Under the aegis of WMO, IMD has enlisted a cooperating fleet of Voluntary Observing Ships for collection of meteorological observations from ocean areas.  The VOF consists of merchant ships of Indian registry, some foreign merchant vessels and a few ships of the Indian Navy, totalling 203.  These ships have Meteorological instruments supplied by IMD.  The observations are transmitted by the ships to the nearest coastal radio stations for onward transmission to the storm warning centres. Records of observations are passed on to the Department when the ships call at ports. IMD's Port Meteorological Offices provide asistance for callibration and maintenance of the equipment on board the ship.