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Flags are still very much used around the world. Visual signalling leaves no trace and can only be seen by those who you can see. Radio transmissions can be de

by mjlee 10y ago

Flags are still very much used around the world. Visual signalling leaves no trace and can only be seen by those who you can see. Radio transmissions can be detected by sensors you don't know are present. This is useful for navies. They're reasonably quick, reliable and transcend language barriers. They also work well as a broadcast method - you can hoist Flag Alpha and every ship in visual range will know you that have a diver in the water and to use caution in your vicinity, you don't need to create excess chatter by announcing it on radio every 5 minutes. Also, when you need a laugh during a long and boring watch you can get someone junior on the bridge to read out the ICS definition for Single Letter Signal Flag Zulu.

j4_james 10y ago
Yeah. As someone who lives on navigable river, it's not uncommon for me to see boats flying signal flags for variety of reasons. There's not a wide range of usage here mind you - it's typically tugs and workboats flying the RY signal (you should proceed at slow speed when passing me), survey vessels flying IR (I am engaged in submarine survey work) or cruise ships flying the H signal (I have a pilot on board). Naval vessels are kind of an interesting case though. They also fly the H flag when they have a pilot on board, but when they do so it's in combination with the answering pennant at the top of the hoist. I believe this is a standard practice when communicating with merchant marine vessels to indicate that the signal is based on the ICS rules and not the naval signal book which can mean something completely different. Naval vessels also often display their call sign using these signal flags when arriving and departing from port.
- mjlee 10y ago
  Code Hotel distinguishes "I have a pilot on board" from Hotel meaning "I am conducting rotary-wing flying operations".
legodt 10y ago
For those unwilling to google: I require a tug

by mjlee 10y ago

j4_james 10y ago

Yeah. As someone who lives on navigable river, it's not uncommon for me to see boats flying signal flags for variety of reasons. There's not a wide range of usage here mind you - it's typically tugs and workboats flying the RY signal (you should proceed at slow speed when passing me), survey vessels flying IR (I am engaged in submarine survey work) or cruise ships flying the H signal (I have a pilot on board). Naval vessels are kind of an interesting case though. They also fly the H flag when they have a pilot on board, but when they do so it's in combination with the answering pennant at the top of the hoist. I believe this is a standard practice when communicating with merchant marine vessels to indicate that the signal is based on the ICS rules and not the naval signal book which can mean something completely different. Naval vessels also often display their call sign using these signal flags when arriving and departing from port.

mjlee 10y ago
Code Hotel distinguishes "I have a pilot on board" from Hotel meaning "I am conducting rotary-wing flying operations".

legodt 10y ago

For those unwilling to google: I require a tug