Can you exert af ship resource for DRM when the warship attacks you in the first step of combat?
Also I read as you get -1 if warships are revealed not per war ship.
Can you help clarify?
It is a -1 DRM only, for revealed warship(s) present -- note, if the only revealed warship is being attacked, there is no penalty at all. There is an optional rule (Imperialist Naval Coordination) that DOES penalize PER warship.