Submarine cables are only suitable for use under water, that is what they are made for.
Without breathing, the world record is 22min With air bottles (scuba diver) or in a submarine you can of course stay longer. In a submarine when you have enough supplies, you can stay virtually forever under water.
A submarine is only used under water.
The submarine is under water.
For modern nuclear subs, they could theoretically stay under indefinitely. Of course, there's a crew which has to eat and bathe, and food and toiletries do eventually run out.
The vessel is a submarine.
Submarine.
Yes they can!
it is a under water earthquake
In war a submarine can hide under the water and attack without being seen.
A submarine is a vessel that can travel both on the surface and under the water.
A submarine is a sea-going vessel, both on the surface and under the water.