@wittmann:
Afternoon Suprtramp.
Yes it can. Only Navy blocks naval movement(or a Strait of course!).
An island is a separate territory, yes.
With the exception of Subs and Transports, which cannot block enemy movement by themselves.
If a sub attacks a lone transport outside an enemy island with an airbase and fighters, is the transport automatically sunk, or does scrambling do anything to prevent that?
The fighters can scramble. However, since there is no defending destroyer, they can’t hit the sub. As a result, the transport will be sunk anyway.