[krasin]

>The way around that is to use expensive hermetically sealed connectors that are designed to operate underwater. Each side of those will cost a few hundred USD for boring round connectors.

In this respect, I highly recommend Cobalt series of connectors from Blue Trail Engineering: https://www.bluetrailengineering.com/professional-products - they cost "just" tens of dollars each and are very good (I used them); quite popular with ROV community.

[montag]

What does ROV stand for?

[krasin]

> What does ROV stand for?

My apologies for an acronym. It's Remote operated underwater vehicle: https://en.wikipedia.org/wiki/Remotely_operated_underwater_v... (a small submarine, usually, with a long thin tether)

[jvanderbot]

I'm guessing remote operated vehicle - e.g., remote controlled submarines.