The German leaders decided to use submarines.

He asked: "What if the Germans were to use submarines against commerce without restriction?"

The narcos use jets and helicopters, speedboats, and even submarines.

When the Danish Navy announced that they would stop using submarines completely in the summer of 2004, the whole Viking project died out.

Prior to the recent change by the U.S., no nation using nuclear submarines permitted women to serve on board.

Several of the trials were intended to established tactical methods of using submarines in warfare.

A spreader of good will, the ambassador has even suggested using decommissioned nuclear submarines to transport cargo under the ice.

At sea, the war focused on using aircraft carriers and submarines.

The Italians were also involved but achieved their greatest success using midget submarines and human torpedoes.

The United States, like other military powers, has long asserted its right under international law to patrol the high seas using ships, planes and submarines.