Thanks to everyone that helped with my other build log "1980 Outrigger with an Electric Outboard". You guys were a lot of help. I closed that build log. I am now going to build a "Predator" outrigger airboat. I have always wanted to build an outrigger and love how an RC airboat drives. First picture shows an outrigger airboat like I talking about. The 2nd picture shows what I have done so far. They are the tub sides. They are 1/8" plywood with 1/8" balsa doublers. (Blanket is making transom edge look jagged, they are cut straight). 3rd picture is a PDF file of the "Predator" outrigger.

Got the bulkheads (formers) cut. They are 1/8" plywood.

Bulkheads (formers) and transom are now glued in. I put in 2 extra formers (the little ones that go side to side) to make it a little more rigid. It still needs to be sanded. I forgot to drill hole through main former for wiring to go through. I will fix that.

The nose piece is now on, so are most of the balsa reinforcements (had to use square stock, hobby store was out of triangle stock). Bottom is skinned with 1/32" ply. This will be it for a couple of weeks, until I get supplies.

Rear sponsons are built and glued on boat. I had some sanding to do on one of the sponsons to get both sponsons even and square to the transom. Rudder arrived (it's not bolted on yet). Pictures are bad I know. I took them really fast because it started snowing.

She is looking good.

Thanks Kcal. I am building the hatch covers in a different way. It's 1 hatch cover from front to back. Hatch cover is thin clear plastic (a little thinner then the 1/32" plywood). Here is a close up picture. After I sand the front I will post a picture of the whole boat showing all of the hatch cover. The deck is not glued on yet.

Here it is with the clear hatch cover on. It's hard to see with all the glare. The deck is just taped down.

I changed the rear sponsons. I glued 1/32" plywood over them. I am trying to make it more of a flat bottom (remember this is going to be an airboat). I could have just taken rear sponsons off, but that would change the ride attitude of the boat (the transom would now be lower then it should be when on plane). Steering servo is also mounted. I am using a Hi-Tec HS-81 because that is what I already have.

Those rear sponsons look pretty tall, are the fronts that deep below the hull too?

Originally Posted by wparsons

Those rear sponsons look pretty tall, are the fronts that deep below the hull too?

Here is the PDF file, so you can look at it. I copied it so that the boat is 23 1/2" long. If you lay the boat on top of the plans, the rear sponson is 1/16" taller (below the bottom of the hull) then it should be and a little less then 1/16" longer (past the transom) then it should be. In the picture I agree, the rear sponson looks HUGE. Now let me ask you, should I make the front sponsons 1/16" bigger? Or is that difference little enough not to worry about?

I would make the fronts 1/16" taller (or just drill the holes so they sit 1/16" lower) to keep the hull flat. I didn't realize that the bottom curves up so much which is why the rears look so tall.

Now have the motor stand built. It is just sitting on the boat not glued on yet. I am planning on using a 9" prop. I am going to wait until I get the motor before I make motor mount "plate" and glue everything together. Inside of boat is sealed and painted. Boat is going to be white with green sponsons and green inside.

Originally Posted by wparsons

I would make the fronts 1/16" taller (or just drill the holes so they sit 1/16" lower) to keep the hull flat. I didn't realize that the bottom curves up so much which is why the rears look so tall.

The holes are already drilled in the tub, so I am going to drill holes 1/16" higher in the front sponsons, so they will sit lower. Thanks for the idea.

I like the green, good choice.