AIS Message Definitions

AIS Message: imo_tidal_window (001:13:)

Description:

IMO tidal window. Specified in SN/Circ.236 Annex 2, page 5, Application 3. Also defined in IALA Guidelines on AIS, Vol 1, Part 1, Ed. 1.3. Guildeline No 1028. This message should be used to inform vessels about tidal windows which allow a vessel the safe passage of a fairway. The message includes predictions of current speed and current direction. In this example, three points of tidal information are given. Attributes of message: addressed, shore station transmitting, acknowledgement required.

Name NumberOfBits ArrayLength Type Units Description
MessageID 6 uint AIS message number. Must be 6
RepeatIndicator 2 uint Indicated how many times a message has been repeated
0: default
3: do not repeat any more
UserID 30 uint MMSI number of transmitter broadcasting the message
SeqNum 2 uint Sequence number as described in 5.3.1. Assigned to each station
DestinationID 30 uint Unique ship identification number (MMSI)
RetransmitFlag 1 bool Should be set upon retransmission
0: no retransmission
1: restransmitted
Spare 1 uint Must be 0
dac 10 uint Designated Area Code - part 1 of the IAI
fid 6 uint Functional Identifier - part 2 of the IAI
month 4 uint UTC month
day 5 uint UTC day
window1_longitude 28 decimal degrees Not sure what this position is for? Center? East West location
window1_latitude 27 decimal degrees Not sure what this position is for? Center? North South location
fromhour1 5 uint hours From UTC hour
frommin1 6 uint minutes From UTC minute
tohour1 5 uint hours To UTC hour
tomin1 6 uint minutes To UTC minute
curdir1 9 uint degrees Current direction
curspeed1 7 udecimal knots Current speed
window2_longitude 28 decimal degrees Not sure what this position is for? Center? East West location
window2_latitude 27 decimal degrees Not sure what this position is for? Center? North South location
fromhour2 5 uint hours From UTC hour
frommin2 6 uint minutes From UTC minute
tohour2 5 uint hours To UTC hour
tomin2 6 uint minutes To UTC minute
curdir2 9 uint degrees Current direction
curspeed2 7 udecimal knots Current speed
window3_longitude 28 decimal degrees Not sure what this position is for? Center? East West location
window3_latitude 27 decimal degrees Not sure what this position is for? Center? North South location
fromhour3 5 uint hours From UTC hour
frommin3 6 uint minutes From UTC minute
tohour3 5 uint hours To UTC hour
tomin3 6 uint minutes To UTC minute
curdir3 9 uint degrees Current direction
curspeed3 7 udecimal knots Current speed