Will 24-inch PVC pipe work for pontoons?

I located an inexpensive source of 24-inch PVC Schedule 40 pipe. The wall thickness is around 2/3rds of an inch.

How much weight would 3 pontoons 30-feet long float?

Is there a reason why PVC would be a poor choice for pontoons?

 

I reckon each pipe will have a cross-sectional area of material of 48.9 in2, so 30ft will have a volume of 17,500 in3. Each 30ft pipe weighs about 897 lb, and displaces about 94 ft3 or about 6,000 lb of seawater.

PVC is used for water pipes and sewage pipes, so I guess it should be resistant to anything it would be in contact with in the water. Some types of PVC have toxic additives which can leech out, but you don't get these in pipes used for domestic water.

 

PVC is heavy for what you get...for pontoons you want to have half or less of the pontoon submerged.

Your pontoon will displace pi r^2 x (360 inches) or 3.14 x 144 x 360 = 162777.6 cu in/1728 cu in per cu ft = 94.2 cu ft/2 = 47.1 cu ft x 64 lbs/cu ft = 3014.4 lbs

from that you will have to subtract the weight of the pontoon itself including the end caps so if they weight in at around 900 lbs your pontoon will displace 2100 lbs at half submersion...3 of them will support 6300 lbs total in salt water...less in fresh or brackish. PVC is brittle and would probably crack...schedule 40 is pretty thin.

 

?????

Depends a lot on what the pontoons are for...

-Tom

 

keep in mind also that pvc is known to break down and become much more brittle with exposure to sunlight over time.

 

Cracking would be my worry. Can you get HDPE or PEX?

 

Sun won't hurt them if you put a good UV paint on.

 

Granted the threat is based on the ready availability of cheap PVC pipe, but if you have the opportunity, look at ABS. I spent too much time reading spec sheets when I was planning to build a potato cannon, but the take-away was that ABS fails in a ductile manner at room temperature while PVC fails in a brittle manner.

Or, put another way, ABS will bend when you hit it with something, PVC will shatter.

 

Fill it with foam. Gives it move rigidity and won't let it break, or leak.

 

we've all thought about it. But is it worth the effort for what you get?

I've though about using fiberglass pipe as pontoons. Heavier than aluminum, but not too bad for a larger boat. I'd have the cap the ends and make a cone if I want it too move through the water smoothly. For what's involved I don't know if it'd be much better than buying pontoons, even if I can get the pipe for free.

 

There are several problems with PVC. As mentioned is the weight. Next is the brittle nature of the material, especially as it ages or receives UV damage. PVC is generally, not self supporting. In other words if you took a crane and lifted just one end of the pipe, it will bend dramatically, probably breaking from it's own weight. Filling it with foam will help this to a degree, but not for long as the foam will likely shear for adhesive contact with the inside of the pipe (differing expansion rates), which will defeat it stiffness attribute. The biggest issue I see is attachment to other stuff. It welds well, but that's about it. If it's drilled, it's brittle, there's no glue that stick well to it, though a heat treated surface and epoxy will show fairly good adhesive qualities. Attaching cross beams and other frame work necessities will be problematic at best.

In the end, a fragile and heavy craft will be deployed.