THE REBREATHERS USED BY DIVERS FROM AUSTRALIA’S WWII MIDGET SUBMARINES

Australia had a fleet of XE-craft midget submarines (35 ton) during World War II. Six of these XE-craft submarines were despatched to the Far East on 21st February 1945.

XE-3

(Source: https://www.ozatwar.com/navy/xe-craft.htm )

One of the fleet’s missions was to cut the undersea telephone cable between Singapore and Tokyo, which runs via Indochina and Hong Kong. Underwater cables were being used by the Japanese for sending and receiving High Command messages. The six secret XE-craft trained on a quiet part of the Queensland coast north of Brisbane. The location was chosen to avoid the possibility of being spotted by any Japanese reconnaissance aircraft. The fleet practised on a disused submarine telegraph cable that ran between Mon Repos and New Caledonia. It was originally laid in 1893 and abandoned between 2 & 5 years later.

The XE-craft would submerge to a depth of 5-6m. One of the divers would then go into the wet-and-dry compartment, a hatchway in the submarine into which a man can crawl from inside the submarine. This compartment is initially dry. By opening various valves, the compartment fills with water and then the diver can open a lid to exit the submarine into the open sea.

The diver would then retrieve a grapnel from a storage container on the outside of the XE-craft. This grapnel remained attached to the submarine by a 15m length of stout manila rope. The grapnel was then dropped to the ocean floor in the direction of the undersea cable. The diver then re-entered the submarine by the wet-and-dry compartment. The XE-craft then submerged to a position 3m above the sea bed. The Commander of the XE-craft maintained this depth by the sounding equipment in front of him. As the submarine moved forward, the grapnel would catch on to the undersea cable and, as the slack in the manila rope took up, the XE-craft would come to a stop.

The commander of the XE-craft would then settle his submarine on the bottom and the diver would again exit the vessel via the wet-and-dry compartment. This time he would take with him some special hydraulic cutters to cut the cable that they had located with the grapnel. The diver would then re-enter the XE-craft via the wet-and-dry compartment.

The submarine divers were able to test their "free" diving equipment during this cable cutting exercise. The divers wore a “Proto”, a sort of oxygen apparatus plus a regenerative fitment. The apparatus was a closed circuit system which was used to avoid any air bubbles coming to the surface during dangerous missions in enemy held areas.

The “Proto” is a type of rebreather that was made by Siebe Gorman – see https://en.wikipedia.org/wiki/Siebe_Gorman_Proto . Its breathing bag was worn on the chest. It was an industrial breathing set and not suitable for diving. It was made from 1914, or earlier, to the 1960s or later.

Siebe Gorman “Proto”, seen from the front

at the National Coal Mining Museum for England

(Source: https://en.wikipedia.org/wiki/Siebe_Gorman_Proto)

It had one or two oxygen cylinders, across the lumbar part of the back. Its duration in use was one or two hours, dependant on the size of the oxygen cylinder fitted. Its absorbent (trade name “Protosorb”) was loose in the bottom of the breathing bag, restrained by a perforated cloth partition, and not in a canister. It had two wide breathing tubes running from the breathing bag to either a strapped-in mouthpiece (used with goggles), or an industrial-type full-face mask known as a “Vistarama” face mask, with a curved window and an inner oronasal mask.

The carbon monoxide that the divers breathed out passed through the Protosorb absorbent. This chemical was soda lime granules comprising of mostly calcium hydroxide (Ca(OH)2) – slaked lime. This would partially regenerate the carbon monoxide back to pure oxygen. If divers worked below the safe depth of 9m and were involved in very energetic activities, the risk of oxygen poisoning increased.

The canister on the front of the bag was to cool the gas in circuit. The absorbent would get warm as it absorbed carbon dioxide. That warming of the gas in circuit was welcome when scuba diving in cold water, but it was not welcome in hot industrial situations, including deep mines.

It was used by firefighters and also by rescuers in coalmines, long before open-circuit industrial breathing sets based on the aqualung became common.

The first version was designed by Fleuss and Davis in about 1906-1910. It had equal balance back and front of the wearer, and avoided projections on the back that could catch when crawling through holes. The more vulnerable parts were in front, in sight of the wearer. The reducing valve was of the constant feed type. [1]

Oxygen poisoning affects an individual's mind such that they believe that they are not in danger and able to cope with anything. Two divers wearing this "free" diving equipment were lost on two consecutive days.

It would appear, upon investigation, that both divers had gone too deep. Although 9m (30 feet) was the safe working depth for the "free" diving equipment, one of the divers had gone down to 14m and had worked very hard against the tide during his dive.

The two lost divers were David Carey and Bruce Enzer. There is a memorial panel for them both at the Portsmouth Naval Memorial, Hampshire. Carey’s panel is number 88, Column 3. Bruce Enzer’s panel is number 90, Column 2. [2]

There is also a memorial to them at Burnett Heads, Hervey Bay, Queensland. The Burnett Heads Submariners Memorial is located at Memorial Park, at the corner of Zunker and Moss Streets, Burnett Heads. It was unveiled in 1995 and some of the Australians who served in X-craft were in attendance. [3]