Is it ex-mod or RNLI or something (the number on the leg looks like some sort of offical number). Some engines on rescue boats/lifeboats are fitted with fittings like that so they can be running (warming up) prior to lauching. Maybe this is one of those?
These are fitted by barrus to engines used for commerial use, normally where barrus fit the engine and as Tim M posted often found on RNLI, Coastgaurd etc. It is used for flushing the engine
White Noise
