IALA

Tidal window

Details:
Parameter No. of bits Description
Message ID 6 Identifier for Message 6; always 6.
Repeat Indicator 2 Used by the repeater to indicate how many times a message has been repeated.
0 – 3
0 = default
3 = do not repeat anymore
Source ID 30 MMSI number of source station
Sequence Number 2 0 – 3; refer to ITU-R M.1371-3, Annex 2, § 5.3.1
Destination ID 30 MMSI number of destination station.
Retransmit Flag 1 Retransmit Flag should be set upon retransmission.
0 = no retransmission = default
1 = retransmitted
Spare 1 Not used. Set to zero.
IAI 16 DAC = 001; FI =32
Time Stamp  UTC Day UTC date of the data.
UTC Month 4 1 – 12
0 = not available = default
UTC Day 5 1 – 31
0 = not available = default
Position #1 Longitude 25 Longitude in 1/1,000 min, ±180 degrees as per 2’s complement (East = positive, West = negative).
181 = not available = default
Position #1 Latitude 24 Latitude in 1/1,000 min, ±90 degrees, as per 2’s complement (North = positive, South = negative).
91 degrees = not available = default
From UTC Hour 5 0 – 23
24 = not available = default
From UTC Minute 6 0 – 59
60 = not available = default
To UTC Hour 5 0 – 23
24 = not available = default
To UTC Minute 6 0 – 59
60 = not available = default
Current Direction predicted #1 9 Direction of Current 1, in 1 degree steps.
0 – 359 degrees
360 = not available = default
361-511 (do not use)
Current Speed predicted #1 8 Speed of Current 1, in 0.1 knot steps.
0.0 – 25.0 knots
251 = speed 25.1 knots or greater
252 – 254 (reserved for future use)
255 = not available = default
Position #2 Longitude 25 Longitude in 1/1,000 min, ±180 degrees as per 2’s complement (East = positive, West = negative).
181 = not available = default
Position #2 Latitude 24 Latitude in 1/1,000 min, ±90 degrees as per 2’s complement (North = positive, South = negative).
91 degrees = not available = default
From UTC Hour 5 0 – 23 24 = not available = default
From UTC Minute 6 0 – 59 60 = not available = default
Notice from webmaster:
In this prediction the To UTC Hour and to UTC Minute is missing.
Current Direction predicted #2 9 Direction of Current 2, in 1 degree steps.
0 – 359 degrees
360 = not available = default
361-511 (do not use)
Current Speed predicted #2 8 Speed of Current 2, in 0.1 knot steps. 0.0 – 25.0 knots
251 = speed 25.1 knots or greater.
252 – 254 (reserved for future use)
255 = not available = default
Position #2 Longitude

Notice from the webmaster:
#2 should be #3

25 Longitude in 1/1,000 min, ±180 degrees as per 2’s complement (East = positive, West = negative).
181 = not available = default
Position #3 Latitude 24 Latitude in 1/1,000 min, ±90 degrees as per 2’s complement
(North = positive, South = negative).
91 degrees = not available = default
From UTC Hour 5 0 – 23
24 = not available = default
From UTC Minute 6 0 – 59
60 = not available = default
To UTC Hour 5 0 – 23
24 = not available = default
To UTC Minute 6 0 – 59
60 = not available = default
Current Direction predicted #3 9 Direction of Current 3, in 1 degree steps.
0 – 359 degrees
360 = not available = default
361 – 511 (not used)
Current Speed predicted #3 8 Speed of Current 3, in 0.1 knot steps.
0.0 – 25.0 knots
251 = speed 25.1 knots or greater
252 – 254 (reserved for future use)
255 = not available = default
Total  350 occupies 3 slots