Submarines mines were divided into two; offensive mines and defensive mines of these defensive mines were considered the most reliable.

Defensive mines included; mechanical, electro-contact and observation mines, of these the observation mine was the weapon of choice as they could lie absolutely safe and inert under the bottoms of friendly ships, but became a most effective barrier to the enemy.

Under the heading of offensive weapons electro-contact, mechanical mines, outrigger torpedoes, creeps, sweeps, counter mines and explosive charges were considered. A brief history of torpedo warfare followed.

Accession No.1618