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The Ex Files

by Gerald W. Sigrist

From top: HMS/M Explorer enters Copenhagen, Denmark, in 1960; HMS/M Excalibur performs a high-speed run in 1959; HMS/M Excalibur arrives at Cambelltown Harbour, Scotland; Submariners at work in the motor room of one of two experimental submarines fuelled by high-test peroxide.

From 1954 to 1966, the Royal Navy provided submarines that deployed from Halifax to train Canada’s anti-submarine navy. The Royal Canadian Navy reciprocated by sending personnel to the United Kingdom to replace the RN crew members assigned to these subs, and to train Canadian submariners prior to the RCN obtaining the Oberon-class subs. I was part of this program, and starting in 1958 served approximately 7 1/2 years in the United Kingdom as well as some time on a British submarine based in Halifax.

One of the most remarkable periods was from 1959-61. That was when I served on two experimental subs the RN had in commission.

To understand how these subs came to be, it is necessary to take a short history lesson.

In 1945, the British and Americans held a number of captured U-boats, among these were two prototypes of the Walther design that were built around an experimental engine fuelled by high-test peroxide. One boat, U-1406, was handed over to the Americans. The other, U-1407, was rebuilt by the British. In fact, the British spent a considerable amount of time trying to make the U-boat’s explosive, peroxide-based fuel into a safe operational proposition.

Built by Blohm & Voss at Hamburg, Germany, U-1407 was laid down on Nov. 13, 1943, and commissioned on March 13, 1945. She was scuttled at Cuxhaven on May 5, 1945, but within a month was found and raised. She was then rebuilt and commissioned as HMS/M Meteorite.

The British subsequently built two improved versions of Meteorite while the Americans abandoned the concept in favour of pursuing a nuclear-powered sub program which resulted in them launching the world’s first nuclear-powered sub, USS Nautilus, in January 1954.

The basis of the Walther system was the chemical hydrogen peroxide, a relatively unstable compound that breaks down into water and oxygen. The name HTP was given to the very high concentration of the solution required to operate the Walther turbine. It was a colourless liquid considerably more viscous than water and liable to explode if its temperature rose too high. As the composition produced a great deal of heat, operating an HTP submarine was like driving a tank loaded with nitroglycerine across a battlefield.

To make matters worse, a fire could not be extinguished by smothering it with foam as the compound contained sufficient oxygen to maintain combustion. The only way to fight a fire was to dilute the HTP with lots of water.

But despite all the problems and dangers, the RN pressed on with the building of two streamlined versions designed for high underwater speed. The method of propulsion put them among the fastest submarines in the world, and for a time the blue pennant was flown to denote this.

The submarines were also fitted with one diesel engine and a modern version of main motors and battery to provide diesel electric power. These subs provided valuable training experiences for airborne and surface anti-submarine forces, but the advent of nuclear-powered submarines rendered these boats obsolete.

The experimental or Ex-class submarines were built by Vickers Armstrong, Barrow and named HMS/M Explorer and HMS/M Excalibur and later, because of certain incidents, were dubbed Exploder and Excruciator. Explorer was launched March 5, 1954, and completed in 1956. Excalibur was launched Feb. 25, 1955, and completed in 1958.

The displacement of each sub was 780 tons surfaced and 1,000 tons submerged. They were just over 225 feet in length. Both had a complement of roughly 45 men.

A fuelling depot, complete with docking facilities, was built for the subs at Faslane on the Gareloch in Scotland next to the RN’s 3rd Submarine Squadron base and depot ship HMS Adamant. A retired water tanker, the RFA Spabeck, was brought back into service and adapted to carry the HTP fuel to the submarine when it was operating away from Faslane. She carried a small civilian crew specially trained for their role to handle the only job of its kind in the navy.

The submarine carried the fuel in huge polyethylene bags that were fitted between the sub’s pressure hull and outer casing. This arrangement constituted safety arrangements so the fuel could be diluted with water and rendered harmless in the event of an accident.

The submarine was fitted with a diesel engine in the fore ends and no one could enter the turbine space when in use. Overall, there was very little space for accommodations. At sea in these boats, the term “hot bunking” was very real. It was used to describe how one bunk would be shared between a submariner going off duty and one coming on duty.

