1. Wireless Telegraphy and the defeat of the U-Boat  1914-1918 "The Admiralty are not prepared to take any steps in regards to submarines, because this vessel is the weapon of the weaker nation. If, however, this vessel can be rendered practical, the nation which possesses it will cease to be weak, and will became really powerful. More than any other nation we should have to fear the attack of submarines." George Goschen, First Lord of the Admiralty, 1900 Early Holland class submarine

2. Naval Aircraft HMA 1”Mayfly” Wrecked before its first flight Discouraged further development

3. Wireless HMS Defiance Torpedo school Within two years of Jacksons experiments Wireless telegraphy was institutionalised into the Royal Navy

4. Submarines Sunk Ships which survived

5. Detection: Room 40 and the Y intercept stations Excellent intelligence on German submarines expected to be in the area sometimes including the submarines ID number and even the name of the captain. F. Thorpe May 1915: Room 40 was able to follow the track of a U-boat across the North Sea. December 1914: Room 40 well informed about the strength and general location of the U-boat Fleet

6. Convoys “Long range wireless signalling was essential to the effective control of a convoy, its main function being to provide a means by which a convoy could be diverted so as to avoid a locality in which enemy submarines were operating, …” Review of Trade position, Sept 1917 “During the whole war, except for a single occasion,..., no ship escorted by an airship was ever sunk.” Abbott (1989) p.4)

7. 16 th Sept 1918 SSZ.1 on patrol Spotted an Oil Spill and followed the track Called patrol boats to support which dropped depth charges on the target area destroying UB.103 Co-ordinated Attack 29 th Sept 1918 R.29 on patrol off the Northumberland Coast. Spotted an oil patch on the water and signalled a nearby destroyer HMS Ouse to join the attack. A second destroyer HMS Star also joined the attack sinking UB.115

8. Types of airborne Wireless Transmitters and Receivers Transmitters Type 12 Aircraft Set Type 50 Type 51 Type 52 – 40 watts Type 53 – 500 watts Type 54a – 200 watts Type 54b – 100 watts Receivers Type T Type Ta Type Tb Type Tc Type Td

9. The radio equipment in the Cranwell airships consisted of, [...], a type TC crystal receiver with a Brown’s Relay amplifier and a type 52B spark transmitter. The radio equipment of the Calshot flying-boats consisted of a thermionic valve receiver and a type 52B spark transmitter. The equipment of a wireless operator going on patrol... included... a close fitting leather helmet with attached brown’s adjustable diaphragm earphones, a large, accurate and waterproof patrol issue watch, an 8cell fully charged lead-acid accumulator,..., a lead weighted code book, and an Aldis lamp. Air Mechanic F. Thorpe Wireless operator on airships and flying boats Based at RNAS Calshot and RNAS Cranwell

10. Conclusions: The defeat of the U-boat threat in the First World War relied on a variety of technologies; some new some slightly older, combined with a new tactical approach. The use of aircraft as reconnaissance and weapons platforms The introduction of Convoys The use of W/T to re-rout convoys round suspected U-boat positions The use of W/T to co-ordinate attacks between ships and aircraft

11. There is still an enormous amount of research to be conducted on this topic. Following the War the efforts and results achieved by Room 40 were downplayed in order to hide the advances made in wireless direction finding and British Code Breaking. The Admiralty also downplayed the significance of the U-boat threat, not wishing to reveal how successful unrestricted submarine warfare was or how close it had come to defeating the Royal Navy. However

12. Marconi wireless operators often stayed at their posts transmitting and receiving messages even under fire. John McMillan: Wireless operator S.S. Wayfarer March 1915 The safety of the ship was “due to the promptness with which wireless enabled her to summon assistance.” Wireless room on a Cunard Liner