Trying to figure out weights for boat dry dock

[durangod]

Hi, sorry i know little to nothing about advanced math, they didnt really stress it when i went to school and i never learned it.

What i am trying to do is build a boat dry dock. That just means that i want to lift my boat off the trailer (on land), then pull the trailer out from under the boat so i can work on the trailer. My idea involves 4 4x4 wooden posts, 2 boat winches, and two heavy duty straps rated at 2000 Lbs each.

I puchased the hand crank winches today and they are rated for 1000 lbs each. I though my boat was under 1000 lbs but its not. So i need to exchange the winches for 1200 lb versions if i cant lift the boat.. And that is where my challenge is..


I need to know how much weight each winch will need to support. Is it total weight divided by 2, or does each winch have to hold the full weight of the boat.

Here is an image to try to explain my idea. The boat weights 1085 lbs, and the motor weights 400lbs, winchs (2) are rated for 1000 lbs, each, and strap is rated at 2000 lbs each

the idea is to put the straps under the boat, and winch the straps till the boat comes off the trailer, then pull the trailer out. Then ill support the boat with some physical supports while i work on the trailer, but it will remain suspended on the straps as well.



Thanks

 

[NobodyAnyone]

Hi, sorry i know little to nothing about advanced math, they didnt really stress it when i went to school and i never learned it.

What i am trying to do is build a boat dry dock. That just means that i want to lift my boat off the trailer (on land), then pull the trailer out from under the boat so i can work on the trailer. My idea involves 4 4x4 wooden posts, 2 boat winches, and two heavy duty straps rated at 2000 Lbs each.

I puchased the hand crank winches today and they are rated for 1000 lbs each. I though my boat was under 1000 lbs but its not. So i need to exchange the winches for 1200 lb versions if i cant lift the boat.. And that is where my challenge is..


I need to know how much weight each winch will need to support. Is it total weight divided by 2, or does each winch have to hold the full weight of the boat.

Here is an image to try to explain my idea. The boat weights 1085 lbs, and the motor weights 400lbs, winchs (2) are rated for 1000 lbs, each, and strap is rated at 2000 lbs each

the idea is to put the straps under the boat, and winch the straps till the boat comes off the trailer, then pull the trailer out. Then ill support the boat with some physical supports while i work on the trailer, but it will remain suspended on the straps as well.

View attachment 31615

Thanks

Can you specify what u want me to help u with exactly. Cuz I do t think a got what u said.

 

[Dr.Peterson]

Hi, sorry i know little to nothing about advanced math, they didnt really stress it when i went to school and i never learned it.

What i am trying to do is build a boat dry dock. That just means that i want to lift my boat off the trailer (on land), then pull the trailer out from under the boat so i can work on the trailer. My idea involves 4 4x4 wooden posts, 2 boat winches, and two heavy duty straps rated at 2000 Lbs each.

I puchased the hand crank winches today and they are rated for 1000 lbs each. I though my boat was under 1000 lbs but its not. So i need to exchange the winches for 1200 lb versions if i cant lift the boat.. And that is where my challenge is..


I need to know how much weight each winch will need to support. Is it total weight divided by 2, or does each winch have to hold the full weight of the boat.

Here is an image to try to explain my idea. The boat weights 1085 lbs, and the motor weights 400lbs, winchs (2) are rated for 1000 lbs, each, and strap is rated at 2000 lbs each

the idea is to put the straps under the boat, and winch the straps till the boat comes off the trailer, then pull the trailer out. Then ill support the boat with some physical supports while i work on the trailer, but it will remain suspended on the straps as well.

View attachment 31615

Thanks

This is really a little more physics than math; and a careful answer would require more details (such as the weight distribution of the boat, and actual distances). But very roughly, if the straps are the same distance from the two ends (which they are not in your picture), then each would take about half the weight of the boat itself; and the one near the motor would take all of its weight. So the front strap would take about 545 pounds, and the rear strap would take about 545+400 = 945 pounds. With the arrangement as you show it, the rear strap would take even more of the total.

I'd also want to think about how well the posts will take a pull at an angle.