Underwater ROV

Step 3 Thrusters

One of the most important features of an ROV is movement. I found that most people use marine bilge pumps as a means of thrust. BIlge pumps have many advantages. They are meant to be submerged, they are fairly powerful and they are easy to add to an existing ROV. Most use them in their current configuration, but I opted to use propellers to increase thrust. I followed the instructions at Homebuilt ROVs. In the How To sections, he has instructions on converting a bilge pump to use a prop. The propellers came from Harbor Models, they have a good selection of plastic and some nice brass props, with many different sizes.

I used 4 Rule 1100 GPH bilge Pumps, 2 for forward, backward and turning, and 2 for up and down.

Step 1: Cut off all of the white housing of the bilge pump, but be careful not to cut into the red motor housing

Step 2: Use a screwdriver to pry off the impeller, the blue thing to expose the motor shaft.

Step 3: I use a prop adapter for an airplane to attach the propeller to the shaft. It has a set screw, and I just tightened the nut against the threaded hub on the prop to lock it in position. I had to re-thread the prop adapter because it was a little too big. As a extra precaution, i used thread locker to seal the assembly together.

Since the threads did not line up, I was forced to re-tap the prop adapter. Although it seemed straightforward, it took considerable time to do it correctly.