Have you shot at the Akagi both times?
Edit: Here are a couple of pix from a test mission I just did:
so the torpedoes do blow up just fine, and no crash
and:
so the ship takes damage and sinks. So the boat, the torpedoes and the target are all fine. I'll dig through a few more things, and then try to match your mod load and try the run again in the Campaign. I also have to check the Sargo out of Cavite just yet...