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Old 16 May 2007, 07:35   #21
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Country: UK - Wales
Town: swansea
Boat name: Too Blue
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I think those cheap winches are a bit generous on their ratings. The 3/16" wire used on most of them is pretty near it's breaking point at that sort of load. Even the expensive winches used on Land Rovers etc are rated at about the breaking strain of the wire itself. Not a very safe way to operate. Industril products are very different. My Tirfor hand winches for example have a 4:1 safety margin. The wire is far thicker than anything you would see on the front of a 4x4.

You are qiuite right about the tow hitch being man enough - their SWL is 5 tons on Land Rover. They will obviously take a lot more than that.

Good point about stones etc in the way - they increase the load a huge amount until the wheel has ridden over it.
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Old 16 May 2007, 15:01   #22
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Quote:
Originally Posted by codprawn View Post
Don't you think 7.5 tons is a bit of overkill? You could lift almost 4 of your boats vertically with that!!!

Remember these small electric winches have wire with a SWL of only 800lbs and a breaking load of about 1.5 tons.

Rather than the wire or rope my main concern would be the loading on the jockey wheel. Lowering is fine but pulling back up a slip can place huge loads on the wheel - especially if the car is over the lip on a short slip - then you are pulling down and there is a lot of force on the front.
overkill for this boat but i have them for pulling far heavier things as well, the safety margin is generous and also with wear when dragging i have no issues from a safety point of view, plus they cost not much more than ones that have a swl of much much less

when i looked into the winchs i seem to remember the load is measured for the first layer of wire on the drum and then the capacity drops off as more wire winds onto the drum and speed can seriously reduce as the load gets heavier

worth looking into carefully i think

i am also going to be getting the most sturdy jocky wheel i can buy with a pneumatic tyre, should be ok then i think
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Old 17 May 2007, 09:47   #23
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these are the ropes i got if that helps you with the decision around a winch or ropes...

http://rib.net/forum/showthread.php?p=199982#post199982

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