Water Level Message

Permitted as from:

09/03/2002

Registrant:

Saint Lawrence Seaway Development Corporation

Physical link:

AIS

Message number (0=VDES-VDE):

DAC or VPFI:

366

FI / Message ID:

Sub:

Technical point of contact:

U.S. Department of Transportation
John A. Volpe
Transportation Systems Center
55 Broadway
Cambridge, MA 02142

State:

in force

Number of slots (max):

Last modified:

10/04/2022 - 12:36

Reporting Rate:

Each individual Seaway message has an assigned update interval established by the Seaway Traffic Management System (TMS). However, the AIS network may elect to retransmit any messages, system resources permitting, at more frequent intervals.

Used by:

Saint Lawrence Seaway Development Corporation

Details:

Parameter	Number of bits	Description
Designated Area Code	10	The Designated Area Code will be 366 for the United States or 316 for Canada depending on the location of transmitter. Refer to Section 1.1 for description
Function Identifier	6	FI=1
Reserved	2
Message ID	6	Message Identifier = 3 (00 0011 in binary)
Binary Data	Max 864	From 1 up to 4 wind information reports, each structured as defined in next table.
Total Number of bits	Max 888	= 24 + N*144
		N Total Bits	(Slots Required)
		1 168 bits	(2 slots)
		2 312 bits	(2 slots)
		3 456 bits	(3 slots)
		4 600 bits	(4 slots)
		5 744 bits	(4 slots)
		6 888 bits	(5 slots)

Parameter	Number of bits	Description
Timetag	20	Month, Day and Time of measurement, See UTC Time
Station ID	42	Seven 6-bit ASCII character ID
Longitude	25	Longitude in 1/1000 minute (±180 degrees, East = positive, West = negative. 181 degrees = not available)
Latitude	24	Latitude in 1/1000 minute (±90 degrees, North = positive, South = negative. 91 degrees = not available)
Water Level Type	1	0 or 1; 0 = Relative to reference datum , 1 = Water Depth , Note: Always 0 for Saint Lawrence Seaway
Water Level	16	Water level in centimeters -327.67 to +327.67 meters, -32767 = -327.67 m or less, +32767 = +327.67 m or greater -32768 = not available
Reference Datum	2	Defines datum used 0 = MLLW 1 = IGLD-85 2,3 = reserved for future use Note: Always 1 for Saint Lawrence Seaway
Reserved	14	Reserved for future use
Total Number of bits	144

UTC Time

Parameter	Number of bits	Description
Month	4	Month of year (01- 12 Month); 0 = not available; 13-15 not used
Day	5	Day of month (01 - 31 Days); 0 = not available
Hours	5	UTC Hours (0-23); 24 = not available; 25-31 not used
Minutes	6	UTC Minutes (0-59); 60 = not available; 61-63 not used
Total number of bits	20

Water Level Report