2. Communications at sea (Part I).

Maritime communications are used for safety, navigational, commercial and miscellaneous purposes. They take place within the ship herself, between the ship and other ships, between the ship and shore stations and sometimes between the ship and aircraft. Communications can be made over different distances and using methods ranging from the simplest to those using the most sophisticated radio technology.

The way to communication is possible by sound or visual signalling and by radio or electronic communications. Signalling is divided into flag signalling, flashing light signalling using Morse symbols, sound signalling by Morse symbol, or voice signalling over a loud hailer, and signalling by radio, i.e. radiotelegraphy.

Vessels on long voyages are often away from land for weeks or months at a time. Even on short voyages, a sailor on a boat is isolated from the land, and it is often difficult to know what is happening only a short distance away. It was natural, then, that early mariners would embrace technologies that allowed them to communicate across distances.

2. Written messages

One of the oldest methods of remote communication still exists today. One writes a message on a piece of paper and has it delivered to the recipient. For the sailor at sea, this meant receiving letters and important messages at ports where the vessel stopped or from friendly vessels encountered along the way. In some cases, it could take months or even years for a message to reach the addressee.

The ship's communicational equipment has undergone a revolutionary development and ranges from the traditional hand flags or arms, the hoist, flares, semaphore, bells, to the modern equipment used in radio or wireless telegraphy (WT), radiotelephony (RT) and satellite communications. SSB (single side band) transmitters, walkie-talkie sets, VHF and FM receivers,

telex, fax, satcoms, and computers displaying digital data are found on almost every modern ship.

4. Flags, semaphores, and other systems

Through the use of signal flags and semaphore, a message could be sent to anyone who could see it and understand it. Even today, when most communications are carried out by radiotelephony, signal flags are carried aboard most large vessels and many smaller ones. To avoid any possible misunderstanding the language of the safety communication procedures has been codified to identify the sender and recipient and to hide the meaning of the message, first into Morse Signaling Code, followed later by the International Code of Signals (ICS).

The flags used for signaling are known as pennants. There are a couple of different ways that the flags can be used to signal other vessels. In the first method, each pennant represents a letter of the alphabet, or a number, allowing complete words to be spelled. In the second method, the pennants are used to signal codes according to the International Code of Signals. This code was developed to allow boats to communicate with each other even if they don’t know each other’s language.

The International Code of Signals covers such items as maneuvering ships, towing, emergencies, medical problems and much more. This allows a wide range of communication between vessels that may have difficulty understanding each other's languages, are having radio problems, or may be having other problems.

IMO has standardized maritime English into what is known today as "IMO Standard Marine Navigational Vocabulary". "Seaspeak" is the most recent improvement of the IMO Standard Vocabulary for use in maritime communications, principally by VHF radio.

Any conversation, i.e. a ship-to-ship, ship-to-shore or shore-to-ship exchange consists of the following stages:

1. Making Contact

2. Exchange of Message

3. End Procedure

In the making contact stage it is usually necessary for one station to indicate the working channel and the other to agree to it.

In the message exchange procedure the following message markers (i.e. words introducing the content and purpose of the message) are:

Message Marker Answer to Message Marker

Question Answer

Instruction Instruction received

Advice Advice received

Request Request received

Information Information received

Warning Warning received

Intention Intention received

EXAMPLES

Question Answer

WHAT ARE YOUR INTENTIONS? I INTEND TO ALTER COURSE TO STARBOARD

Warning Warning received

BUOY NUMBER: ONE - FIVE UNLIT BUOY NUMBER: ONE - TWO UNLIT

In the end procedure the conversation is terminated (e.g. NOTHING MORE), using a

polite greeting (HAVE A GOOD WATCH, HAVE A PLEASANT VOYAGE TO) and the phrase OUT or OVER AND OUT.

SINGLE LETTER SIGNALS WITH COMPLEMENTS

May be made by any method of signaling.

A—with three numerals..............................................AZIMUTH or BEARING.

C—with three numerals..............................................COURSE.

D—with two, four, or six numerals............................DATE.

G—with four or five numerals.............. ……………LONGITUDE (the last two numerals

denote minutes and the rest degrees).

K—with one numeral...................................... ……….I wish to COMMUNICATE with you by...

L—with four numerals...................................................LATITUDE (the first two denote degrees

and the rest minutes).

R—with one or more numerals.......................................DISTANCE in nautical miles.

S—with one or more numerals........................................SPEED in knots.

T—with four numerals....................................................LOCAL TIME (the first two denote

hours and the rest min-utes).

V—with one or more numerals.......................................SPEED in kilometers per hour.

Z—with four numerals....................................................GMT (the first two denote hours and

the rest minutes)

Z—with one numeral.......................................................To call or address shore visual stations

(Numeral to be approved by local port authority).