Torpedo Belt - The Problem

The Problem

Armoured warships (dreadnought battleships, armoured cruisers and later light and heavy cruisers) of the early 20th century carried their main protective armour above the waterline – the "main belt" – which was intended to stop flat-trajectory gunfire from piercing the hull. Below the belt, the armour generally tapered away, to reduce overall weight. This, however, makes a ship vulnerable to hits below the waterline from torpedoes; and the occasional large-calibre shell. Extending the belt downwards is impractical, since this increases displacement, which increases draught and can result in reduced speed, and decreasing seaworthiness.