McNarney ordered the bombers to attack hostile submarines "wherever they may be operating."

The Lesser and Greater Antilles helped bar entry by hostile submarines.

Unseen was a very quiet, possibly hostile submarine, and she could be within 10 miles of him.

The cause for their concern was clear--symbols indicating hostile submarines and subsurface contacts cluttered the large blue display.

Men trained on her decks played an important role in the successful contest for the Atlantic with hostile submarines carried out by the escort carrier groups.

If he were close enough, he could see a hostile submarine.

As opposed to a torpedo (after sonar calls "torpedo in the water") which is launched by a hostile submarine.

Of course, there were plenty of live opportunities to hunt for hostile submarines.

When a hostile submarine is detected, the crippled ship has to flee at its best speed.

The sonar mounted in the nose is activated upon entering the water, searching for hostile submarines.