About
The Diving Museum occupies No. 2 Battery on Stokes Bay Road at Gosport, a Victorian coastal artillery battery built as part of the Palmerston defences of Portsmouth Harbour and now given over entirely to the history of how people have got underwater and come back. It is run by the Historical Diving Society, which owns and operates it, and staffed by volunteers, many of them former professional divers. It reopened in June 2026 after a major redevelopment that transformed the interior of the casemates.
The collection is the most comprehensive of its kind in Britain and among the best anywhere. Its spine is the copper helmet and standard dress tradition: the Siebe Gorman closed helmet of the 1830s that made sustained working dives possible for the first time, and the century and a half of development that followed, represented by helmets, corselets, weighted boots, canvas and rubber suits, hand and powered pumps, knives, tools and communication gear. Ranged around it are the alternative traditions — the early atmospheric diving suits that kept a diver at surface pressure, oxygen rebreathers, self-contained apparatus and the arrival of the aqualung after 1943.
The location is not incidental. Gosport is where the Royal Navy's diving branch was based, and where the physiology of decompression, the treatment of the bends and the limits of human tolerance to pressure were worked out — often on volunteers from the service, sometimes at real cost. The museum covers naval clearance diving, submarine escape training at HMS Dolphin, salvage work, and the commercial diving that supported North Sea oil.
Displays also follow the trade outwards from the Navy into salvage work, harbour and bridge construction, archaeology, and the commercial diving that supported North Sea oil from the 1960s onwards — a period in which saturation techniques pushed working depths far beyond anything the Victorian pioneers imagined, at a cost in lives that the museum does not skate over.
It is a compact museum in a dark, thick-walled Victorian fort, and the objects are unusually strange to modern eyes: brass, glass, canvas and lead assembled to keep a person alive somewhere no person should be. The volunteers who staff it are the other half of the attraction, since a good number of them wore this equipment professionally and will explain what it was actually like to work in.
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Plan Your Visit
⏱️ Recommended Visit Duration
💡 Visitor Tips
- The museum is seasonal and closes for the winter — do not plan a visit between late autumn and spring without checking first.
- In season it opens Fridays, Saturdays, Sundays and Bank Holidays only, 11:00am to 4:00pm.
- Talk to the volunteers: many are former professional or naval divers and the informal explanation is the best part of the visit.
- The casemates are cool and dim even in summer — bring a layer, which is not obvious advice for a seafront attraction.
- Entry involves a short flight of steps, but a platform lift was installed in the recent redevelopment; ask on arrival if you need it.
- Toilets are outside the museum building, in the public facilities by the car park.
- The car park adjoining the museum has eleven accessible spaces but fills on warm weekends when Stokes Bay is busy.
- Combine with the Royal Navy Submarine Museum two and a half kilometres away for a full day on the peninsula's underwater history.
Highlights
Siebe Gorman and the closed helmet
Augustus Siebe's closed diving helmet and watertight suit of the late 1830s is the object from which everything else in the museum descends. Earlier open helmets flooded if the diver bent forward; sealing the helmet to a waterproof dress made it possible to work at depth in any posture, and to stay down for hours rather than minutes.
Siebe Gorman, later based in London and Gosport, dominated the trade worldwide for over a century.
The museum's helmets trace the design's evolution in detail, and seeing the earliest alongside the latest makes the continuity of the tradition obvious.
The standard dress collection
Standard dress — copper helmet, brass corselet, heavy canvas or rubberised suit, weighted boots and lead breastplate, fed by air from a hand-cranked or powered pump on the surface — was the working uniform of the world's divers from the 1840s to the 1980s, and the museum holds an outstanding range of it.
The weight is the thing that surprises visitors: a full rig ran to well over eighty kilograms, comfortable underwater but nearly immobilising on deck. Suits, pumps, knives, tools, lifelines and telephone gear are shown together as a complete working system.
Atmospheric diving suits
A separate line of development sought to keep the diver at surface pressure inside an armoured shell, avoiding decompression entirely — an idea pursued from the nineteenth century through the Tritonia and JIM suits of the twentieth and into today's remotely supported systems. These machines look extraordinary, closer to a suit of armour or a small submarine than to diving dress, and the engineering problem they had to solve was the rotary joint: how to make a limb bend under pressure without leaking.
The museum explains the successive attempts, most of which failed instructively.
Decompression and the bends
The physiological displays cover the central problem of diving: that gas dissolved into the body under pressure forms damaging bubbles if pressure is released too quickly. Interpretation runs from the caisson workers of the nineteenth century, whose suffering gave the condition its name, through Haldane's staged decompression tables of 1908 to modern mixed-gas and saturation practice.
Much of this work was done at Gosport on naval volunteers, and the museum is candid about how the limits of human tolerance were established: by finding them experimentally, on people.
Collections
The Historical Diving Society's collection at Gosport is the most comprehensive record of diving technology in Britain. Its core is helmet and standard dress equipment from the 1830s onwards — copper helmets and brass corselets by Siebe Gorman and other makers, canvas and rubberised suits, weighted boots, lead breastplates, hand and powered air pumps, lifelines, telephone apparatus, knives and underwater tools.
Alongside this the collection covers atmospheric diving suits, oxygen and mixed-gas rebreathers, submarine escape apparatus, self-contained demand-valve equipment from the 1940s onwards, underwater cameras and lighting, and decompression and recompression material.
Documentary holdings include manufacturers' catalogues, manuals, photographs and the personal papers of professional and naval divers.
The history of diving
The main chronological display covering helmet and standard dress, atmospheric suits, rebreathers and self-contained apparatus from the 1830s to the present.
Diving physiology and safety
Displays on decompression, the bends, recompression treatment and the experimental work carried out at Gosport.
Themes
Time Periods
Current Exhibitions
No current exhibitions. Please check the museum website for updates.