fog signal
Harbor's misty alert
A fog signal is an audible warning used in low visibility to prevent collisions—typically a horn, bell, or siren on ships, lighthouses, or railways.
Before modern navigation, fog signals were essential for mariners: The foghorn sounded every thirty seconds.
Railroad fog signals were small explosive charges placed on tracks to warn approaching trains.
Loud maritime warning device
- diaphoneCompressed-air fog signal
- bellHollow resonating instrument
- gongStruck metal disc
- sirenWailing alert device
blast · resonance · echo · audible · soundwave · decibel · frequency · vibration
Compressed-air fog signal
- compressed airGas under high pressure
- clockworkSpring-driven gear system
- automaticOperating without intervention
- electricPowered by current
solar-powered · battery · sensor · remote · unmanned · maintenance · installation · range
Tethered nautical signal
- lighthouseCoastal beacon tower
- lightshipAnchored vessel with beacon
- beaconGuiding light source
- channel markerWaterway navigation aid
harbor · fairway · headland · shoal · reef · breakwater · pier · anchorage
Fine airborne moisture
- hazeMurky atmospheric suspension
- pea-souperExtremely dense fog
- murkThick atmospheric darkness
- shroudBurial cloth or covering
overcast · obscurity · gloom · whiteout · bank · low ceiling · poor visibility · socked in
foghorn
Loud maritime warning device
siren · blast · resonance · echo · audible · soundwave · decibel · frequency · vibration · loudness
diaphone
Compressed-air fog signal
- compressed airGas under high pressure
- clockworkSpring-driven gear system
- automaticOperating without intervention
electric · solar-powered · battery · sensor · remote · unmanned · maintenance · installation · range · candlepower
buoy
Tethered nautical signal
- lighthouseCoastal beacon tower
- lightshipAnchored vessel with beacon
- beaconGuiding light source
channel marker · harbor · fairway · headland · shoal · reef · breakwater · pier · anchorage · sea lane
mist
Fine airborne moisture
- hazeMurky atmospheric suspension
- pea-souperExtremely dense fog
- murkThick atmospheric darkness
shroud · overcast · obscurity · gloom · whiteout · bank · low ceiling · poor visibility · socked in
alert
Warning or watchfulness
collision · grounding · stranding · distress · emergency · precaution · vigilance · proximity · avoidance · notification
- lighthouse equipmentfresnel lens, lamp, beacon, foghorn, lantern
- lighthouse partstower, fresnel lens, gallery, light beam, rotating light
- military signalssalute, hand salute, signalman, signaler, parade rest
- navigation aidscompass, maps, road signs, signs, GPS
- signal lightsbeacon, beacon light, navigation light, warning light, emergency beacon
- ship alarmsmayday, SOS, man overboard, abandon ship, fire alarm
fog signallighthouse beam
Coastal tower's rotating light
light signal · visual signal · daymark · lighthouse · beacon
fog signallighthouse beam
Coastal tower's rotating light
lighthouse · beacon light · navigation light · harbor light · leading light
sign, fog, signal, foggy, signature, fogs, signals, signify, signaling