From: Oxford, United Kingdom
It seems to me that navies are basically a bit useless at preventing invasions (taking defending against a classic Sea Lion as an example, or an invasion of Sicily from Tunisia/Malta), at least ones where the invader can move their amphibious transports from their origin port to the unloading hex in one turn. As there is usually no period where the invader's transports are in open sea for counter-attack during the defender's turn (because they can unload in the same turn that they move to the unloading hex, unless they get surprised by a sub or something like that), the only opportunities to damage/destroy the transports would seem to be:
a) By attacking them in port on the turn they embark, with ships and/or air (though this seems relatively ineffective and means leaving your navy and/or airforce in very close proximity, which potentially leaves them prone to counterattack by enemy subs/air etc.
b) If they try to invade next to a port hex in which you have a ship, then that ship gets a shot at the transport - BUT this is risky for the defender, as leaving a ship in port in range of enemy bombers is likely to result in serious damage to the ship.
c) Block all routes to potential invasion hexes with naval units at sea - even more non-viable than b) - ships not in port are likely to be seriously damaged or sunk by enemy bombers, subs etc., also, if these units are spotted (easy to do with air), there is no surprise for transports and they can either try to move around them or even through them (though would risk taking damage and losing AP), they don't block completely.
d) Try to surprise transports by using numbers of submerged subs - less risky than c), but the transport would actually have to accidentally enter the exact hex that the sub is in to be surprised by it and get attacked and the invader could possibly sweep for subs with destroyers/MTs on the invasion turn, so that they could be avoided (though risky to the DD). Also the number of available subs (for the allies, anyway) is quite limited.
NB: one thing the defender's ships can be quite useful for is to scout the potential invasion jump-off ports/cities each turn to see if they contain any enemy transports, so that you get some warning, though this too can be risky if the port ends up containing a sub or enemy warship and you suffer a surprise attack!
Have I missed anything? Or are there any better ways of using your navies to defend or otherwise assist against invasions that I've missed?
The naval aspect of Strategic Command is probably the one I'm finding hardest to master, don't think I'm the only one, though!
< Message edited by oxford_guy -- 9/21/2017 12:49:01 PM >