9 MARINE APPARATUS AND INSTRUMENTS FOR COMMUNICATIONS AND SIGNALLING, NAVIGATION, MARINE LIFE DETECTION, AND ENVIRONMENTAL CONDITIONS MEASUREMENTS, NAMELY, KNOTMETERS, WIND SPEED METERS, WIND DIRECTION INCICATORS, DIRECTION FINDERS, ELECTRO-OPTICAL FISH INDICATING UNITS, TELEPHONE AND RADIO UNITS, HAILERS, MAGAPHONES, AND PARTS THEREOF; BATTERY CHARGERS