From: Bedfordshire UK
I agree with the proposal, with the exception of submarines where a unit could be considered as several boats, where individual boats return to port and others take their place, to maintain the strength of the unit.
I have no immediate answer, apart from to note the later use of more capable replenishment, that would allow units to remain in sea areas for more turns than during the early war period. The USN developed this into an art, which should allow them to remain at sea for longer.
Without replenishment, or nearby port, a unit should lose efficiently, in that ships without fuel become unable to function, but rather than accumulating hits it should happen at the limit of range, with a one-off drop (but never to zero without combat). Players would be forced to return now vulnerable units to port, to avoid potential destruction.
"We have to go from where we are, not from where we would like to be" - me