AIS toggle between sail/power?

[GHA]

I think it'd be a waste of time anyway, about as reliable as a motoring cone. I regularly see tugs and pilot boats on AIS with nav status "at anchor", but clearly underway.

Wouldn't agree there, I think arcbennet deserves some kudos for showing some seamanship and trying to do the right thing rather than the answers like "why bother, no one else does/ no one looks anyway" .

Not all boats set their user ais data correctly but many do, and it can be very useful info for the rest of us.

 

[ghostlymoron]

Anything that relies on manual input is intrinsically unreliable. You often come across obvious wrong information on boat finder and live ais.

 

[GHA]

Anything that relies on manual input is intrinsically unreliable. .

Indeed, why even bother with parts C & D of the Col Regs

 

[arcbennett]

Thank you to all who have contributed responses to my query. I entirely agree that AIS is indeed merely an aid with regard to safe navigation and collision avoidance, but I can't agree that it's unimportant. To my mind, we the boating community should aspire to having a professional approach to all that we do at sea; sending incorrect and/or confusing information to other users is, as has been pointed out, poor seamanship.

Thank you for the generic information on how to change software settings on those active AIS that have this facility. But I don't want to be fiddling with software settings in rough conditions - the IT wizzes might find it easy, but I know I'd far rather have 'under sail / under power' switch(es). As indeed we do for our nav lights.

It seems the answer to my question is 'no' with regard to what's currently on the market.

 

[prv]

I don't want to be fiddling with software settings in rough conditions - the IT wizzes might find it easy, but I know I'd far rather have 'under sail / under power' switch(es). As indeed we do for our nav lights.

I might fairly be described as an "IT whizz" (I'm a professional software engineer), but I heartily agree with you here

In the previous thread, before I'd realised that Class B can't do Nav Status, I'd called for AIS boxes to have terminals for dedicated switches. Default to "making way under power" for those who didn't want to bother with additional wiring, but combined with the power supply and the "silent" terminals that many do have, I'd have fitted a simple rotary switch for "Off", "Silent", "Power", and "Sail" - right next to the similar switch I made for my nav lights:

It seems the answer to my question is 'no' with regard to what's currently on the market.

Sadly it's not just about the current market, but a fundamental limitation of the protocol.

Pete

 

[arcbennett]

Thanks prv Pete.
As I understand it, if I buy a Class B trans receiver, it will not be transmitting anything about my means of propulsion. Far better that than the wrong information.
But I'm still left with a lingering doubt. I'll need to look again more closely at the data displayed by my AIS receiver; but I'm pretty sure that from vessels that might reasonably (due to their size - ie. sailing boats) be assumed to have a Class B system, my tote has been informing me if they are a sailing vessel (or power driven).
Alan.

 

[PaulRainbow]

but I'm pretty sure that from vessels that might reasonably (due to their size - ie. sailing boats) be assumed to have a Class B system, my tote has been informing me if they are a sailing vessel (or power driven).
Alan.

Class B does transmit vessel type, but that doesn't tell you how it's being propelled.

 

[PaulRainbow]

Wouldn't agree there, I think arcbennet deserves some kudos for showing some seamanship and trying to do the right thing rather than the answers like "why bother, no one else does/ no one looks anyway" .

Not all boats set their user ais data correctly but many do, and it can be very useful info for the rest of us.

It's a good idea in principle, but i simply think that because it's user input it's too unreliable to be of any real use. If it was used as much as motoring cones....................

 

[prv]

I'll need to look again more closely at the data displayed by my AIS receiver; but I'm pretty sure that from vessels that might reasonably (due to their size - ie. sailing boats) be assumed to have a Class B system, my tote has been informing me if they are a sailing vessel (or power driven).

A Class B vessel uses message 24B to say various things about itself:

The "Type of ship and cargo type" field can be set to number 36 to mean "sailing vessel". But this is a static description of the type of vessel, not whether it is currently sailing or under power. It's not meant to be changed on a routine basis, and as far as I know no equipment allows it to be.

