Odd AIS safety message

[Ric]

A few days ago a large merchant ship passed about 3 miles CPA from me. My AIS pinged and I saw a message - can't remember now the exact wording, but something like " AIS safety message from <name of large merchant ship> - please ack". So I pressed OK to ack the message and that was the end of the matter.

What does this message mean?

 

[prv]

There's a lot more functionality in the AIS protocol than is commonly used. The less common parts of the protocol are not always fully or correctly implemented, especially by displays.

I imagine there was meant to be more message, which either wasn't transmitted, wasn't decoded by your display, or was subject to some UI bug that meant the obvious button didn't do the obvious thing of displaying it.

Pete

 

[Glenlivet]

I seem to remember seeing something similar, can’t recall whether on vhf AIS or transponder. I assumed it was just the ship confirming that I had seen it.

 

[MikeBz]

A few days ago a large merchant ship passed about 3 miles CPA from me. My AIS pinged and I saw a message - can't remember now the exact wording, but something like " AIS safety message from <name of large merchant ship> - please ack". So I pressed OK to ack the message and that was the end of the matter.

What does this message mean?

I've had this a few times as well, when not within reasonable proximity of anything else, and wondered what it was about. Like you I just press OK...

 

[sailor211]

I've had this a few times as well, when not within reasonable proximity of anything else, and wondered what it was about. Like you I just press OK...

So it is noted in his log that you would get out of his was&#55357;&#56397;

 

[Ric]

There's a lot more functionality in the AIS protocol than is commonly used. The less common parts of the protocol are not always fully or correctly implemented, especially by displays.

I imagine there was meant to be more message, which either wasn't transmitted, wasn't decoded by your display, or was subject to some UI bug that meant the obvious button didn't do the obvious thing of displaying it.

Pete

Thanks - that seems like a plausible explanation.

 

[Keith-i]

Some plotters have a message log. Might be worth looking to see if yours has as you’ll be able to review the message properly and possibly work out what it was all about.