Weight Capacity for U-Shaped Pontoons | Christopher in Louisiana

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Discussion Overview

The discussion revolves around estimating the weight capacity of U-shaped pontoons intended for a floating camp. Participants explore the implications of the pontoons' dimensions and shape on their buoyancy and weight capacity, considering both full submersion and partial submersion scenarios in fresh water.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Christopher in Louisiana seeks to determine the weight capacity of his U-shaped pontoons based on their dimensions: 5ft 3in wide, 3ft tall, and 20ft long.
  • One participant provides a rough estimate of 19,000 pounds for the weight capacity based on a cubic volume calculation, assuming rectangular dimensions.
  • Another participant challenges this estimate, noting that the assumption of rectangular shape may not be accurate and that the U-shaped cross-section could significantly affect the volume and thus the weight capacity.
  • Christopher clarifies that the pontoons are not U-shaped in their overall structure but have a U-shaped cross-section, which may influence the calculations further.
  • Humor is introduced regarding the weight capacity being less if the pontoons were floating in a denser liquid, such as crude oil.
  • Concerns are raised about the environmental impact of oil spills, although this topic diverges from the main focus on weight capacity.

Areas of Agreement / Disagreement

Participants express differing views on the accuracy of the weight capacity estimate, with some agreeing on the rough figure while others contest the assumptions made regarding the shape of the pontoons. The discussion remains unresolved regarding the exact weight capacity due to these differing interpretations.

Contextual Notes

The discussion highlights the importance of accurately defining the shape and dimensions of the pontoons, as well as the assumptions made in the calculations. The potential influence of the pontoons' cross-section on buoyancy is noted but not fully resolved.

christoph8025
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I recently bought some pontoons to build a floating camp on. I was wondering if you guys can give me the weight capacity the pontoons could hold at full submergersion and half?

The Pontoons are 5ft 3 in wide, 3 foot tall and 20 feet long. The pontoos are U shaped. The pontoons will be docked in fresh water if that make any difference.

You guys have answered similar questions like this before so hopefully yall can come through again.

Thank you for all yall help and I can't wait to get some results.

Christopher in Louisiana
 
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A rough guess would be 5×3×20 cubic feet × the weight of a cubic foot of water of about 64 pounds, or 19,000 pounds would be required to submerge one of them.
 
Wow that's awsome. Thanks for the calculation and that just made my day better!
 
I think JDLugosi's answer is a bit premature.

1] JD has assumed the pontoons are rectangular. A 5x3x20 round pontoon will have a smaller volume (though not by that much - he did say rough guess).

2] My bigger concern is: What do you mean U-shaped? That can make a big difference in the derived volume.

Do you simply mean its cross-section is U-shaped? My first thought was that each pontoon was bent into a U like a zodiac inflatable boat.
 
Last edited:
JDługosz said:
A rough guess would be 5×3×20 cubic feet × the weight of a cubic foot of water of about 64 pounds, or 19,000 pounds would be required to submerge one of them.

Less of course, if you are floating in light sweet Louisiana crude. ;))

..
 
The pontoons are not made in the shape of an U. I just meant the cross section of the pontoon resembles a U.

Lets not even get into the OIL BLOW OUT! BP is a joke! They are killing our way of life and our wetlands and a entire ecosystem. And no one outside of the state seems to be worried about it. We supply 34 percent of the whole United States with entergy and no one seems to be worried about that either!

But anyway...

Chris in Louisiana
 
Creator said:
Less of course, if you are floating in light sweet Louisiana crude. ;))

..

OK, that's funny.
 
christoph8025 said:
The pontoons are not made in the shape of an U. I just meant the cross section of the pontoon resembles a U.

Lets not even get into the OIL BLOW OUT! BP is a joke! They are killing our way of life and our wetlands and a entire ecosystem. And no one outside of the state seems to be worried about it. We supply 34 percent of the whole United States with entergy and no one seems to be worried about that either!

But anyway...

Chris in Louisiana

that's pretty close to rectangular so I think 19,000 pounds is a very reasonable estimate.
 
DaveC426913 said:
2] My bigger concern is: What do you mean U-shaped? That can make a big difference in the derived volume.

I supposed it to be a "rounded corner rectangle", not a substantially smaller shape. In any case, I figured by showing the work used to compute it, it would help him see how to do it, or at least serve as a strawman to start refining a better answer.
 

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