Hi, robot update. I’m working on an ROV right now, and I am wondering are 12v enough to propel something through the water?
Thanks- Hengineer
It’s less about the voltage and more about the total power and the method of propulsion. For example, take a look at BlueROV thrusters which operate at 7-20 V:
ex: https://www.robotshop.com/en/t200-thruster-bluerov2-spare-cw-propeller-w-penetrator-cable.html
Got that, thanks! also, do you have any suggestions on an underwater camera? I thought about doing an endoscope, but if I ever expanded the wire connected to it, I would have to buy a new endoscope. any suggestions? Thanks- hengineer
Normally the choice of camera depends on the quality of the image, and as such, manufacturers tend to make camera enclosures rather than waterproof cameras. Ex:
GoPro Hero5 and above are waterproof up to 33 feet (10m) and the waterproof case pushes this up to 197’ (60m). Image and video quality are really good. However, if you want a live image, you’d need to drill the case to add a waterproof connector.
Aside from that, don’t know of any specific models to suggest.
UPDATE
can you please recommend a cheap camera for circuits? I want to place the cheap camera into something like you sent above, therefore saving money on an underwater camera and also getting a live image.
p. s. I’m not super worried about the quality of the camera, just want a live image. 
Not sure what you mean “for circuits”. Having a microcontroller handle a live video image is not easy. The main issue is having the power or means to send the image to the surface. For example, BlueRobotics offers a pair of interface boards for high speed long-distance Ethernet.
Cameras (the choice of which will depend on your needs and what you want to connect it to).