Boat lift question

[Speedwagon]

So I have this boat lift, 2000 lb capacity. It's an older Shorestation, steel cantilever design, with canopy.<br /><br />Currently, my friend's boat is on the lift. Well, it was, until the cable snapped the other day. I found out today WHY it snapped, and it's because of a sharp 'tooth' in the wheel, that caused the 5/16" stainless cable to become frayed.<br /><br />While looking up lifts, I noticed that the 3600lb lifts use a pulley on them. And since my lift is sometimes hard to pull up(harder than I would like it), is it possible to add a pulley to this when I replace the cable, to make my life easier?<br /><br />If so, how do I know what rating of a pulley to get? I think it's reasonable to assume that the wire isn't lifting a full 2000 lbs, but what does it have to deal with?

 

[Texasmark]

Re: Boat lift question

Tractor Supply Co. sells pulleys and cables for industrial/ag applications; don't know if you need to go to SS on cables and pulleys or not; if so, then a marine/industrial supply should do you, or a full service marine dealer.<br /><br />The working load is stamped on their pulleys or on the id tag; same with cable. Don't know what to tell you on derating factors. Part of the reason is if a person is involved in any way (other than operating), the pulley cable system...like would anyone be in or under the boat when operating.<br /><br />I personally use 2:1 derating on my ag applications and use pulleys to multiply my winches capabilities. So I can do a lot of work with a small hp winch.<br /><br />By starting with a deadman and then going through 1 or more pulleys, I can also reduce the size of my cable by 2:1 for 1 pulley or more (multiples of the numbers of pulleys).<br /><br />Like on my hay truck, I anchor one end of the cable to the truck then go through 1 pulley and attach the boom to that pulley then go off to my winch. I just doubled my effort and halved the parts involved....except for the boom pulley which has full stress on it even though the cable through it has the stress split. Course the more times you multiply your leverage, you divide your speed....nothing's free.<br /><br />Just remember that whatever you anchor your pulleys to has to hold the stress.<br /><br />Mark

 

[Speedwagon]

Re: Boat lift question

Thanx for the reply. I ended up going to Farm & Fleet, and getting the biggest pulley I could find. 1250lb rating on it. Unfortunetaly, I used the wrong type of link to attach it to the chain, and the link snapped as soon as I started pulling the boat up.<br /><br />Another trip to the store, with a stronger link this time, and the boat is back on the lift. Significantly easier now with the additional pulley too, and using 1/4" steel cable(galvanized I believe). We'll see how it holds up!