DIY Homemade Catamaran Sailboat from PVC pipe

RebelCat 2 - Radical Departure in Design

Back in the USA, I decided to scale up the RebelCat design to do some serious sailing.

Shelter where I build RebelCat 2 near Phoenix, AZ

Humble beginnings. I rented a corner in a yard behind an auto repair, seven miles from my father's house, where I lived. I rode my bike six days a week in 110-degree Mesa, Arizona heat to get here, worked all day, then rode home. That was my routine for two months.

The shelter includes a workbench, drill press and a canopy I stitched from cheap material.

In the back you can see the 12-inch PVC pipe, 2 x 2 inch aluminum pipe, plywood and foam insulation boards.

There were far too many steps in the construction to show here, so I've selected a few to show the progression and the challenges.

Stuffing pipe and reducers with foam discs

PIP PVC pipe is thinwall and is quite flexible. It can also be punctured during a crash and fill with water. I decided to make this cat unsinkable. I stuffed the entire pontoons and cones with foam insulation. A mouse would not have found room to nest in there - packed solid from nose to tail.

The four things in the front are PVC reducers, to reduce the diameter of the pipe from 12 to 10 inches, because I could not find traffic cones larger than 10 inches. But the reducers are not smooth, they reduce sharply, so I made a paste from sawdust and white glue and filled in the space to make the nose hydrodynamic. Bad choice, as it turned out. The paste did dry and worked fine, but small nicks in the waterproof coating allowed water in and the paste soaked away. That was long after it was turned into a raft and set loose on a pond in Illinois.

Thick plywood sheet cut into many pieces for the cat

Plywood cut to make all the parts I needed from 3/4 ply. In the foreground is the centerboard and the rudder stock, then behind will be the rudder, the transom and I can't remember the others.

Frame assembled showing rudder and centerboard

Here the frame is complete and the rudder and centerboard are visible. Both will swing up for shallow water and beaching.

Making the mainsail in a carport at home

This is the main sail, and it is huge. My first real Dacron sail project. I studied sailmaking and jumped into this with no hesitation. Since I was renting space for the boat construction, I worked at home on the sails on Sunday, when the auto shop was closed. So, yes, I was working seven days a week to get this boat done. If you work in 110-degree heat all day, sunrise to sunset, you want to finish the job as soon as possible.

I think the mainsail is eight feet across the foot and maybe 22 feet tall. Working with real sailcloth is like trying to sew cardboard. It lays flat with no difficulty, but trying to get it through the sewing machine is fun. Rolling it up made it easier, as you can see below.

Sewing mainsail on machine

Here I'm sewing a reef point on the jib. You may say, "But jibs don't have reefpoints". Mine does. If you look at the next photo, you can see that the entire lower triangle marked off by this white polyester tape can be rolled up and tied to the sail, reducing its area. There is a second cringle (grommet for attaching a sheet, or rope) right where the white line meets the blue. I never saw it done, but I love to experiment. I also never reefed the jib, so I can't say how well it would work.

 Both sails up in my backyard

During the last stages of construction, I moved the whole operation to my father's backyard, now that the noisy part was done. The white cloths covering the blue reducers prevent the PVC from getting soft in the incredible heat of the sun. I made a note not to paint PVC dark colors again. I later sprayed the tops white to prevent them from melting. This is Arizona.

Sitting on plywood box seats and storage

An early phase of the construction. I had planned to have two storage boxes that double as seats on the sides. I made them and they were looking good.

Sealing boxes with resin

Then I sealed them with boat resin. However, this was to become a disaster, as the resin never cured. The tube of catalyst had been taped on the cover of the can and it burst in the heat, leaking catalyst into the can through the sealed lid. So the resin looked a little odd, but I used it anyway. Bad move. It simply never cured and smelled like, well, resin for months.

I worked on everything else, hoping the resin would cure - it didn't. So in the later stages I had to find a replacement for the two boxes. I chose large ice chests, huge ones. Four of them. Great storage, not great seats.

Adapting ice chests to replace the seat boxes

Sure, they look impressive, but as far as sturdy parts of a boat that is going to be treated roughly, they didn't qualify.

Fortunately, I didn't drill holes in them to mount them, so later I cleaned them really well and returned them to the store.

Spray-painting cones blue

Orange cones are okay for the road, but I wanted them to match the sails, so I used fabric paint. It bonds well and is heat resistant. No problem leaving them in the sun. I later discovered Krylon Fusion which works much better for plastic and PVC.

Assembly on lake shore

First test on Lake Roosevelt, in the mountains SE of Phoenix. At this point the boat is completed, and I'm assembling the parts which I have brought in a U-Haul truck.

What I don't see at this point is the fatal flaw in the pontoon supports - the blue steel 'L' things that hold the frame together and are bolted to the pontoons. We got in the water, put a little weight on the boat, and the pontoons folded up - the metal simply didn't hold. It was an oversight, it wasted a day, but it was easily remedied.

Welding pontoon supports

I welded the 'L' pieces into triangles, by adding a piece of steel to close the 'L'.

All pontoon support braces done

After all were welded and tested with a hammer for strength, I painted them blue.

RebelCat 2 sailing Lake Sajuaro

The second test was on Lake Sajuaro, and the boat sailed well. At first there was no wind, so my father and I are rowing around waiting for it. He got bored and went ashore, and a friend joined me. Then we got some nice wind and sailed like crazy across the lake. Some powerboat owners probably couldn't handle having a sailboat in 'their' lake. Two of them came by pretty close at great speed, creating wakes about three feet high coming from both sides. The boat rocked violently, the heavy mast jerked from side to side and a stay yanked one pontoon loose from the frame. The right side of the boat dipped into the water, but it stopped when the two huge ice chests on that side touched the water. The whole side of the boat was supported by those coolers!

A kind gentleman in a motorboat came and towed us to shore, where I took the cat apart. I realized that my radical departure from the original design was not successful, and I decided that the next RebelCat would follow the prototype more closely.

Pontoons of RebelCat 2 made into a raft for a pond

RebelCat 2 lives on as a raft on a pond in Illinois! Most of the cat was recycled into other projects, including RebelCat 4, book shelves, and pieces of aluminum made it into RebelCat 5.

RebelCat 2 taught me a lot about what does and does not work on this kind of catamaran, so in that respect is was a success. The RebelCats to follow benefitted greatly from this experiment.

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