AIS toggle between sail/power?

[johnalison]

It will be another generation before leisure sailors broadcast all this information, so I don't see the point in worrying about it. I don't think that my little craft represents a great threat to the average ship, but on the whole believe that their masters have my interests at heart, and if I make my position, speed and direction clear they will generally do the right thing.

Information received on AIS is frequently inaccurate, and although the vector information is usually correct, I often see ships "at anchor" while moving at twenty knots, or yachts 600' long or more. There is also a suspiciously large number of 33ft yachts, presumably a default setting in some systems.

 

[prv]

I think because Type tells you what you are contending with. What you might be looking for. You are a container ship. An AIS target appears 10NM away. You engage Mark 1 eyeball where the AIS says it should be and fail to see it... Why? If you look at the vessel type and it says Pleasure Craft you know it might be a 6m Rib with black toobs. If you look and it says its a 300m Tanker carrying hazardous cargo you search harder!

More like what Bru says - although it seems to have become the main use of it, AIS wasn't particularly intended for collision avoidance when designed.

American paranoia after 9/11 was a big driver to its adoption. (It was already being designed before then, but American insistence on monitoring everything around them reportedly sped things up quite a bit.)

The means of propulsion would need to be automated to be of any value. You could connect a switch on the gear shift of your engine to your nav lights to set them correctly. No electronics, just a simple switch... so why not?

I did something very similar on our previous boat . A relay in the engine wiring ensured that, if the bow and stern lights were already on, the steaming light would come on when the engine was running and go off when it was stopped. Of course technically it should have been controlled by the gears, but I wasn't in the habit of running the engine in neutral...

Pete

 

[prv]

While it's probably beyond this forum, one wonders why a field for 'type' was included (and not means of propulsion, current activity) in the design phase.

Simple cockup and design-by-committee in the Class B design phase, I assume. They probably had a certain number of bytes to play with to squeeze in between the existing Class A messages, and prioritised something else ahead of this. As I said earlier, I do think this was a mistake given the diverse range of vessels using Class B.

Pete