Is there a way to calculate the lifting capacity of a boat lift?

[RedneckRich]

I just bought a used boat lift but I don't know what the lift capacity is. Now don't get me wrong I didn't just go out and buy one without any way of knowing if it was adequate...The guy I bought it from had a boat that weighed out the same. I would still like to know what the lift rate is. It has two of the square poly tanks under it. Is there a way to measure the area of these tanks and get a estimate of the lifting capacity?

 

[DBreskin]

Re: Is there a way to calculate the lifting capacity of a boat lift?

You can measure the length, width and height of the tanks to calculate their volume. Fresh water weighs 62 pounds per cubic foot; multiply 62 by the volume of the tanks to calculate the total displacement. This is NOT the capacity of the lift since you need to subtract the weight of the lift, and there should also be a safety factor allowance.
The frame of the lift may have a much lower capacity than the displacement of the tanks might indicate. There's no easy way to calculate this since it depends on the gauge of the metal and design of the lift.

Or you could do it the Calvin & Hobbes way: keep adding weight until it collapses, then you'll know the capacity.

 

[lkbum]

Re: Is there a way to calculate the lifting capacity of a boat lift?

I agree with dbreskin, he is spot on. WIth square tanks, you most likely have either a Float Air lift, or Econolift. Float air - http://www.boatlifts-floatair.com/category/10
Econolift - http://www.econolift.com/