DIY Raspberry Pi Shipwreck Hunting ROV

So one day a while back I watched the movie “Spare Parts”. It was about a group of high school kids who built an ROV for competition and beat MIT. After seeing this movie, I thought that it would be fun to build my own ROV, so I searched online and found the MIT SeaPerch. This was a cheap beginner level ROV to build, but you really couldn’t explore anywhere with it. I needed to build something better. I then stumbled upon BlueRobotics. Then after some research I decided to build a ROV using a BlueRobotics Enclosure and a Raspberry pi as the brain for shipwreck hunting in the great lakes. I have decided to code and build everything (excluding the enclosure) myself. I am going to use a fathom s board to communicate over serial and to send video across a 200m cat5 cable. I am planning on having a three fingered manipulator for item recovery and a GPS buoy ( I will explain later.) if it works. I will be using 4 DIY thrusters, 2 for forward/turning, 1 for vertical and 1 for horisontal. I will use a Raspberry Pi camera ( or something like it) for live feed and a gopro for recording. I will post more as I progress through the project further.

GPS Buoy Idea:
So basically I am going to have a buoy attached to my ROV that has a GPS on it. This buoy will be able to be retracted if needed. The GPS will send coordinates over cable to the ROV to pinpoint the ROV’s position. Then when I have the position I will record it to remember where whatever the ROV was looking at was. I would us the UGPS Blue Robotics sells, but it is way to expensive for my needs. What are some flaws I may have overlooked for this idea?

I am planning on using my ROV as an underwater item recovery service as well as shipwreck hunting. Is there any legal issues with using BR products on my ROV and making money with it?

If you are shipwreck hunting, become familiar with Abandoned Shipwreck Act of 1987: Text of S. 858 (100th): Abandoned Shipwreck Act of 1987 (Passed Congress version) -

That is the overarching law, but state laws will be more strict on what you can do. Generally, finding and filming wrecks is fine. Touching and disturbing wrecks is illegal. For the state of California, anything older than 50 years is considered a historic wreck.