Not sure if this is an emergency compressor for a U boat, I have been assured it is . Quite where the person who told me it is got his information from I know not. I cannot find any information about it , did U boats have emergency compressors? It is German , wartime, and I have been told the colour is right for German navy . Can anyone tell me more , as can be seen the engine clips on to the compressor , for ease of movement I presume. Look forward to any info.