Do I have this right about figuring minimum rated pull of a windlass?

[jim99]

I am considering replacing my manual windlass with an electric. My understanding is that the usual benchmark for determining the minimum rated pull of a windlass I want is calculating three times the weight of anchor, chain, shackles, etc.

I rarely use rope, so it's 100 metres of 6mm G4 (200#), anchor (heaviest is 35#), shackles (maybe 10# tops if I also use a swivel). So that's 245# X 3 = 735# or 335kg. The total figure becomes 855# (390kg) if I double anchor.

That eliminates a lot of highly-rated small boat windlasses, especially considering I rarely use two anchors and almost never use 100 metres of chain.

Is there a better common sense way of arriving at the minimum pull that I need?

cheers

 

[Salty John]

I had virtually the same ground tackle as you on my 33' heavy displacement boat and I used an Ideal Windlass with nominally 500 lbs of pull. That works with the 3 x calculation: 35 lb anchor, 100 feet of 1/4" G4 is 60lbs, say 10lbs for shackles, equals 105 lbs x 3 = 315 lbs. You calculate on a much longer length of deployed chain, I reckon you must have very deep anchorages, so your chain weight would be 170 lbs. You need a pull of 645lbs. I would reassess your deployed chain length/weight because it implies you anchor in depths of 70 - 100'. I think you would find a windlass of 500lbs capacity quite adequate.

 

[jim99]

Re: Do I have this right about figuring minimum rated pull of a windla

There's a few anchorages here that are 20-25 metres. Walls of coral prevent you from getting any closer in. So that's 4-1. I wouldn't want any less. US manufacturer tells me my chain is 200lbs. The windlass I wanted to buy falls a little short. Maybe I should make a deal with myself to pull in the first 30 metres by hand before turning the windlass on.

 

[GMac]

Re: Do I have this right about figuring minimum rated pull of a windla

[ QUOTE ]
I am considering replacing my manual windlass with an electric. My understanding is that the usual benchmark for determining the minimum rated pull of a windlass I want is calculating three times the weight of anchor, chain, shackles, etc.

I rarely use rope, so it's 100 metres of 6mm G4 (200#), anchor (heaviest is 35#), shackles (maybe 10# tops if I also use a swivel). So that's 245# X 3 = 735# or 335kg. The total figure becomes 855# (390kg) if I double anchor.

That eliminates a lot of highly-rated small boat windlasses, especially considering I rarely use two anchors and almost never use 100 metres of chain.

Is there a better common sense way of arriving at the minimum pull that I need?

cheers

[/ QUOTE ]

Unfortunatly that is the common sense way of working it out

You'll have 100kg all up (assuming 100mts) so 300kg Max pull winch is what you need. Most will do this easily.

We deal extensivly with many winchmakers and believe the following to be a fair statement;
A Maxwell will out pull most others followed by Lofrans and Quick then Muir back some more to Lewmar.

Maxwells published numbers are very true and possibly understated. Lofran and Quicks numbers are pretty good. Muir overstates a bit. Lewmars are just dodgy and quite limp.

I know a Maxwell Freedom 500 or HRC-6 will do your rode easily as will Lofrans Marlin/Project 500/Dorado and the Quick Aries/Aster/Genius. A Muir will also but do it a lot slower. The Lewmar will probably be slow but do it until it breaks down due to water getting into the cheap motor.

If you want some extra grunt get a Maxwell freedom 500 but with the 800 motor. You can do similar with most others, if you want to spent a little more, by getting a 8mm winch and a 6mm gypsy fitted. I wouldn't bother though.

 

[jim99]

Re: Do I have this right about figuring minimum rated pull of a windla

GMac,
Actually the Freedom 500 is one of the windlasses I was including in the "highly-rated small boat windlasses" that I thought were eliminated by my figures. It got great marks in comparison tests by Powerboat Reports, as did the Quick Crystal 1000 (slower, but a "stump puller") which was the way I thought I might go if I passed on the Maxwell.

And yes, windlasses with little more power often eliminate the availability of 1/4" gypsies. If I remember correctly, a while back I asked Maxwell if the 500 1/4" gypsy would fit the 800, and they said sure but I would have to pay extra for it -- they wouldn't provide it with the 800 -- which I thought was cheesy, so I decided to pout for a while. They didn't mention that the motors were switchable, if I understood that correctly.
Thanks for your input.

 

[GMac]

Re: Do I have this right about figuring minimum rated pull of a windla

Most winchmakers I know would have a gypsy that would take 7mm or 1/4" HT that would fit on either their '6-7mm' category and the '8mm' winches as well. This gives the option of smaller or bigger 'running gear'.

US 1/4" HT short link fits the same gypsy as 7mm DIN766/A short link. Both chains are basically the same size.

The bigger gear will cost more as you are buying a 8mm not a 6mm winch and only changing the gypsy.

I'd lean the Maxwell way personally both but are good.

How big is the boat?