the mast step (‘vertical’ bracket) are: Outside width = 5 inches Inside width = 4-1/4 inches Hole diameter = 7/8 inches Pin diameter = 5/8 inches 2 problems I am finding: 1) I can’t find a 5-inch wide bail 2) The larger size bails I have found (maybe 4 inch wide is the largest I’ve seen?) use a smaller bolt than 5/8 inches and no meat to drill out the holes in them, so there would be a lot of ‘slop’ there. I’m also concerned that if the boom vang can bend that mast-step side plate, what’s it going to do to a side-loaded bail and/or the vertical mast-step bracket? So ... perhaps a mast tang / hound? (much as I hate drilling holes in the mast ... but multiple holes would spread the load). I have read somewhere that part of the side of the standard C&C mast section is thicker which helps with this sort of thing? Can anyone verify? Sorry, didn’t measure the mast width. There’s also the sail track there that would complicate a tang / hound installation. By the way, the previous owner also bent the heck out of the through-bolt on the boom bail. I’ve replaced that with a new SS bolt Thanks!
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