AIS

[sailaboutvic]

Yealm not sure why your getting so wind up about this .
You like it and find it useful , other like my self don't find it so useful . I find it a pain at times All them blop coving up chart info .
But my co skipper like it when we night sailing combin with the radar , and as she on watch for three to four hours at a time and save her waking me that's cool ,
I am one of tbese lucky guy I can look at a ship and know if and how it's going to pass,
that the way I learned many years ago .
But hey if it help you to stay safe , it can only be a good thing .

I bet if we took away all the AIS. Plotter, GPS , forward finders there be a lot less boats about and more confident Sailors .

 

[Praxinoscope]

Are you sure your AIS is working correctly? It's not a particularly busy area, but I can see about 7 AIS targets in Cardigan Bay right now. To only see one in two months seems a bit odd.

Just had a look on AIS tracking site and yes there are plenty of targets 30 to 40 miles South of us, which is what I usually experience, very rarely do we see an AIS target in our area.

 

[Yealm]

ps a thought - wonder if it would be a helpful feature on chartplotters for the user to select ‘only display AIS targets that are a potential collision threat to me’ to reduce screen clutter in busy waters?

 

[RichardS]

ps a thought - wonder if it would be a helpful feature on chartplotters for the user to select ‘only display AIS targets that are a potential collision threat to me’ to reduce screen clutter in busy waters?

You can tell OpenCPN to dispense with non-critical targets if there are more than a user-determined total number of targets on screen. I don't know if modern plotters can do something similar.

Richard

 

[TSB240]

ps a thought - wonder if it would be a helpful feature on chartplotters for the user to select ‘only display AIS targets that are a potential collision threat to me’ to reduce screen clutter in busy waters?

Screen clutter is really not a problem in our area just north of Cardigan Bay. I do find the AIS collision display for open CPN is exceptional. With open CPN you can attenuate the targets. This basically means that anything that might not be a risk can be decluttered from your display. It really is time the marine suppliers caught up with this.

There is also an interesting argument put forward in the Open CPN manual for mounting your class B transmitter aerial lower down.This could increase your chance of broadcasting and updating your AIS position to class A collision risks in your vicinity. Your transmissions will not potentially be blocked by priority class A transmissions from further afield that do not present a danger.
In a cluttered screen full of Class B transmitters yours might get a transmission slot because your receiver is only receiving a few local class A signals whereas other local Class Bs might still be waiting for a clear slot as they are blocked by receiving the class As at greater distance.

AIS use is evolving and is no magic wand to navigation in poor visibility it is just another spanner in the toolbox

 

[Uricanejack]

Here is some. Google Assisted Plagiarising of an article about AIS assisted collisions. Refers to an MAIB report, which might be an interesting read.

AIS assisted collisions
06 November 2014

The term "VHF assisted collision" is not new.
It is used when an officer of the watch negotiates actions to avoid a collision with another vessel over the radio rather than following the Collision Regulations (Colregs), but ends up colliding with the vessel, usually because of miscommunication between the parties or an agreement to maneuver vessels in a manner contravening the Colregs.
The UK Marine Accident Investigation Board (MAIB) has recently published its report on the collision between the RICKMERS DUBAI and WALCON WIZARD, which was being towed by the KINGSTON in the Dover Straits in January 2014. The authors of the report heavily criticise the over-reliance by the navigating officer on RICKMERS DUBAI on the ship's Automatic Identification System (AIS) equipment.
AIS was phased into commercial shipping approximately 10 years ago, with security concerns being the main driver behind its implementation. Air traffic control has employed a similar system for decades and this system, together with radar, forms the basis of the control of aircraft.
Like all other equipment available to the navigating officer, AIS must be used with caution and, most importantly, in conjunction with other equipment. Crosschecking the information available from the AIS is especially important because of the high risk of errors that may be contained within. Unlike other sources of information, such as visual and radar, the correct functioning of the AIS relies on the equipment on other vessels performing correctly. This is not just confined to the AIS system itself, but also to all the navigational equipment that feeds the system. Of all the information available to the officer of the watch, that which is obtained from the AIS may often be the least reliable.
The MAIB report identifies several factors that contributed to the collision, however it was the reliance by the navigator on RICKMERS DUBAI solely on AIS information for collision avoidance, which contributed most. It is easy to see why, given that neither KINGSTON nor WALCON WIZARD were transmitting AIS data at the time.
The full report can be obtained by following the link below.
Rickmers Dubai Vs Walcon Wizard & Kingston

The same google search also came up with

MGN 342. Its quite long and quite detailed.

 

[AntarcticPilot]

Surely it is not a choice . . . radar reflectors just work, require no power (unless See-Me or similar) and are a bit of a no-brainer.

AIS is very reassuring to have and undoubtedly increases safety in fog . . . much easier to fit for smaller boats than radar, and easier to use, BUT as others have pointed out you need ot be aware that not everything out there shows on AIS.

