AIS message type
AIS message type 13: Safety related acknowledgement
Confirms receipt of up to four type 12 messages. What type 13 carries, who sends it, how often, and how to read it.
What type 13 is
Type 13 acknowledges addressed safety messages, in the same way that type 7 acknowledges addressed binary messages.
How to read it
Protocol traffic. It carries no free text and no position.
Decoding it
The AIS message decoder reads the message type and sender MMSI of any sentence, including this one, but does not unpack the body of type 13.
All message types
| Type | Name |
|---|---|
| 1 | Position report, scheduled (Class A) |
| 2 | Position report, assigned schedule (Class A) |
| 3 | Position report, response to interrogation (Class A) |
| 4 | Base station report |
| 5 | Static and voyage related data (Class A) |
| 6 | Binary addressed message |
| 7 | Binary acknowledge |
| 8 | Binary broadcast message |
| 9 | Standard SAR aircraft position report |
| 10 | UTC and date inquiry |
| 11 | UTC and date response |
| 12 | Addressed safety related message |
| 13 | Safety related acknowledgement |
| 14 | Safety related broadcast message |
| 15 | Interrogation |
| 16 | Assignment mode command |
| 17 | DGNSS broadcast binary message |
| 18 | Standard Class B equipment position report |
| 19 | Extended Class B equipment position report |
| 20 | Data link management message |
| 21 | Aid-to-navigation report |
| 22 | Channel management |
| 23 | Group assignment command |
| 24 | Static data report (Class B) |
| 25 | Single slot binary message |
| 26 | Multiple slot binary message with communications state |
| 27 | Long-range AIS broadcast message |