What do winch numbers mean?

jerrytug

jerrytug

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Hello a quick question, winches have numbers, eg 16, what do they relate to? Why don't they just use the drum diameter?
I was thinking of going ST but I don't know where to start comparing prices, I am probably missing something very obvious..thanks Jerry
 
Dunno about that.
For a non geared winch & standard handle the SMALLEST winch will give bigger leverage (power) than the larger ones, (but probably not be strong enough to sustain it)

Gearing changes it altogether, and cannot be a function only of drum diameter.
 
chewi said:
Dunno about that.
For a non geared winch & standard handle the SMALLEST winch will give bigger leverage (power) than the larger ones, (but probably not be strong enough to sustain it)

Gearing changes it altogether, and cannot be a function only of drum diameter.
Click to expand...

From their website;

Winched purchases. To decide the purchase required in a system controlled by a winch, calculate the winch output by multiplying 15kg for a single handed, or 25kg for a double handed winch, by the winch model no. (44, 48, etc.) On Lewmar and most other brands, the winch number is also the highest power ratio the winch can provide when
using a 250mm/10" winch handle.
Click to expand...
 
The mechanical advantage is gearing*(radius of handle)/(radius of drum).

What Lewmar say in their example about the bigger, geared winches is presumably true, (as the gear ratios can make it true), but it does not make sense in the context of an ungeared one, as that would imply the 16 has more power than the 8.
The 16 has more strength, but cannot have more power without gears.


For a given say 10" handle, I would get more mechanical advantage (leverage) from an 8 with smalll drum than I do for a bigger 16, neither being geared, though I would not like to subject the 8 to the loads the 16 takes, it would break.
 
chewi said:
The mechanical advantage is gearing*(radius of handle)/(radius of drum).

What Lewmar say in their example about the bigger, geared winches is presumably true, (as the gear ratios can make it true), but it does not make sense in the context of an ungeared one, as that would imply the 16 has more power than the 8.
The 16 has more strength, but cannot have more power without gears.


For a given say 10" handle, I would get more mechanical advantage (leverage) from an 8 with smalll drum than I do for a bigger 16, neither being geared, though I would not like to subject the 8 to the loads the 16 takes, it would break.
Click to expand...

Lewmar 16 has gears.
 
chewi said:
maybe the current one has, but the pair on my boat don't have. they just ratchet!#

http://www.lewmar.com/products.asp?id=8151&channel=1
Click to expand...

It may only have one speed, but it is still geared. A Lewmar 16 drum doesn't rotate at the same speed as you turn the handle like the 6 and 8. There is a reduction gear so the mechanical advantage of the gearing and the length of handle/ drum size equates to 16:1 power multiplier.
 
TimBennet said:
It may only have one speed, but it is still geared. A Lewmar 16 drum doesn't rotate at the same speed as you turn the handle like the 6 and 8. There is a reduction gear so the mechanical advantage of the gearing and the length of handle/ drum size equates to 16:1 power multiplier.
Click to expand...


I am not confused.
There are no gears on mine of 1997 vintage , the drum sits on the pivot. there are no cogs, just pawls top and bottom.
That makes it single speed ungeared.
 
chewi said:
I am not confused.
There are no gears on mine of 1997 vintage , the drum sits on the pivot. there are no cogs, just pawls top and bottom.
That makes it single speed ungeared.
Click to expand...

Fair enough. But I've been back through the service manuals I have to 1981 and I can see no record of your model. They do however consistently say that "the winch size refers to the power ratio i.e. a Size 40 winch has a 40:1 power ratio. This means if you put 55lbs of effort on the handle, the pull generated will be approximately 1 ton."

Yours is probably the exception that proves the rule.
 
It surprised me how, length for length, those seemingly overpriced 'power' handles really do effectively enable more of the human effort bit to be applied , vis a vis a placcy handle with short, spindly thin hand grip without thumbstop, and running on plain bearings and poor overall ergonomics .

Obvious in retrospect . Arguably an inexpensive power upgrade too, along with battery/drill combo winch handles that people have tried...?
 
Last edited:
I got out to the boat tonight.

I am eating humble pie for dinner.

I was wrong on two counts, my ST16 is geared and it winches in reverse drirection to the drum.

Feeling very small now.
 
chewi said:
I was wrong on two counts, my ST16 is geared and it winches in reverse drirection to the drum.
Click to expand...

Does that mean that you are like my sailing mate who is never confident of winding a sheet round the winch the right way until he has twiddled the drum with the other hand first. (But never has a problem with unscrewing the gin bottle cap the right way!)

BTW Though I have never met one, I have heard of port and starboard winches that rotate opposite ways, giving a perfect symmetry...

Mike.
 
mjcoon said:
Does that mean that you are like my sailing mate who is never confident of winding a sheet round the winch the right way until he has twiddled the drum with the other hand first. (But never has a problem with unscrewing the gin bottle cap the right way!)

BTW Though I have never met one, I have heard of port and starboard winches that rotate opposite ways, giving a perfect symmetry...

Mike.
Click to expand...

:-)


I have been known to do that, but the self tailer leads you into wrapping it correctly.

I'm not a gin drinker, cans open symetrically, just pull!

I had a pair of small tufnol winches on my old vivacity 650 that could be configured as you say.
 
mjcoon said:
BTW Though I have never met one, I have heard of port and starboard winches that rotate opposite ways, giving a perfect symmetry...

Mike.
Click to expand...

I used to sail on a couple of boats that had paired winches like these. On the port winches you wound the sheet on clockwise and on the starboard side the sheet went on anticlockwise. Caused no end of confusion to those of us who regularly crewed on any boat that would have us and were used to all winches being clockwise loaded. Possibly that was the cause of the skipper of one of these boats becoming rather heated and yelling at his daughter-n-law "the other way round the f****** winch ye daft c***." He always apologised to his crew after each race for beconing over-excited but I was surprised that he never ended up with a sheet wrapped round his neck.
 
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