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Winch gear ratios

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11K views 7 replies 6 participants last post by  roline  
#1 ·
I'm trying to sort through the different older winches to find out which one is suitable, but am having very little luck discovering a site that lists these kinds of specs plus mounting base dimensions. Mostly interested in Barient and older Lewmar. Specifically 23, 26 and others. Many sellers list the overall mechanical advantage, but with no drum diameter of length or length of winch handle, it's hard to decipher. Anybody know either a site or the answers?

Duncan52
 
#3 ·
I have a simple way to find out which winch is suitable.
Sail Force = v*v/80 kg where v is wind speed in knots. Normally for winch selection 50 knot wind speed is to be used. But you can use any speed you want.
If we assume it as 50 knots then Sail Force came out to be as 31kg.
Then calculate the sail area by taking into account for which sail the winch is to be used.
Sail Area x Sail Force will give you the Max Force which your winch needs to tackle.
Assuming by your arm you can only aplly 15 kg force and by dividing Max Force to 15 will give you approximate Power Ratio of the winch required.
Where
Power Ratio=(L/r)*GR
GR= Gear Raito of winch
L=Length of handle to be used
r=Winch radius
So if you can find Gear Ratio and radius of winch it is easy to decide.
 
#6 ·
If you have the winch you can find gear ratio by turning it.
If you do not have the winch and are looking for the GR of Barient 22 it is again easy. Generally the numbers given in the specification of winches denominates its Power Ratio. If you know the PR you can find GR if you know the diameter of the winch. Generally winch specifications are given 10 inch handle. For your case:

GR=22/(10/r)