Testing the Type XXI

[pythos1]

Earlier I posted about the actual problems encountered with the type XXI's charging system. The charging voltage was just under the needed voltage to fully charge the battery therefore the batteries never got fully charge. This was due to the XXI in effect being a diesel electric sub. While cruising on the surface the weak diesles were supplemented by the electric motors. Not to mention the tremendous electrical load of the sub's systems added to the strain to the charging system. All auxillary pumps, hydraulics and so were electrically powered, very few engine driven auxillaries.

Concerning the snorkel. All german subs had the snorkel fresh air exhaust into the pressure hull, to both provide ventilation, as well as air for the diesles. Only American subs with snorkels had units that directly connected to the diesles, this was because of the unacceptable need to keep the engine room doors open while snorkelling, and the heinous negative pressure experiences when the snorkel valve got closed by wave action. But this required extra blowers connected the air supply of the snorkel which caused more noise, whereas the german method actually cause a circulation within the hull. Fresh air induction into the pressure hull would indeed take less than an hour as it does with the SHIII type XXI, along with the older boats snorkel equipped.