Defence Diving School

Divers from the Defence Diving School The Defence Diving School is a Joint Service establishment. It was set up in 1995 from the Minewarfare and Diving Department at the School of Maritime Operations (SMOPS) and the Royal Engineer Diving Establishment (REDE) and formed in a purpose built facility based at Horsea Island following the closure of HMS Nelson, Gunwharf Site, (formerly HMS Vernon) in Portsmouth.

The School is an independent command in the Naval Recruiting and Training Agency (NRTA). Command of the School alternates between a RN Commander and a RE Lieutenant Colonel who is accountable to the Commodore of HMS Excellent. This is because the School is also a lodger unit of HMS Excellent, as Horsea Island is part of the establishment's real estate, and the Commodore provides support in a number of areas to the School.

The School's primary purpose is to train divers for service in both the Fleet and Field Army. The facilities at Horsea Island are excellent for the task and include a 1000m lake with a number of jetties, a 5m dive tank, Recompression Chambers, an Underwater Engineering Facility, a Specialist Diving Clothing Store and Laundry, Workshops and a variety of Classrooms, Conference Rooms, Catering and Showering Facilities. There is also a boats facility based at HMS Excellent, Whale Island for diving in the Dockyard and Solent. Diving in deeper water is carried out at Portland, Wyke Regis, Plymouth and from a Fleet Diving Tender in the Western Isles.

Horsea Lake had been used for diver training for a number of years prior to the formation of the School. The history of the lake itself dates back to the 1880s when Horsea was selected as the site for a non-tidal testing range for a new and developing weapon system, the torpedo. This entailed filling in the gap between Great and Little Horsea Islands to create an 800 yard Lake; a task carried out by convicts using chalk and marl from Paulsgrove chalk-pit. The Army built and operated a railway to transport the chalk. Horsea Torpedo Range was officially opened in March 1889. Improvements in the efficiency of the torpedo led to the Lake being extended to 1115 yards in 1905. Further developments in range meant that Horsea Island's importance for torpedo trials progressively declined; although trials were still conducted in the Lake during the 2nd World War.

Following the arrival of wireless telegraphy, Horsea Island became the first of three high-powered shore wireless stations for the Royal Navy in March 1909. The equipment was regularly updated and Horsea remained in operational use as a Wireless/Telegraphy Station until the 1960s. From 1922 to 1932 experiments were conducted in the Lake with model submarines. In 1942 the early training for "chariots" was carried out at Horsea. In 1944 Landing Craft were repaired and refitted for the Normandy landings.