Boat Lift cable specs?

[gstanton]

I have a 10,000 lb ABL boat lift and one of the cables has a small kink or fray in the middle of it. I can replace it easy enough but I'm I'm a little hesitant. The stainless 1/4" cable at the hardware store is rated at 1400 lbs. So the cable comes down from the top channel down to a single pulley and back up to a long rod that winds the cable up, thus raising the boat.
There are 4 of these, one on each corner. Am I correct in thinking that each corner is 2 times 1400 lbs = 2800 lbs per corner (because of the pulley). 4 corners times 2800 lbs = 11,200 lbs lift capacity.
Agree or disagree?
There is no help online and I really don't want to pay some lift repairman $$$ for something as simple as replacing a cable.

THX!

 

[Shizzy]

Re: Boat Lift cable specs?

math looks go to me.

 

[Bob_VT]

Re: Boat Lift cable specs?

Wire rope Do your shopping on-line for stainless mil spec wire rope. The 1/4" stuff is normally rated at 8000 lb breaking strength for 1x19 strand.

We used to re-rig our cranes and our equip winches all the time and yes it is easy to do.

You can normally contact a US Maker of the wire rope to find out where to order it.

I just do not trust the wire rope from the hardware store....... if you buy it from a marine store you will pay really high prices..... call a company such as Loos and they will help. Depending on how much you need and how old the stuff you have is.... you might consider replacing all the cables.

 

[marine4003]

Re: Boat Lift cable specs?

your math is right..also every time you run the cable thru a pully you double the capacity....lifts are underrated for safety...consider a 10K lift will be closer to 12K lifting capacty..but VT's right,theres lots of places to buy 518SS cable..but the hardware store isn't one of them.

 

[Bigprairie1]

Re: Boat Lift cable specs?

If you are intent on doing this yourself you have some due diligence homework to do. I agree with the other guys with their take on this problem.
First and foremost, as Marine and Bob said do NOT buy this cable from the local hardware store. There is a very, very slim chance that it is the right cable for this lifting application.
I recommend you log on to: www.thecrosbygroup.com and do some reading on lifting applications...you will find it interesting and informative. They are an excellent industrial supply source for such stuff.
As well, you can get some quicker simplified insight by checking out the basic info for wire rope cables on www.mcmastercarr.com who are another well known supply house.
The math you did was basically correct but I would add a little bit more info to that. There is a substantial 'safety factor' in any lifting application. You will never know what it is but it is often twice (or more) than the listed rating.
Regardless, its not there to be taken for granted and minimized. Stay with the program and never cut corners on this kind of thing...ever.
As well most (4) point lifting applications are usually sized to hold the rating capacity on any (3)...not (4) points in case of not only failure but improper tensioning. Again, as long as you replace the cable with the correct one and install it correctly this info should only add to your sense of security.
I can not emphasize enough tho'....don't cheap out and don't cut corners. You do so at your own peril if you do. Its not hard or expensive to do it right...just do your homework on it.
Take your cable with you to an industrial supplier who deals in safety supply and he should be able to help you replace it.
Good luck and keep us posted on the results!!
BP

 

[gstanton]

Re: Boat Lift cable specs?

Excellent advice from everyone! I had no idea that there is a stronger wire rope! That's just the kind of information I needed.
I'm on it!


Thanks!

 

[Bob_VT]

Re: Boat Lift cable specs?

If you are ever close to a sailboat..... check out the stainless steel cables used and then look at the stuff in a hardware store again..... it will be obvious.

I do use the 1/4" plastic coated for my 100' dog run in my yard

 

[The_Kid]

Re: Boat Lift cable specs?

According to the ABl site http://www.ablboatlifts.com/specs.html your lift uses 4 30' 5/16 type 304 stainless cables. It's probably 7X19 since it's more flexible than 1X19.

 

[gstanton]

Re: Boat Lift cable specs?

Thanks to "The Kid"... I had been to the ABL website, but when I was there, there were dead links and no prices or ordering info. Still no prices or ordering.
Nor did I see the specifications like your link refers to. I've e-mailed them (which wasn't there either) to get their take on the cable.
I guess they are not very web friendly or under construction?

Anyway, we're on our way now!

 

[Bob_VT]

Re: Boat Lift cable specs?

Specs

http://www.alpswirerope.com/pdf/a.pdf

 

[Tim Frank]

Re: Boat Lift cable specs?

These guys have what you need.

http://qualitychainandcable.com/ecom/category/3/

 

[Phantom_II]

Re: Boat Lift cable specs?

There are 4 of these, one on each corner. Am I correct in thinking that each corner is 2 times 1400 lbs = 2800 lbs per corner (because of the pulley). 4 corners times 2800 lbs = 11,200 lbs lift capacity.
Agree or disagree?

Don't forget that while pulleys reduce the force required to lift an object by increasing the length of the pull, they don't actually reduce the weight of the object.
You may only need a 1400 pound pull to lift the 2800 pounds, but the weight is still 2800 pounds and the cable needs to be rated for that weight.

 

[joed]

Re: Boat Lift cable specs?

The only flaw in your calculation is ASSUMING that the weight on each corner is equal. The stern of the boat with the engine will weigh more than the bow.