If you have a raft/inflatable boat and an old weedwacker, this is just for you. One afternoon I was so bored so I was thinking and thinking and my mind looked like this: Raft + Weedwacker = Never row or paddle again! So I went into the garage and started right away.
I had a ton of things laying around and so I didn't need to buy anything so I spent $0 on this work of art.
-Raft or Other Vessels
-Bits of Plastic or Washers
-Various Sized Screws, Bolts, and Nuts
-Rope and Rubber Bands
-90-Degree Angle Bracket
-A Sheet of Plastic or a Boat Rudder
-A Ton of Boredom
Step 1: Propeller Assembly
Blow up the raft and just check around and see what anchors/ties it has and what you're going to be working with.
Take the head off the weedwacker to expose just the end. I used a propeller from an old CPU fan and drilled a hole in the center. There was a gap left on the exposed shaft so I took a 1/2" cylinder of plastic and drilled the right size hole in it. You could also just stack a bunch of washers. Put it on the shaft, then the propeller, then screw the end back on.
Step 2: Engine Mount
To mount the engine on the raft, I cut a rectangle custom to my raft and to prevent it from poking my raft, I put a piece of heavy duty water resistant ram board (which I will need to replace eventually but I wanted to move on so) and then I used rubber bands to secure it to the plywood because I was going fast.
Step 3: Raft
My raft came with some rope so I tied it onto these big loops on either side to hold the mount on the raft. Then I put the plywood on the back to see how much rope I needed.
Step 4: Securing the Propeller Assembly to the Mount
The weedwacker I have has an adjustable handle that I repositioned so that it would aid in securing the shaft to the plywood. Then I marked 4 holes in the plywood and drilled them. I then got the 4 zip ties and put two for each set of holes and they are placed so that the handle can move so the prop can be lifted out of the water.
Step 5: Rudder
I had a piece of flat plastic that I cut a nice rudder shape out of and screwed it onto the 90-degree angle bracket and then attached the rudder assembly to a pre-existing hole in the shaft.
Step 6: Finishing Touches
For convenience, I took the engine off the shaft while building this and I reattached it at the very end. I also thought about painting some things later. Take the rope that is tied to the raft and wrap/tie it to the shaft of the engine to hold it on the raft and BOOM you have the best homemade motorboat ever.
Step 7: Hit the Lake
Since it rained the evening I started/finished, I haven't actually tried it in the water but it does fire up and spin REALLY FAST which is basically the only thing weedwackers are good at. But take your boat to a big body of water and float out to where the water is deep enough that it won't ruin the prop. I set the shaft handle really loose so I can turn the shaft in the handle and, as a result, the propeller turns in the water and the rudder makes the boat turn whatever way you want. Pictures and videos of me either having fun or sinking will be here ASAP.
VOTE FOR ME IN THE WATER CONTEST!!!