In early August Len Berey was invited on behalf of The Underwater Heritage Trust to give a lunchtime lecture to an invited audience at the Defence Science Technology Laboratories here in the U.K. The Trust owns a number of examples, both Italian and British, including an Mk.1 replica and the only known Mk.2 in existence. These examples are all housed at Eden Camp military museum, York. The addition of another Italian machine, an Mk.1 Maiale, is expected sometime later this year. As a result of this lecture and as a mark of appreciation for the commemorative work carried out by the Underwater Heritage Trust members of D.S.T.L. volunteered their services in order to conduct trials of the Trust's Mk.1 replica. This machine was commissioned to be built by young apprentice engineers involved with The Special Interest Group at Milton Keynes Training Workshop. A training facility supported by a number of engineering companies to foster the future of engineering within the community.

With the chariot now in serviceable order, and looking as though it had been nicked off the production line, the day came for the final water trials.

The trials took place within the controlled environment of The Defence Diving School's primary training facility at Horsea Island, Portsmouth, and formerly the Navies torpedo testing facility. With a lot of help from our Naval colleagues, who also very kindly provided the standby dive team, a chariot entered the water at its mother base for the first time since the Second World War

She was towed initially to the top end of the lake where a member of the trials team donned the only remaining diving apparel from around that period. This included a Sladen suit, a Siebe Gorman S.C.D.B.A. rebreather with an original Mk.2 hood and facemask assembly (see photo above). Gingerly mounting the forward operators position it first became apparent that she sat a little too high in the water and had a tendency to roll, the rear seat safety diver needed a considerable amount of white knuckle strength to keep an even keel by holding on to the access ladder. Venting both forward and aft trim tanks a little sorted this initial problem out but ballast was soon to prove a major problem overall. For the purpose of the trial the fundamental difference between the construction of the original and its replica were to prove slightly problematical. The method of trimming fore and aft tanks on the original was via an electrically driven pump. Using this method allowed the operator to pump water between tanks in order to trim effectively with little delay in the process. The replica relied solely on venting air from both trim tanks through small-bore pipe work in order to achieve the necessary trim and this in turn lead to a considerable delay in its action. The hull on the original Mk.1 Chariot had been constructed of rolled steel tube of about 0.25" thickness, a heavier gauge than that of the replica. In the original Chariot, within the main body cylinder between the forward and aft bulkheads, were housed a battery pack consisting of 30 lead acid cells used to power the electric pump and a 2hp electric motor to drive the main shaft to the propeller. The battery pack being laid along the floor along with the pump and control box, this acted as main ballast to increase displacement and keep the centre of gravity well below the waterline. In the replica the batteries have been substituted with rolled steel bars clamped to the floor to prevent any shift while in motion. The batteries in this case having been replaced by two heavy-duty units, each of 12 volts output, and moved to the aft motor compartment. Finally, with a dummy warhead and with the absence of a motorized pump to adjust trim between tanks, the replica was beginning to show some discrepancies in its displacement of 1.1 tons. The original had a displacement of 1.5 tons. What also came to light was that at Milton Keynes Training the initial trim and buoyancy tests on the replica were conducted within a fresh water facility. At Horsea the lake is fed with salt water increasing its density so the disparity in weight was further increased. As a result of this, Portsmouth's lead reserves were called into play to help seat her further into the brine. Finally at last, and with a gentle turn on the throttle bar, she slowly edged forward turning gently away from the dock in the most graceful of moves. This continued with rudder only manoeuvres describing arcs of around 30 meters to both Port and Starboard. She was then put into an initial dive to check the main ballast tank prior to any power input, but at this stage she remained at the surface while both forward and aft trim tanks were adjusted. With visors now just above the waterline the forward operator opened the throttle once more and applied forward pressure to the control yoke to bring the hydroplane into play. She left the surface silently for a brief nosedive before leaping out of the water, in a non-too literal sense, like a dolphin out of hot water followed by a wry comment from Len to confirm that nothing had changed since 1942. This time the problem was not too easy to solve and revolved around fluid movement within the dummy warhead. Government legislation for some reason prevents people from mounting live warheads on the front of their torpedoes. In order to overcome this weighty problem the dummy warhead for the replica was manufactured with two floodable compartments vented through a bleed valve mounted on the inside of the forward operators fairing. Because air was always present in these compartments after initial trimming, any forward inertia interrupted the trim as water moved to the rear of each compartment before surging to the front again. This time the problem had the better of us and could not be solved on site. Had the dummy warhead been filled with a solid medium it would have been impossible to handle with the facilities available but all these problems served as part of the learning curve.

After replacing the forward operator, who by now was breathing gas from his suit, the trial continued to a point where problems were either solved in situ, or else theories came to light that could be discussed and solved for a future trial. At the end of the day it turned out to be a very interesting experience for all those involved and the Navy saw a small part of its history briefly re-emerge. The Underwater Heritage Trust got to see their chariot back to where its early history and development started from and after all these years Len got to sit on the dock to watch others do the work for a change while allowing all his past memories to flood back once more.

This has been a very brief look at one small part of the roll played by some very brave men involved in the military diving profession of the last war. It was very much an unknown quantity at the time and forged more through desperation than any solid formula. Today brave men still choose to protect our rightful freedom in this way be it through combat, mine clearance or salvage of the aftermath where now a few brave women have chosen to tread. Even with a much greater understanding of the problems associated with this form of warfare and its associated apparatus, they may still have to stand alone in what will always be a very dangerous environment.

To Len Berey for sharing with me his experiences. Robert Hobson for furthering my knowledge on the history of the chariot and allowing me the use of the Underwater Heritage Trusts original b/w photo archive (all colour photos by the author). Tony Parfitt, the trials pilot, for all his patience up front during the trial and finally to all my colleagues who helped bring it all together. Thank you all.

Phil Nussle

All text and colour photographs are copyrighted © by Phil Nussle
All black and white photographs are official Royal Navy photographs
and made available through the Underwater Heritage Trust