Foolish companies in alternating current don't use maps of the sea (7)
I believe the answer is:
oceanic
'of the sea' is the definition.
(I've seen this in another clue)
'foolish companies in alternating current don't use maps' is the wordplay.
I cannot really understand how this works, but
'current' could be 'ocean' (ocean current is a kind of current) and 'ocean' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for oceanic that I've seen before include "Pelagic" , "vast waves?" , "Like the main" , "Relating to large areas of water" , "Cocaine (anag)" .)