Call to knowledge: anyone knows a good IP68 waterproof servo motor?

Hi folks,
I am looking for a pair of waterproof servos, but they need to be at least IP68 since the application is a submarine that will be underwater for a while.

It's hard to find, most I found online are IP67. Its voltage range can be between 5 and 12V.

Any idea? thanks a lot.

Mr Google knows ...

"Waterproof" means almost nothing, certainly doesn't imply its suitable for a submarine, for which IP68 + a maximum depth is needed.