1.4.9 Courses, distances, speed

Courses

Courses are to be expressed in 390 degrees notation from true north. State whether the course is TO or FROM a mark.

Distances

Distances are expressed in nautical miles or cables (tenths of a mile), and less frequently in kilometres or metres. The unit o measurement should always be stated.

Speed

Speed must be expressed in knots (i.e. nautical miles per hour). Speed is normally understood as speed through the water but ground speed (over the ground) may be indicated if necessary.

1.4.10 Ambiguous words (SMCP 2001 – p. 18)

Some words in English have meanings depending on the context in which they appear. Misunderstandings frequently occur, especially in VTS communications, and have produced accidents. Such words are:

The conditionals "may", "might", "should" and "could"

MAY

Do not say: "May I enter the fairway?"

Say: "QUESTION. Do I have permission to enter the fairway?"

Do not say: "You may enter the fairway."

Say: "ANSWER. You have permission to enter the fairway." Do not say: May I leave the berth?

Say: “QUESTION: Is it permitted to leave the berth?”

Do not say: You may enter the fairway.

Say: ANSWER: It is permitted to enter the fairway.

MIGHT: Do not say: I might drop the anchor.

Say: INTENTION: I will drop the anchor.

Do not say: "I might enter the fairway."

Say: "INTENTION. I will enter the fairway."

SHOULD: Do not say: You should anchor east of buoy D 5

Say: ADVICE. Anchor east of buoy D 5.

Do not say: "You should anchor in anchorage B 3."

Say: "ADVICE. Anchor in anchorage B 3."

COULD: Do not say: You could be running into danger

Say: WARNING: You are running into danger.

Do not say: "You could be running into danger."

Say: "WARNING. You are running into danger."

CAN:

The word "can" describes either the possibility or the capability of doing something. In the IMO SMCP the situations where phrases using the word "can" appear make it clear whether a possibility is referred to. In an ambiguous context, however, say, for example:

e.g. 1:

Say: "QUESTION. Do I have permission to use the shallow draft fairway at this time?"

Do not say: "Can I use the shallow draft fairway at this time?"

if you are asking for a permission. (The same applies to the word "may").

e.g. 2:

Do not say: Can I use the eastern port approach?

(if not disambiguated by the context of situation)

Say: Is it permitted to use the eastern port approach?

Note: In all cases the radiotelephone procedures as set out in the ITU Radio Regulations have to be observed.

1.4.11 Standard organizational phrases:

When it is advisable to remain on a VHF Channel / frequency, say:

"Stand by on VHF Channel ... / frequency ... ."

When it is accepted to remain on the VHF channel / frequency indicated, say:

"Standing by on VHF Channel ... / frequency ... ."

When it is advisable to change to another VHF Channel / frequency, say:

"Advise (you) change to VHF Channel ... / frequency ... ."

"Advise(you) try VHF Channel .. / frequency... ."

When the changing of a VHF Channel / frequency is accepted, say:

"Changing to VHF Channel ... / frequency ... ."

Corrections

When a mistake is made in a message, say:

"Mistake ..." followed by the word:

"Correction ... " plus the corrected part of the message.

e.g.:

"My present speed is 14 knots - mistake.

Correction, my present speed is 1-2, one-two, knots."

Readiness

"I am/I am not ready to receive your message."

Repetition

If any part of the message is considered sufficiently important to need safeguarding, say: "Repeat ... " - followed by the corresponding part of the message.

e.g.:

"My draft is 12.6 - repeat - one-two decimal 6 metres."

"Do not overtake - repeat - do not overtake."

When a message is not properly heard, say:

"Say again (please)."

Readability code:

In checking the readability of reception use the phrase:

"How do you read (me)?"

This may be answered as follows:

I read you ...

bad/one with signal strength one (i.e. barely perceptible)

poor/two with signal strength two (i.e. weak)

fair/three with signal strength three (i.e. fairly good)

good/four with signal strength four (i.e. good)

excellent/five with signal strength five (i.e. very good)