In harbour, the problem of living space was eased by the use of a tender to serve as accommodation ship. Two ships HMS Minor I and Minor VIII, both former minelayers, were commissioned and one travelled with each sub.

No extra crew was available and so the submarine had to provide the small crew needed to take the ship out to sea for short trips. For longer trips, personnel were borrowed from wherever possible. And so the RN had three support vessels at work in its attempt to make a system work that was doomed to failure.

Most of our work was carried out in deep waters off Campbeltown, Scotland, usually returning at night to refuel and carry out the never-ending repairs and adjustments to the turbines. A great deal of credit must be given to the engine room staff who put in many long hours to keep the extremely temperamental turbines operating. Most days the submarine would do exercise with ships and aircraft returning to the jetty in Campbeltown, only to have the engine room artificers working most of the night to right problems so we could run again the next day.

After completing my submarine training in HMS Dolphin, the RN’s submarine school in Gosport, England, I joined Excalibur in January 1959. My trade was radioman and I would be the senior radio operator in charge of the communications department. I remained with Excalibur until she decommissioned for major refit in December 1959. It was a fairly uneventful year with little excitement and lots of long hours and hard work.

The crew was dispersed far and wide, but the navy chose to send me to Explorer. This suited me just fine because the job was second nature to me and my family was situated in nearby Helensburgh, Scotland. The only thing that changed for me was the name of the submarine.

During 1960 we made an R & R trip to Copenhagen, Denmark. While leaving Copenhagen we sighted and later picked up a dead body. The authorities were notified and eventually came to collect it. Someone made a comment about it being a bad omen, and this soon proved to be true. Shortly after the discovery, our one diesel engine blew a piston and it completely broke down. The nearest port was in Sweden, and it was within reach using the power in our battery. So, we went in using main motors.

It was my job to get a message to shore authorities and request a berth. I was finally able to contact them as we were entering harbour, and they were certainly surprised with our unannounced visit.

We ended up at a jetty, far removed from civilization, near Russian ships that were unloading coal. It was dirty and dusty and we laid there for 10 days awaiting spare parts and or a tug to escort or tow us back to Scotland.

Most of the crews’ spare money had been spent in Copenhagen, so there was very little to go around for anyone to go ashore. I was also the boat’s postman, and the Swedish army sent a car daily for me to visit the downtown post office. And so I was one of the few who saw any of the scenery. Needless to say, the tug was very welcomed on arrival and we were glad to get back to Scotland.

In 1961, Explorer had an occasion to be exercising with a ship off Campbeltown, running on the surface. Running on the turbine was called “fizzing”. The process emitted a great deal of carbon monoxide, normally dispensed harmlessly in the sea when submerged. As it was flat calm a decision was made to charge the battery by running the diesel as well as the turbines. This caused a serious problem.

The carbon monoxide was now going in the air and, with only the conning tower hatch open, the diesel began to suck this air into the boat. By the time the CO2 content gauge was read by a petty officer in the control room, our air was at a very dangerous level.

The boat was stopped, all hatches opened, and the crew began to escape to the casing. On reaching fresh air, several men passed out, as their lungs were saturated with CO2.

After informing the accompanying ship, I made my way up the conning tower only to have a sailor fall back on me as he tried to get out. With someone pulling from above and me pushing from below, we managed to clear the sailor from the tower.

I seemed fine until the fresh air mixed with my CO2-filled lungs and then I became very dizzy. However, I recovered quickly.

We arrived back in port with a few of the crew still lying on the casing. These men, who had been covered with blankets, were removed to hospital. Luckily, all of them survived. There was a board of inquiry and we were told that another few minutes in the boat would have been fatal. I suppose it was our lucky day.

During my time in these submarines there were other small incidents that were usually laughed off as being routine. It takes a lot to bother a submariner.

A dozen or so Canadians served in one or the other of these two experimental subs, but I believe I am the only Canadian submariner who spent time in both. Excalibur was put on disposal list in January 1965. She was sold to T.W. Ward Ltd. and towed from Barrow to be broken up on Feb. 5, 1970. Explorer was also sold to T.W. Ward and handed over for breaking up on Feb. 8, 1965.


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