"An enemy submarine base so near our own land!"

On 29 June, she sighted an enemy submarine but was unable to close.

U-66 was able to cast off at a moment's notice to attack an enemy submarine.

"You mean it's possible there actually could be an enemy submarine, lurking off our coast?"

We don't have a clue why an enemy submarine could sound like her.

It's not often you find an enemy submarine on the surface with its pants down like this one.

Two possible enemy submarines were astride his course to the ice.

The next evening, she attempted to close an enemy submarine but lost contact with the target.

They could also say just where in the water an enemy submarine hid.

The military is having trouble following the course of the enemy submarine.