Exchange

Exchange procedures are most common in spoken maritime interactive communications. In many ways they resemble normal phone conversations between two speakers. However, in maritime VHF exchanges each speaker must wait for his turn. The two parties to communication are called: CALLING STATION (sender) and RESPONDING STATION (receiver). Both stations must strictly adhere to the rules of ITU radio regulations and IMO SMCP 2001.

The principal elements or units of a maritime conversation are:

· exchange

· turn

· move

· act

Exchange

The exchange is the smallest interactive unit in maritime conversation. In a maritime conversation by VHF or any other voice radio-communication two stations briefly discuss a topic, ask for information and respond to it, agree to a suggestion, etc. They can converse over a simple topic (e.g. how to avoid collision) or over a number of topics within a single conversation. Basically, an exchange is a conversation between two stations on a single topic (e.g. current position of the ship). It refers to a single topic and consists of two turns, one held by the controlling station (first speaker/ship/shore-based station) and the other by the responding station (second speaker/ship/shore-based station).

Two turns referring to a single topic (the subject of conversation) make a maritime exchange. A single exchange, or more usually, two or more exchanges on a single or a number of topics, make a maritime VHF conversation.

Turn

A turn is the time one station uses (or is allowed) to speak in order to say:

- what it intends to do or what it expects the other station to do,

- ask for information

- request or seek advice, etc.

A turn represents everything one speaker says or asks ‘at one go’, i.e. the time between his pressing and releasing the speaker key on the VHF radiotelephone. The turn-giving signal (over) is used to signal to the other station to take the turn. Any exchange must necessarily contain two turns: calling and responding. The speaker normally ends his turn by using the word ‘ over ’ as a signal indicating that he has finished his turn and that the turn is yielded or given to the hearer, who then takes the turn in the process called turn-taking.

Moves and acts

The most important part of a turn in the exchange is the move or act. It is the speaker’s contribution to the exchange and success of conversation. This may consist of a word, phrase or a sentence which the speaker uses in his turn to express his intention or purpose of communication (MAYDAY RECEIVED; WHAT ARE YOUR INTENTIONS?; WHAT ARE MY BERTHING INSTRUCTIONS?, etc.).

e.g. 1: Station One: ‘What are your intentions? ’;

Station Two: ‘Intention: I shall alter course to starboard, new course 234 degrees.”.

An act is any word, phrase, sentence or other expression of speech acts used as a marked means of asking for information, making a request, giving intention, expressing advice etc. represents the speaker’s move, i.e. what s/he intends to say or ask.

The primary acts in any conversation are: ACCEPT, ACKNOWLEDGE, AGREE, ANSWER, APOLOGY, CALL-OFF, CHECK, CONFIRM, DISAGREE, GREETING, EVALUATE, INFORM, INVITE, OBJECT, OFFER, OPPOSE, QUESTION, REACT, REJECT, REPLY, REQUEST, THANK.

The principal acts in maritime VHF or other spoken communications are: QUESTION, ANSWER, INFORMATION, INSTRUCTION, ADVICE, REQUEST, INTENTION, WARNING. These are referred to in SMCP 2001 as MESSAGE MARKERS and introduce the speaker’s intention or what he is going to say, ask, request, require, advise, command or prohibit.

2. (PART 2) CONDUCT OF MARITIME RADIOTELEPHONE CONVERSATIONS