@Marshmallow:
Unless he brings a destroyer, he can’t force the enemy sub to participate in the defense. The amphibious assault then fails unless he brings a surface warship with a combat value. The presence of the sub, submerged or not, prevents the amphibious assault.
On the other hand, if his opponent lets the sub participate in the defense, then yeah, it can die.
I’m sorry but this is not true Marsh, a submerged sub will not stop the amphib. Look on page 18 of the Euro rule book (2nd edition). Under step 3 land combat first paragraph (I know this is a strange place for it because it took me a while to find it).
“If there was no sea battle, or the sea zone has been cleared of all defending enemy units except transports and submarines that submerged during the sea battle, and the attacker still has land units committed to the coastal territory, move all attacking and defending units to the battle strip and conduct combat……”
Maybe you are thinking about not being able to ignore subs with out escorting your tpts with a war ship, but it says war ship, not surface warship so you could use a sub to escort if you want to.