Build Boat Lift w/ 10,000 lbs Capacity: Tips & Advice

AI Thread Summary
To build a boat lift with a 10,000 lbs capacity using submerged plastic tanks, it's essential to apply Archimedes' Principle, which states that the tank must displace a volume of water equal to the submerged portion of the boat plus extra volume for the tanks' weight. Two 610-gallon tanks or one 1220-gallon tank are suggested to achieve this lift, as water weighs approximately 8.33 lbs per gallon. An electric motor with a reduction gearbox is recommended for reliable lifting, as it is more cost-effective and durable compared to air compressors or water pumps. The discussion also touches on the differences in gallon measurements between the US and UK, emphasizing the importance of accuracy in weight calculations. Proper understanding of these principles and equipment can lead to a successful boat lift construction.
Mfrank21
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I am trying to build my own boat lift that uses plastic tanks submerged to lift the boat when they become filled with air. My problem is that I need to lift about 10,000 lbs and i don't know how large the tanks need to be ( how much water they need to displace ) to lift that amount of weight. I am going to be using two tanks. please help!
 
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What you need is Archimedes Principle, but there's an easy way to do it for this application.

When the boat is afloat, it displaces a certain volume of water. If you want to "float" it above the water on top of a tank, the tank needs to be the same volume as the part of the boat that was below the waterline - plus a bit more volume, to float the weight of the tanks themselves.
 
why not use (2) 610 gallon tanks or One 1220 gallon tank to lift the 10,000 pounds. Water weighs 8.33 lbs per gal. at 70 degrees F. We usually use an electric motor with a reduction gearbox driven tooth gear , (a sprocket), which operates a chain that drives a sprocketed shaft that have cables that go through pulleys that lift a cradle that the boat sits in. The motor is able to operate clockwise and counterclockwise for up and down movement. very reliable and durable. These motors are easily found for outdoor environment..much cheaper than using an aircompressor or water pumps with large volume tanks.
 
Koonism said:
why not use (2) 610 gallon tanks or One 1220 gallon tank to lift the 10,000 pounds. Water weighs 8.33 lbs per gal. at 70 degrees F.

Or 10 lbs per gal, if your boat happens to be in the UK :wink:
 
The Boat probably weighs more overthere also, so it's all probably relative, ha, ha.
 
Nope, the boat weighs the same number of pounds, but UK pints and gallons are 20% bigger than US.

Which was not so funny, when somebody refuelled an aircraft using the wrong size of gallon...
 
AlephZero said:
Nope, the boat weighs the same number of pounds, but UK pints and gallons are 20% bigger than US.

Which was not so funny, when somebody refuelled an aircraft using the wrong size of gallon...
Been there. Thank goodness it was stopped before it happened.
 
I was joking about the weight of the boat. Doesn't an aircraft have fuel guages that are represented in lbs of fuel rather than gallons? Does the sensor in the fuel tank need re-calibration when the aircraft operates in a country with a different standard?
 
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