WWII submarine comes back to life

When the Channel 4 "Salvage Squad" team were given just three months to restore a WWII one-man submarine, Wyko EMS released the pressure by renovating a 60-year-old motor in just 48h.

In preparation for the forthcoming third series on Channel 4, the "Salvage Squad" team were given just three months to restore one of the few remaining German Second World War "Biber" one-man submarines to full working order.

Everyone involved in both engineering and television production knows that project time and costs are difficult to control, but this is when Wyko EMS demonstrated how it could release the pressure by renovating a 60-year-old motor in just 48h.

How the "Biber" (or "Beaver") submarine came to be in the hands of the Royal Navy during the dying moments of WWII are as yet unclear.

However, after the war the midget submarine was put on display at HMS Ganges, and then in recent years, has formed part of the collection at the Royal Navy Submarine Museum, Gosport.

Earlier this year the museum consulted Ian Clark Restoration with a view to renovating the submarine, and an agreement was reached in July where Clark would oversee a restoration project that would involve the Salvage Squad team and the Navy's contracted ship repairer, Fleet Support.

FSL has an agreement with Wyko EMS for motor repairs and rewinds due to close proximity to its Gosport branch and Wyko's comprehensive repair capabilities, resulting in the submarine's 500V DC motor being handed over for evaluation.

During the submarine's life, it had spent many years unprotected outside, so when Wyko was asked to test and overhaul the unit within the 48h allocated for filming, the pressure was on.

The motor arrived at 0900 on Monday, when it was dismantled and the armature and field frame coils were steam cleaned for filming that morning.

Claire Barratt, Industrial Archaeologist and member of the Salvage Squad, arrived later that day to test the motor's conductivity under the guidance of Wyko's Terry Elsbury before an assessment could be made as to the extent of the job in hand.

Despite being 60 years old, the motor's results showed that it would be able take the power from the boat's batteries without the armature or field coils being rewound or any new components having to be made.

Wyko then set to work removing moisture residue through a stoving process and restoring its insulation value via varnish immersion.

Elsbury explains: "They came to the right place because, if there had been anything seriously wrong with the motor, we have the capability and expertise here to fix it quickly.

To reduce the submarine's size and weight, the motor was designed with an armature that had commutator bars flat to the end of its winding coils - not cylindrical as is usual - and with the brush gear running flat to the commutator face.

Even with this unusual design, we would have been able to fabricate replacement parts, machine surfaces, fit shafts, bearings manufacture a new commutator and rewind the armature or fields in our works if required".

While the motor armature and field coils were being treated, ready for assembly and testing the next day, the brushgear was dismantled, reinsulated and coated with antitracking paint and new carbon brushes were supplied and fitted.

Following the successful rotation tests on the Tuesday morning, the motor was transported back to FSL in order to keep the submarine's final assembly on target for the 29th October launch deadline.

With guidance from Heinz Hubler, a German war veteran and ex-Biber pilot, the submarine was successfully launched under the control of Tom Heron, a member of the Navy's LR5 submersible rescue team.

The Biber submarine is simple in comparison to a state-of-the-art LR5 and was easy to control during the successful launch.

However, the original pilots would enter enemy harbours controlling two 1.5t torpedoes, using a window that was prone to freezing up and a periscope that did not allow the user to see behind the boat.

Following the launch, the submarine will be displayed at the Royal Navy Submarine Museum at Gosport alongside the impressive HMS Alliance and the Royal Navy's first submarine, Holland 1.

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