Water Worlds oh my..

[C57D]

Maybe the oceans are an earlier "final frontier" ?
With 70% of the world's surface and trenches up 11 km deep, I would imagine it would be a fertile setting for near future scifi adventures. A few human mining colonies / research bases with a bit of real world intrigue, a bit of HP Lovecraftian ancient submerged civillisations to uncover, and a few still with us. Super sea dragonish beasties, sunken shipwrecks (and what sunk them!!) etc etc.
Maybe "landing parties" go outside inside super pressure proof armoured mini-mechs??

 

[MAGolding]

I sort of have an idea for a Star Trek/Voyage to the Bottom of the Sea/Seaquest combination called something like Voyager to the Bottom of the Seas or maybe Water Trek. It is about a starship Voyager that usually travels to ocean planets or to the oceans of planets like Earth.

The trouble with submarine science fiction is that the oceans of a single planet are usually limited in their potential for sea monsters, undersea civilizations, hidden alien Bases, mad scientist labs, and other science fictional story elements, just as the land areas of a single planet are likely to have limited potential for science fiction stories. But the land or ocean areas of tens, hundreds, and thousands of planets together are likely to a lot of total potential for science fictional stories.

So in thus future civilization some starships travel to the land areas of Earthlike planets, other starships travel to the land areas of various non Earth like planets, and other starships like Voyager travel to the oceans of various planets.

I note that there are about half a dozen icy and airless moons in our outer solar system alone that might possibly have inner oceans, possibly having life, beneath their icy crusts. Titan might even have both strange alien life on its surface and an entirely separate ecosystem of strange alien life in an inner ocean.

Getting to the inner oceans beneath many miles of ice would be very hard, but maybe it would be easy for a society that has FTL starships.

And of course some alien planets might have oceans of molten lead or sulfur, or ammonia, or methane that the Voyager might be able to travel in or under.

As for using phasers underwater, it isn't the salt that would be a problem, but the density of the water. Firing ray guns underwater would be likely to boil the ship.