I thought I would share my home built towed camera sled since it shares much of the same tech as an ROV, minus the propulsion system. In fact, this sled morphed from an ROV, into the towed sled since I needed to be able to operate deeper than a simple ROV was going to allow.
The camera is towed (very slowly) from the boat using an electric winch with slip-ring, on 1500’ of umbilical. The umbilical is made up of a cable with 2 pairs, and 7/64 Amsteel Blue rope. One pair feeds analog video up to the boat, and the other is used for RS-485 communications to control the cameras, power, and lights, as well as to send depth, temperature and other information. The Amsteel rope is needed because the camera sled weighs in at about 80 lbs in air (probably less than half that in water).
The camera is self powered by a 30 amp/hour NiMH battery back, so the umbilical can be kept as small in diameter as possible. I get about 1 hour run time per battery pack with all of the main LED lights on.
For my application, the lights consume 90% of the battery power. I run a ton of LED lights since I typically use the camera at depths over 300’, and here on the west coast its pretty much dark at that depth, so lots of light is needed for good quality footage. I record high definition video and stills using a few GoPro cameras, and the live video that is fed to the boat is just low resolution analog cameras, only used for navigation. I can switch between 4 different live cameras depending on what view I need.
I have spent a lot of time getting the lighting and stability of this camera sled correct. It is still a work in progress. My footage is all from Southern California in water ranging from ~170’ to 1400’. Visit my youtube site for more footage. I add new video every couple of months usually. https://www.youtube.com/user/NPerry8051/videos
Hope you enjoy the footage!