On board the type 81 general purpose frigate HMS Zulu (1962) in Rosyth Dockyard during a lengthy refit which was completed in December 1974. A close detail of an unidentified item of machinery, possibly used for generating electricity. This is probably udergoing maintenance and the top cover has been removed. The machine is quite small and in a square framework in the centre is a coil of tightly wound wire. On either side of this framework are sprung units with insulated cables connected to a number of contact points by spade or ring fittings held in place by screws or nuts.