Stabilisers for reducing the pitch and roll of ships; acoustic pulse-echo ranging apparatus for marine use; buoys for marine use; electric power supplies being rectifiers for marine use; electric power supplies being transformers for marine use; marine autopilots; marine communication apparatus; marine compasses; marine depth finders; marine depth sounders; marine logs (electric); marine navigation apparatus; marine transceiver grounding apparatus; marine transceiver grounding instruments; marine underwater acoustic devices; marine vessel steering apparatus (automatic); marine equipment in this class