Find me under the sea

We didn’t know a U boat was on our tail until the torpedoes hit our ship.
Some of us made it to the lifeboard.
The captain handed me his hat and jacket.
“Lie to them,” he said.
The Germans took us aboard, and they treated me well, good food and wine.
I gave them inflated numbers of men, ships, and weapons.
The other men were kept under lock and key.
But not me.
I had the run of the ship.
Navigation, radio room… and the torpedo room.
You’ll find us on the bottom, I whisper, and set off a warhead.