NAVIGATION AID

SN Buildings, sites and structures used by mariners for purposes of navigation.
CL MARITIME
NT BUOY
COAST LIGHT
COASTGUARD STATION
COASTGUARD TOWER
FOG HORN
LANDMARK TOWER
LIFEBOAT STATION
LIGHTHOUSE
LOOKOUT
RADIO POSITIONING STATION
REFUGE BEACON
SEA BEACON
SEA MARK
SIGNALLING BATTERY
TIMEBALL TOWER