If you are getting an AIS then a transceiver (transmit as well) is not a lot more expensive these days and seems a bit of a no-brainer.


- W

Well, I'm afraid that according to the Ouzo MAIB report, passive radar reflectors don't "just work". Some types work to a limited extent, but these tend to be the big, heavy and expensive ones that few people fit! I have a SeaMe, and the active transponders come out of that report pretty well, but passive reflectors came out ranging between "useless" and "almost good enough, providing you aren't heeling".

My own experience with much larger corner reflectors in a different context is that they need to be made to a surprisingly high precision to be effective, and that they also need to be BIG to be effective.

 

[Yealm]

Screen clutter is really not a problem in our area just north of Cardigan Bay. I do find the AIS collision display for open CPN is exceptional. With open CPN you can attenuate the targets. This basically means that anything that might not be a risk can be decluttered from your display. It really is time the marine suppliers caught up with this.

There is also an interesting argument put forward in the Open CPN manual for mounting your class B transmitter aerial lower down.This could increase your chance of broadcasting and updating your AIS position to class A collision risks in your vicinity. Your transmissions will not potentially be blocked by priority class A transmissions from further afield that do not present a danger.
In a cluttered screen full of Class B transmitters yours might get a transmission slot because your receiver is only receiving a few local class A signals whereas other local Class Bs might still be waiting for a clear slot as they are blocked by receiving the class As at greater distance.

AIS use is evolving and is no magic wand to navigation in poor visibility it is just another spanner in the toolbox

That’s really interesting. It does seem to have great functionality likel showing CPA position visually so you know if beneficial to speed up or slow down.

Do you use open CPN as your primary chartplotter? Or do you have Navionics or something else and just use open CPN for it’s AIS functionality? As I understand it, the limitations of open CPN are that it is cabin based (ie on a laptop) and can’t use vector charts?

 

[Yealm]

Here is some. Google Assisted Plagiarising of an article about AIS assisted collisions. Refers to an MAIB report, which might be an interesting read.

AIS assisted collisions
06 November 2014

The term "VHF assisted collision" is not new.
It is used when an officer of the watch negotiates actions to avoid a collision with another vessel over the radio rather than following the Collision Regulations (Colregs), but ends up colliding with the vessel, usually because of miscommunication between the parties or an agreement to maneuver vessels in a manner contravening the Colregs.
The UK Marine Accident Investigation Board (MAIB) has recently published its report on the collision between the RICKMERS DUBAI and WALCON WIZARD, which was being towed by the KINGSTON in the Dover Straits in January 2014. The authors of the report heavily criticise the over-reliance by the navigating officer on RICKMERS DUBAI on the ship's Automatic Identification System (AIS) equipment.
AIS was phased into commercial shipping approximately 10 years ago, with security concerns being the main driver behind its implementation. Air traffic control has employed a similar system for decades and this system, together with radar, forms the basis of the control of aircraft.
Like all other equipment available to the navigating officer, AIS must be used with caution and, most importantly, in conjunction with other equipment. Crosschecking the information available from the AIS is especially important because of the high risk of errors that may be contained within. Unlike other sources of information, such as visual and radar, the correct functioning of the AIS relies on the equipment on other vessels performing correctly. This is not just confined to the AIS system itself, but also to all the navigational equipment that feeds the system. Of all the information available to the officer of the watch, that which is obtained from the AIS may often be the least reliable.
The MAIB report identifies several factors that contributed to the collision, however it was the reliance by the navigator on RICKMERS DUBAI solely on AIS information for collision avoidance, which contributed most. It is easy to see why, given that neither KINGSTON nor WALCON WIZARD were transmitting AIS data at the time.
The full report can be obtained by following the link below.
Rickmers Dubai Vs Walcon Wizard & Kingston

The same google search also came up with

MGN 342. Its quite long and quite detailed.

Is AIS mandatory for all aircraft?

 

[RichardS]

That’s really interesting. It does seem to have great functionality likel showing CPA position visually so you know if beneficial to speed up or slow down.

Do you use open CPN as your primary chartplotter? Or do you have Navionics or something else and just use open CPN for it’s AIS functionality? As I understand it, the limitations of open CPN are that it is cabin based (ie on a laptop) and can’t use vector charts?

I use OpenCPN on my tablet for detailed AIS collision avoidance.

The tablet sits by the helm and if I see anything of concern, either by eye or on the chartplotter display, I just pick up the tablet, tap the screen, and see what OpenCPN has to say.

I was on a direct collision with a large powerboat a few weeks ago although it was about 5 miles away. The CPA vector showed zero metres clearance so I tapped the autopilot to steer 1 degree to starboard and, within 10 seconds, the CPA vector extended to 10 metres or something. Tap 1 degree back to port and it closes down to zero again.

If you were the give way boat you could, in theory, decide whether you want the stand-on vessel to pass behind or ahead of you and by what margin and then tap in the course to achieve your exact desired result, even though that will not happen for another 30 minutes or whatever.

