This will be a quick one.
For a few weeks I've been working on the general plan for the ROV, and demoing various strategies for collecting video and temperature data, and sending signals to it from a computer. Recently, I though, I moved on to working on the thrusters. These are ducted propellers which propel the ROV through the water.
This kind of design is pretty complicated. The shape of a propeller isn't easy to calculate or just guess, and propellers aren't easy to build either. Fortunately, there has been a lot of open-source development on other projects, which will likely be the topic of my next ROV update.
Based on what others have found, I purchased the following propeller:
I also bought a motor to drive it. The next step is to buy an electronic speed controller (ESC) that will deliver power to the motor as commanded by and arduino micro controller. Before I buy the ESC, though, I need to make some decisions about what kind of battery this is going to use. I have some ideas based on other projects, but I'd like to consider a few options before I make a final decision.
So that's the plan right now: select a battery, then start building the thrusters, and once I can control them from a laptop, build them into a waterproof frame and attach a housing for the electronics.