Westsail Owners Alliance - Thread: "Pressure On Sheets"
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Thread: "Pressure On Sheets"

12,268 posts on 2,444 threads   •   From Mar 07, 2004 - Jan 08, 2012

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Pressure On Sheets


Terry Shoup

Anyone have a good guess as to how much pressure (tension) there is on the staysail sheets on a WS32? I'm going to replace some deck hardware, and while I don't mind going a little on the over-engineering side, I sure don't want to err on the low side! Based on my own experience, I'm guessing a couple of hundred pounds maximum.


Dave King
(Member)

Ahoy Terry, Grab a pencil. Your guestimate is quite accurate. At 15K the TOTAL pressure on a 149 sq.ft. staysail is about 134#. The clew, representing 1/3 of this, is 44#. At 30K the pressures are 536# and 177#. At 50K, approaching the maximum you'd ever use this sail, the pressures hit 1490# total and 492# on the clew.
These pressures are static loads only and must be adjusted for the "jerk factor". A doubling of the load on the clew can easily occur during a flogging episode. This raises the pressures at the clew to 88#, 354#, and 984# respectively.
To complicate things a bit, If you have a staysail traveller with a 2 to one purchase on a single sheet, like Saraband has, then the above clew pressures are cut in half approximately. That would then equal the original 44# (plus friction in the blocks), 177#, and 492#.
I hope this has been of some help. Good luck on the re-do. Dave


Gerald Astrella and Cathy Calisch

Hey Dave maybe you can help me out too. What size winch seems to be the best when changeing from club foot to loose footed stays'l. I know you prefer the club and I haven't made the decision to jump just yet, but-. I would be using the sail as a storm jib if needed with or without a reef.


Dave King
(Member)

Ahoy Gerald, I believe that #16 winches would be more than adequate when used with an 8" or 10" winch handle. Saraband and many other W-32's have no winches. Just a cleat. Perhaps some other owners can chime in here and tell us what they are using.
Also, play around with the location of the winches before installation as the dodger frequently is in the way of proper usage.


Gerald Astrella and Cathy Calisch

Thanks Dave. Glorious has the same single cleat for the self tending sail. I notice there is very little tension on that sheet (2:1 purchase I believe). Yep, there is not much room under the dodger. Hey, I am surprised you did not try to talk me out of the conversion. It would make life a bit simpler and maybe I could get to that bright work, paint, upholstry etc., etc. and so on.
Gerald

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