I have exactly ZERO experience with ROVs but I am SCUBA certified and have a degree in Physics (from 1991 and I am a software developer by trade but that is another story.) I just read the article in the May/June 2016 Popular Science and was intrigued by this project. When I read about the max depth I assumed that it was because of pressure causing leaks/crushing and immediately had an idea. I think it should work but you folks with real world experience may know a myriad of reasons why it won’t.
The biggest problem for manned submersibles is that the humans inside need to breathe air (a gas) which is massively compressible so the structure has to withstand the crushing pressure of the water outside while allowing the air pressure inside to remain “suitable for human consumption.”
Unmanned submersibles don’t have to worry about pesky “occupants” but they do still have to protect their contents (electronics, etc) from the nasty water outside.
My proposal, fill the “empty” spaces in the ROV with liquid. “Andrew, you knucklehead, then you are going to ruin the electronics before you even put the ROV in the water.” Ah, but what if you use the same dielectric (non-conductive) mineral oil that über-gamers recently started using to immerse their gaming PCs to cool them or that has been used in transformers (of the voltage conversion type, not the Saturday morning cartoon type) for years?
Anyone have experience with something like this and can explain why it wouldn’t work? The only issue would be that you would have to get as close as possible to every last bit of air out of the spaces because any bubble could lead to crushing. However, making the “skin” of the ROV slightly less brittle would allow it to flex without cracking to accommodate minuscule bubbles (think fractions of a grain of rice) that might hide in some of the components inside the ROV.
I searched for dielectric in these forums but only found references to using dielectric grease for connectors.