Pontoons

Hi guys...could anybody tell me how much weight pontoons 750mm wide by 600mm by 12 meters long would be able to manage...have included a sketch to look at.....
cheers

 

If length = 12 m :
H = 175 mm ......... V = 1,36 m3
H = 375 mm ......... V = 3,41 m3
H = 575 mm ......... V = 5,46 m3
H = 750 mm ......... V = 6,82 m3

See what is "H" in attached picture

 

Hi Tansl
The overall height from the bottom of the radius to the top is 950mm and 750mm wide....so total weight that 1 pontoon could carry is ...???

 

To the pontoon of picture :

H = 600 mm ......... V = 5,400 m3
H = 707 mm ......... V = 6,068 m3
H = 950 mm ......... V = 7,097m3​

With salt water (1,025 kg/dm3), the máximum weight, included pontoon own weight, is : 7,27 tons.

 

What is the reason for using the half round part on the bottom?

 

Hi...have seen others built this way here in Australia and thought i would make mine the same...do you know of a better design ??
Needs to be 12meters long and would like the pontoons to carry around 8-10 ton

Cheers

 

I see no reason for introducing the complexity of the half round part. The rounded part will add a little bit of bouyancy but not enough to compensate for the additional joint at the intersections. It would be much more practical to use a simple rectangular shape or perhaps a vee bottomed shape.

You have mentioned that the pontoons need to support 8 to 10 tons. Do you mean 8 to 10 tons each or is that a combination of two or more pontoons. Is this to be a boat that will be propelled? If so some attention to the ends of the pontoons would be in order. More than that you will want to take immersion of the pontoons into account.

Tell us more about the purpose and reqirements of the pontoons and we can be more helpful.

 

Hi Messabout
The weight will be on both pontoons...i will be shaping the front of them into a cone shape...the purpose of these pontoons are for a house boat and yes I will have a outboard motor setup either side..nothing to big thou..only to move from point a to b...
Cheers

 

If building a houseboat, you shouldn't give a whole lot of fiddling time to the pontoons. Make them rectangular, with the volume you need and move on to the next set of issues you have to contend with. It's a houseboat and motoring efficiency is a ridiculous concern. Rectangular pontoons will permit easy construction, uses less materials and are more then suited for their role in life.

 

Potoon

Hi...
This is the shape of the pontoons i want to make for a houseboat all measurements are in mm...the pontoons will be 13.2 meters long...can you please tell me the total weight both pontons would be able to carry half submerged...
Cheers

 

About 5000 kg

 

Aren't metric lengths derived from the weight of water? Like a cubic meter of water weighs 1 ton?

 

Indeed you are correct for fresh water at 25 c at sea level, and of course those are metric tonnes. But close enough for the calculations for a house boat.

OP, this is pretty simple math. Figure out how to make the cross section with rectangles and triangles. Rectangle area is width times height, triangle area is 1/2 width times height. Add up all the t's and r's in your pontoon design and that is the cross sectional area. Multiply times the length and the number of pontoons and you get the volume. Then do as Sam suggested and convert to tonnes. Simple as pie, easy as cake.

Teach a man to fish, and all that jazz.

Oh, and the fewer seams the fewer chances there are for seams to leak.

 

OK...Thnx guys
might not be the best at maths but make up for it in my welding skills...lol..

Will put updates and pics as the houseboat progresses over the next 3-4 months..

Cheers

 

I had edited and added to this post and then forgot to save it.

Anyway, aren't all metrics of weight, length, volume and temperature derived from water? They took a cube of water and said the length of one side of this cube is a meter, the weight of this cube is 1000 kilograms, the volume of this cube is 1000 liters and when water freezes is 0 degrees, and when it boils is 100 degrees. Isn't that how it went? How did they decide on the size of the cube to start with?