The current state is given in the "Navigational Status" field of Message 1:

...but this message is only emitted by Class A transmitters.

If I had a Class B AIS transmitter, I think my best compromise would be to set "Type of ship" to "36 - sailing vessel" to indicate the possibility that I might be sailing, and let other watchkeepers determine my actual state in the traditional visual manner.

Pete

 

[[70521]]

Why do you feel it necessary to transmit that you are under sail or motor? The maximum speed will be about the same.

 

[PaulRainbow]

If I had a Class B AIS transmitter, I think my best compromise would be to set "Type of ship" to "36 - sailing vessel" to indicate the possibility that I might be sailing, and let other watchkeepers determine my actual state in the traditional visual manner.

Pete

That makes sense Pete.

You could have peer through the bins and see if he's showing a motoring cone

 

[PaulRainbow]

Why do you feel it necessary to transmit that you are under sail or motor? The maximum speed will be about the same.

Nav status effects who is stand on/give way.

 

[prv]

Why do you feel it necessary to transmit that you are under sail or motor? The maximum speed will be about the same.

Because it might determine whether another vessel is required to hold her course or alter it.

Large vessels like to have each pass set up many miles before it happens, and regardless of what the MCA says, they increasingly use AIS to do it.

Pete

 

[jakeroyd]

Apologies for not reading the whole thread but going back to the OP's question I think what a great idea in terms of if two sailing vessels are approaching each other the time and severity of a potential collision are very different from that involving a power driven vessel.
By this I mean not a motoring yacht but a power boat moving at say 12k.

 

[{151760}]

Wouldn't agree there, I think arcbennet deserves some kudos for showing some seamanship and trying to do the right thing rather than the answers like "why bother, no one else does/ no one looks anyway" .

Not all boats set their user ais data correctly but many do, and it can be very useful info for the rest of us.

As we've established that Class B transmitters don't send Navigation Status messages, but some software will populate that field with false information, surely the seaman like thing is to treat that particular item with deep suspicion and rely on eyeballs?

 

[Bru]

As we've established that Class B transmitters don't send Navigation Status messages, but some software will populate that field with false information, surely the seaman like thing is to treat that particular item with deep suspicion and rely on eyeballs?

Software will only "populate" dynamic status information on vessel tracking websites

The information will not, and cannot, be available on AIS receivers

 

[{151760}]

Software will only "populate" dynamic status information on vessel tracking websites

The information will not, and cannot, be available on AIS receivers

Not according to the OP.
Actually, I may have misunderstood his first post. I thought he said that his receiver showed the Status message. But perhaps it doesn't.
Anyway, I now know a lot more about AIS than I did yesterday!

 

[arcbennett]

Thanks prv Pete for posting those two tables; I'm beginning to see why I have been puzzled with respect to information stemming from Class B transmitters.

It seems I have let the field 'Type of ship and cargo type' confuse me (and maybe others). As you say, this field merely indicates type - and not the current means of propulsion (or indeed, activity eg. power driven vessel engaged in fishing (or not)). I suspect that I am not the only one who has misinterpreted this extraneous information.

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. As far as safe navigation is concerned, type is an irrelevance. Type has no bearing on the col regs; whereas current means of propulsion and/or activity most certainly do.
Alan.

 

[Bru]

Type may have little bearing on Colregs but AIS was not developed as and is not purely a collision avoidance system

Type of vessel and cargo are data of significance to enforcement agencies, port authorities etc

And when AIS war originally conceived, it was not intended for small leisure vessels. Class B is basically an afterthought with the quantify and frequency of data transmitted cut back, compared to Class A, to a minium due to the limited availability of transmission capacity inherent in the AIS system

 

[ShinyShoe]

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. As far as safe navigation is concerned, type is an irrelevance. Type has no bearing on the col regs; whereas current means of propulsion and/or activity most certainly do.
Alan.

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!

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?