What should I do?

[scott_c2911]

Im in grid BF43 and its 1100 on a November morning in 1943. Ive intercepted a submarine hydrophone contact only to discover its one of ours.
Immediately on surfacing to greet our new friend we spot a Catilina coming in to attack the friendly. We immediately man the guns and we manage to shoot him down. We took moderate hull damage and a little flooding defending the friendly who seemed unable to dive. An hour later 2 Mosquitos move in on us. I dive and the friendly does not confirming my suspicions so I resurface to continue defending the friendly who has not responded to repeated hails. We shoot them down between us.
Another Catalina arrives on the scene an hour later and attacks the friendly. Again we took damage forward after he swung round to spray us with machine gun fire. We succeeded in shooting him down too. Another attack is surely on its way. Hull integrity is 85% and I am low on ammo. What should I do? This is a bit of a no win situatiion.