Torpedo classes and diameters
Torpedoes are launched several ways:
From a torpedo tube mounted either in a trainable deck
mount (common in destroyers), or fixed above or below the
waterline of a surface vessel (as in cruisers,
battleships, and armed merchant cruisers) or submarine.
Early submarines, and some torpedo boats (such as the
U.S. World War II PT boats, which used the Mark 13
aircraft torpedo) used deck-mounted "drop
collars", which simply relied on gravity.
From shackles aboard low-flying aircraft or helicopters.