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Old 03-20-2009, 08:56 AM
benz benz is offline
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Join Date: Sep 2006
Location: Newport RI
Posts: 244
Default Running backstay location

Concensus seems to say that a running backstay's lower terminus should be midway between the transom and the mast. Is there any reason it couldn't terminate further aft, as long as there was nothing it would interfere with? I'd like to be able to easily reach it from the cockpit, rather than having to lay forward along the side deck every time I came about.
Boat is a Cape George 31' pilot cutter, disp. 16,000 lbs, gaff rigged.
Thanks,
Ben
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  #2  
Old 03-21-2009, 08:41 AM
Brion Toss Brion Toss is offline
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Join Date: Jun 2005
Posts: 1,180
Default Vectors

Hello,
Midway between the transom and the mast? That is an echo of reasoning, almost a superstition, and possibly exactly correct, darn it. But let's throw some rationality at the question. The runners oppose the pull of the forestay, and as such their power is limited in part by the relative angle they form to the forestay. The further forward their deck attachment, the more of their effect goes into pulling aft, and the more goes into compressing the mast. Go far enough forward and you have (shudder) aft-led intermediates.
By this logic, the best place for the runners would be as far aft as possible, but the returns diminish as the angle widens, and besides if you took the runners to your transom you risk a torn mains'l and/or a snagged boom, and you probably would foul the mainsheet and have a difficult lead to deal with.
One useful rule of thumb is that the runners should land about as far aft of the mast as the forestay is forward of the mast. This satisfies our vector requirement, and might, on some boats, be about midway between mast and transom. But what if that spot meant the runners fouled on the house side, or got in the way of a Genoa lead, or was smack in the middle of a deck traffic path? There's more going on here besides geometry. Depending on the boat the actual landing might be forward or aft of the rule, and inboard, outboard, or somewhere in between. On the 31, the deck narrows at the aft end of the house, so it is unlikely that you could get a direct lead to a Genoa winch, especially on port side, so the lead for the runners (and probably the Genoa sheets) would go to footblocks at the aft end of the cockpit. This would also leave those narrow decks clearer and safer for traffic. I'd but the padeyes outboard, a foot or two forward of the aft corner of the house. But I'd mock it all up in detail aboard first, and look for ergonomic exclusions.
Fair leads,
Brion Toss
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Old 03-22-2009, 06:39 AM
benz benz is offline
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Join Date: Sep 2006
Location: Newport RI
Posts: 244
Default

Thanks, Brion. There is a 'sweet spot' I've been eyeing for the padeyes just aft of the house, about eight feet forward of the transom. Forward enough not to foul the boom or the mainsheet, but aft enough not to interfere with the jibsheets or with going forward. It just seemed further aft than most running backstays I've seen, so I thought I'd ask.
Groping along,
Ben
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