Difference between Distress Signal and Tidesman

DISTRESS SIGNAL vs TIDESMAN: NOUN

An international signal used by a distressed ship or aircraft to request help.
An internationally recognized signal sent out by a ship or plane indicating that help is needed

A customhouse officer who goes on board of a merchant ship to secure payment of the duties; a tidewaiter.
A tidewaiter.
One who is employed only during certain states of the tide.

Trawler, Cqd, Lifeboats, Cape verde islands, Alvei, Flotation device, Morse code, Vhf, Beep, Transponder, Alarm, Altimeter, Distress, Coastguard, Mayday

Boatage, Letter of marque, Staff officer, Underofficer, Ship money, Portgreve, Lastage, Bilander, Water bailiff, First officer, Keelage, First mate, Admiralty law, Landwaiter, Tidewaiter

Trawler, Cqd, Lifeboats, Cape verde islands, Alvei, Flotation device, Morse code, Vhf, Beep, Transponder, Alarm, Altimeter, Distress, Coastguard, Mayday

Boatage, Letter of marque, Staff officer, Underofficer, Ship money, Portgreve, Lastage, Bilander, Water bailiff, First officer, Keelage, First mate, Admiralty law, Landwaiter, Tidewaiter

Devastator warship, the ESS Crimson sends out a distress signal.
Three shotsfired at distinct intervals usually indicate a distress signal.
Dumbledore receives her distress signal and dives in after them.
Have you heard or seen distress signal from survival craft?
The flag is only put upsidedown as a distress signal.
Ceres Station when the crew receives a distress signal.
The trainee also surfaced and gave a distress signal.
The third image is not a distress signal.
Distress Signal The distress signal is MAYDAY, MAYDAY, MAYDAY followed by the name of station or station call letters repeated three times.
The Distress Signal Light emits a high _____________________________ visual distress signal visible for great distances.