This is how to easily make a small sheet metal boat powered by a small electric motor and propeller. All it takes is a few simple steps and materials and you will have a working boat. I was inspired by a small electric powered racing boat I've seen driving at a lake, this is not as fast or as cool, but the concept was a cool thing to try to make.
Step 1: Materials
Sheet Metal Cutters
Soldering Iron and Solder
Sheet Metal Machine
Bucket of Water
Hot Glue Gun
3/32 inch welding Rod
1/4 inch screw
Step 2: Paper Cutout
Draw out the boat design onto a piece of paper so you don't waste metal trying to get it right. The sides will be 1 1/4 inches tall, the deck should be 4 inches wide, and bow to stern should be 8 inches. In the picture, each flap is 1/4 inch, and will be used later.
Optional: Fold the paper at the lines to make sure everywhere meets correctly, then tape it to hold the boat shape in place. Later you will need to take the tape off though. You can use this cutout, or find a similar one online, most shapes like this one will work for what your going to do.
Step 3: Metal Cutout
Trace the outline of the paper cutout onto sheet metal, this is very easy with a pencil, if you can't see the pencil, try a marker or scratch awl. When your done with this, cut out the plan which should give you this shape.
Step 4: Bend the Flaps
Using the right angle bender on the sheet metal machine, bend every 1/4 inch flap 90 degrees. For the flaps on the curve, you'll have to use pliers to get the right shape.
Step 5: Bend the Sides
Bend the two sides first, using either pliers or the bend part on the sheet metal machine. Then bend the back part with the flaps on it, making sure the 1/4 inch flaps end up on the inside. Spot weld the flaps to the sides, but any coating must first be sandblasted off before spot welding.
Step 6: Soldering and Spot Welding
Sandblast every joint your going to spot weld or sand blast, so all the creases, edges, back and front of flaps and outside corners. Spot weld the flaps to the deck of the boat, and spot weld the two front edges together. Now use the soldering iron to melt solder onto all open joints, so the whole area from the tip of the bow to where the sides are bent. Also solder the two back corners. If you don't have solder, you can use anything similar that will be able to seal the holes from water.
Step 7: Drilling Out the Shell and Placing It
Grab the 1/4 inch screw and saw off the threaded part and the head. Put the rest of the screw (about 3 inches long) into the lathe and drill out the center of the screw with a 7/64 inch drill bit. With a hand drill and a 1/4 inch bit, drill into the boat straight down, then slant the drill sideways to make an angled hole. Sandblast the screw and the area by the hole, then solder the screw into place in the hole, making sure one end of the screw sticks out slightly past the back of the boat. Make sure the 3/32 inch welding rod fits in the screw (shell) and spins fairly easily.
Step 8: Putting Together the Motor
The little grey electric motor will attach to the copper rod and then be stuck through the screw, so that when the motor runs, the rod doesn't wobble, and the propeller will turn smoothly, making the boat run right. Make sure that the rod reaches underwater so that when you attach the propeller, it hits the water and doesn't just spin in the air.
Step 9: Motor Stand
Get two 1 inch by 1 1/4 inch pieces of sheet metal, and bend the 1/4 inch flaps at a right angle. Sandblast the the two pieces then spot weld them to the boat deck to hold the motor in place. Hot glue the motor to those pieces so that it doesn't wobble when it runs. Cut the copper rod at the back of the boat so that the propeller doesn't hit the boat when it spins. To get the propeller on, you'll need to drill out the center of it with a 3/32 inch drill bit, then sand the end of the rod so it slides on and gets stuck in place on the rod.
Step 10: Testing the Motor
Connect the motor to a circuit with a power source to see if it will run correctly. If it does, put a battery in your boat, and when you want to drive it, connect the wires.
martinhui made it!