Locating Large Diameter PVC pipe

There's got to be someone nearby who sells pipe. Ask a contractor. Corrugated plastic drainage pipe will work as well as sewer pipe, though the drainage pipe is probably cheaper. You probably want 12" but 8" maybe big enough.

Check Irrigation supply, Mechanical Contractors. Put an add on craigslist.

Call a pipe company and tell them you don't mine faded, discolored or hairline cracks. They come real cheap.

I am a sheet metal worker who used a 14" round aluminum spiral pipe(ductwork) for my sailtube in '89 for my Hobie 21SE.One end has a sealed end cap and the other end has a lockable,removable custom made cap.The 3 aluminum saddles that this spiral pipe sits in was the hardest part.Just cut your out of redwood instead.This system is water tight and very light on the trailer.After 22 years ,this sailtube looks almost new.The aluminum spiral pipe holds my main , genoa,storm jib,boom,hot stick,crane parts to raise mast and the entire rudder assemble nice and tight.Oh,extra battens and original tiller too.
Check with your local sheet metal production shop to see if they form their own spiral and possibly have one sitting around to sale you along with the caps.
Bill 404 21SE 😎

Found an aluminum 12" pipe laying in the grass at a lumber yard! $10 and haul it away! My scavenger hunt continues for other items LOL

I picked up a 13 or 14" diameter section of PVC piping, nearly 20' long, from a construction site, where they were installing new sewers. It had one end cracked after being hit by a piece of machinery. Got it for 2 cold Grolsch. They are about 1/4" thick material, but cut easily with a skillsaw or jig saw.
I got an end cap that fits perfectly. The downside to this material is that it is quite heavy. It would be difficult to break open, if security is an issue.
I never ended up using it, as i decided it was just as easy to store the sail in the garage, & I leave the boat fully rigged, blocks, tiller extension etc. Only the main sail comes off at days end.

I had access to some 12'' sewer pipe, PVC. Got the pipe for nada. The end caps were pretty expensive. we paid 80 bucks for one. OUCH.

I love my 10 foot pipe bomb/sail tube. Drilled a hole through the cap and pipe, and used a large push pin. It's heavy but not as heavy as the rotted 2x4 framed wood box that was riddled with bugs and rot.

If anyone is in the Atlanta area and is looking for a 10' section of 12" PVC pipe, please let me know. I had to buy a 20' stick and have 10' left over. PM me if you are interested.