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#1
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Whinches guide for selection of Which?
Hi
Does anybody know the coolest and best guide for selection of whinch size and power ratio for ones boat. Mads |
#2
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wrote in message oups.com... Hi Does anybody know the coolest and best guide for selection of whinch size and power ratio for ones boat. Mads http://www.lewmar.com/ Lewmar have a selection guide, under product/winches... then select a range, some have a selection guide |
#3
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I have found that the manufacturers sites tend to oversize winches. It is
fairly easy to calculate the theoretical power ratio needed. It depends on how much pressure you are willing to put on the winch handle on those last 3 or 4 turns. That can vary a lot depending on the location of the winch. If you have to kneel over a cockpit seat to crank you can't handle as much as you can standing. Here is how I figured my primaries: All my winches are positioned so I can stand and brace my knees on the cockpit side to crank them but I will be 62 before I can do it so I used 20 lbs as my goal. The formula for sheet load is: sail area * wind velocity^2 * .00431. Use a #3 or 100% jib for the sail area not a big Genoa. My foresail area is 505 sq. ft. and maximum wind before reefing is 20 knots so 505* 400*.00431= 870 pounds. Allowing 20% for friction loss the winch needs to handle 1,050 pounds Dividing by 20 comes up to a power ratio of about 52.5. The Harken site recommends a 56. You can still find 56STCs but Harken is no longer listing them as an active product so I might have to go with a 60 to meet their suggestion. The B60.2STC cost about $1K more than a 53. Power ratio is figured with a 10" winch handle so I think I am going with the 53 and if it gets to hard to crank invest in a 12" winch handle. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com wrote in message oups.com... Hi Does anybody know the coolest and best guide for selection of whinch size and power ratio for ones boat. Mads |
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