how are winch sizes measured?

[Burnham_Bob]

The size of a winch was described to me as a '30' what does the refer to? I know it's a dumb question but I can't find a description anywhere......lots of sites with different sizes on but no idea of what to measure etc......

 

[Evadne]

I think you'll find it's a Lewmar 30 (e.g. ) or similar.

 

[Fergus]

http://www.harken.com/winches/BrionToss_Winchpower.php

 

[macd]

As the links above describe, it's the winch's power ratio. Most current winch manufacturers use a similar convention for expressing this, so a Lewmar 30 will be similar to, say, a Harken 30 in size and power. However, it is not completely universal, so there are exceptions, such as Enkes.

 

[Endeavourquay]

power ratio, so that would be 30 times the effort you put in, /forums/images/graemlins/grin.gif

 

[snowleopard]

Assuming a handle of 'standard' length.

 

[Strathglass]

[ QUOTE ]
The size of a winch was described to me as a '30' what does the refer to? I know it's a dumb question but I can't find a description anywhere......lots of sites with different sizes on but no idea of what to measure etc......

[/ QUOTE ]

It is the ratio of the power to the winch handle relative to the pull on a rope wrapped round the winch - Assuming no losses.


The normal practice by winch manufacturers is to assume a 10" handle will be used.

On most winches (typically Lewmar/Harken) it is calculated by multiplying the ratio of the length of the winch handle (10") to the radius of the drum by the reduction ratio of the drum.

The reduction ratio of the drum can be measured by counting the number of times the drum rotates for one complete revolution of the handle.

Does that help?

 

[VicS]

[ QUOTE ]
Does that help?

[/ QUOTE ] It shouldo!

Taking the figures for a Lewmar30 (from a rather old catalogue) The drum diameter is 74mm, therefore the radius is 37mm The 2nd gear ratio is 4.3:1 and taking the handle as 250mm

250 x 4.3 / 37 = 29