4 November 1944 Part 13

Continuation: repair of Battery Blücher gun, 4 November 1944

The principal problem was repairing the pneumatic recuperator, although a series of other tasks — including the elevation mechanism, cradle and construction of a completely destroyed mounting tail — also presented considerable difficulties.

By 28 September the gun had been repaired sufficiently to be proof-fired. At the first shot with a reduced charge, the recuperator, which had only been welded and ground smooth internally, tore apart at the front in pieces. Its piston rod bent so badly that it became unusable. A replacement recuperator was requested through air-supply channels from Germany. At the same time I ordered Oberleutnant Kern to seek a suitable method either of constructing a new one or repairing the old one.

The welding had been done badly; repair remained possible if a suitable piece could be found for the forward part of the recuperator. This was obtained by removing a compressed-air cylinder from the torpedo control position for the E-boats in Guernsey harbour. It could be spared without endangering use of the torpedo control position for S 112 should the boat again receive torpedoes.

The cylinder was cut up, one end screwed to the surviving portion of the recuperator, and the weakest point reinforced with a soldered strengthening ring. When two attempts at soldering still showed leaks, the ring was electrically welded. The front of the recuperator was sealed and reinforced with a screw cap. The newly constructed mounting tail was recalculated for its loads and strengthened accordingly. A new piston rod was manufactured. The recuperator was pressure-tested with water at 240 atmospheres gauge and fitted again.

The first day of proof firing revealed defects: the piston rod ground in its guide bush, and the gun ran in the cradle slides with considerable noise, probably because of stresses caused by the hit. By the second proof-firing day, 3 November 1944, the defects had been corrected sufficiently for the gun to be released for renewed service.

Some construction had to be simplified. The fine traversing mechanism, required only for a non-permanently mounted gun and unnecessary in its present role, was fixed in position; the mounting tail was made as simply as for a fixed gun. In this way a gun which in Germany would have required repair by the manufacturer rather than a naval dockyard was restored to operational condition.

Oberleutnant Kern, armourer Dischinger and the soldiers who carried out the repair deserved particular recognition. Oberleutnant Kern and armourer Dischinger — who had already distinguished himself in the repair of a 17 cm gun (see War Diary, 5 September 1944) — were awarded the War Merit Cross, 1st Class, and several soldiers the War Merit Cross, 2nd Class.

A destroyer remained on the southern waiting station throughout the day. Enemy convoy traffic observed during the day — to St Malo: one freighter with two masts and one funnel.

T-1022 Roll 2423, PG 37998, Commander of Sea Defences, Channel Islands. Source scan 0046 — original page 230