Underwater Warfare

A brief history of the development of Underwater Warfare

The idea to make a stealthy underwater attack on ships, believed to be safely anchored in harbour, has roots in the Siege of Tyre in 333BC when Alexander the Great employed divers to destroy boom defences.


The great Leonardo da Vinci drew divers and submarines but the real breakthrough came with the production of a working submarine at the end of the 19th Century.

Two ingenious Italians Raffaele Rossetti and Raffaele Paolucci produced the Mignatta (Leech) a 4.5m bronze compressed air torpedo with hand holds. In a specially designed a flexible diving suit the two men entered Pola harbour and sank the Austrian battleship”Viribus Unitis”.

This great achievement inspired two young naval engineers in 1935 to develop a submersible that could be ridden through the water.

The Siluri Lenta Corsa (Slow Speed Torpedo) was nickname Maiale (pig) by the Italian operators because of its awful handling characteristics.

War in Europe seemed inevitable consequently in 1939 the Italian Navy implemented the formation of a special underwater unit as part of the feared Decima Flottiglia Mas (Tenth Light Flotilla).

On 9 November 1941, two Italian machines entered Alexandria harbour and blew up HMS Valiant and HMS Queen Elizabeth.

Prime Minister Winston Churchill saw the potential of this small craft and the British unit was formed training on Loch Cairnbawn situated on the remote North West coast of Scotland.

The development of the re-breather set gave the divers an oxygen supply of 6 hours. The flexible Belloni diving suit allowed sufficient movement for the tasks below the water to be carried out.

For more information, Robert Hobson’s historical account “Chariots of War” can be purchased through our office.

Many strange small craft with an underwater capability were developed during the Second World War that led to the development of the British Welman (one man) and X craft (four man).

Another form of underwater warfare was the use of the Midget submarine once again pioneered by the Italian Navy in conjunction with the engineer Giovanni Caproni in 1933. Known as CA1 (two man) and CA2 (three man) they were delivered to the navy in 1938.

The Second World War led to the development of the British Welman (one man) X craft (four man)

The Germans developed the Neger (one man) Molch (one man) Biber (one man) Seehund (two man)

The Japanese Kaiten (one man) KoHyoteki (two Man) Koryu (five man)

A strange motorised submersible canoe was developed by the British in 1942 nicknamed “Sleeping Beauty

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