Under Pelagos > Prototypes > technologies.lua > line 684, the overseas-energy-distribution technology does not exist if "Enable floating electric pole" setting is disabled in Cargo Ships. While it is enabled by default, I disabled it because Planetaris Unbounded: Arig adds a power pole that functions very similarly, placeable on ocean-like tiles

I will check it out

The good thing is
it will be fixed in 0.15.0

The bad thing is
planetaris electric pole breaks balance on pelagos and few other places so it's disabled on pelagos deep sea (still can be placed on shallow water).
And I contacted sven with this issue. I did not checked this pole before so i noticed it now.
The poles generally are complementary to each other in terms of use so I recomend to keep both of them
Arig one feels just right for connecting machines on shallow water while cargo ship one works best on long distances

Thing that is breaking balance is electric grid
Cargo ship pole don't have it so you can't connect electric machines on sea
pump is electric machine. and powering pump allow for long pipelines making ships less usefull

Ahh, that makes a lot of sense, and very good to know, thanks!