Of course, in the real world, there are too many other variables and deciding that the give-way vessel should pass ahead might not be the best idea .... but the system is very clever.

In this case, I was the stand-on vessel so I stood on and a couple of miles out I saw the mobo make the necessary correction to his course on the screen before I could clearly see what he was doing by eye.

Richard

 

[Yealm]

I use OpenCPN on my tablet for detailed AIS collision avoidance.

The tablet sits by the helm and if I see anything of concern, either by eye or on the chartplotter display, I just pick up the tablet, tap the screen, and see what OpenCPN has to say.

I was on a direct collision with a large powerboat a few weeks ago although it was about 5 miles away. The CPA vector showed zero metres clearance so I tapped the autopilot to steer 1 degree to starboard and, within 10 seconds, the CPA vector extended to 10 metres or something. Tap 1 degree back to port and it closes down to zero again.

If you were the give way boat you could, in theory, decide whether you want the stand-on vessel to pass behind or ahead of you and by what margin and then tap in the course to achieve your exact desired result, even though that will not happen for another 30 minutes or whatever.

Of course, in the real world, there are too many other variables and deciding that the give-way vessel should pass ahead might not be the best idea .... but the system is very clever.

In this case, I was the stand-on vessel so I stood on and a couple of miles out I saw the mobo make the necessary correction to his course on the screen before I could clearly see what he was doing by eye.

Richard

Cool !
I guess you use WiFi to get the AIS data to the tablet? Do you know if it works on an iPad ?

 

[RichardS]

Cool !
I guess you use WiFi to get the AIS data to the tablet? Do you know if it works on an iPad ?

Yes .... I use it on an Android tablet and the data arrives by wifi so no troublesome wires involved. Unfortunately, OpenCPN is not available for iPads, I'm afraid.

Richard

 

[Yealm]

Yes .... I use it on an Android tablet and the data arrives by wifi so no troublesome wires involved. Unfortunately, OpenCPN is not available for iPads, I'm afraid.

Richard

Many thanks

 

[BrianH]

Do you use open CPN as your primary chartplotter? Or do you have Navionics or something else and just use open CPN for it’s AIS functionality? As I understand it, the limitations of open CPN are that it is cabin based (ie on a laptop) and can’t use vector charts?

With my motorsailer I have an older Garmin plotter on the chart table in the dog house steering position that cannot display AIS targets and the screen is too small anyway. This contains all my waypoints and is the primary navigation plotter.

Below on the port-side chart table sits a Windows 10 laptop running OpenCPN connected to the AIS transceiver and is actually visible from the steering position by glancing down into the cabin. Alarms from CPA threats are audible enough to bring me down to check while the wheel-pilot takes over.

I have both raster and vector charts in the PC and can switch through any mix from the OCPN chart menu bar along the bottom of the screen that shows all available, relevant charts, raster and vector, for the sea area I am in. Accepted chart formats are shown in the manual here.

 

[GHA]

I have both raster and vector charts in the PC and can switch through any mix from the OCPN chart menu bar along the bottom of the screen that shows all available, relevant charts, raster and vector, for the sea area I am in. Accepted chart formats are shown in the manual here.

​

For those unfamiliar with OpenCPN (it's great! ) , you can also set chart groups so with a right click mouse menu view just google earth or cm93 or raster etc.

 

[Yealm]

For those unfamiliar with OpenCPN (it's great! ) , you can also set chart groups so with a right click mouse menu view just google earth or cm93 or raster etc.

What vector charts can you use with it for the UK? Eg Navionics, Garmin possible?

 

[GHA]

What vector charts can you use with it for the UK? Eg Navionics, Garmin possible?

Neither of those, but these are available.
http://o-charts.org/shop/index.php?id_category=8&controller=category&id_lang=4

And visit my harbour on a laptop if you prefer raster. Worldwide older cmp3 charts are knocking about on the internet (and pretty much every cruising boat ) but technically breaking copyright.

Really easy to create harbour charts from google satellite images, just a few clicks in a plugin. Can be very useful.

The AIS display on Opencpn must be as good as anything else available, plus the weather options are excellent.

You can actually convert web navionics into raster but it's of a runaround. Maybe a little bit naughty too.

 

[Yealm]

Neither of those, but these are available.
http://o-charts.org/shop/index.php?id_category=8&controller=category&id_lang=4

And visit my harbour on a laptop if you prefer raster. Worldwide older cmp3 charts are knocking about on the internet (and pretty much every cruising boat ) but technically breaking copyright.

Really easy to create harbour charts from google satellite images, just a few clicks in a plugin. Can be very useful.

The AIS display on Opencpn must be as good as anything else available, plus the weather options are excellent.

You can actually convert web navionics into raster but it's of a runaround. Maybe a little bit naughty too.

Thanks! It does seem really great software.

 

[Lucky Duck]

"Barfleur" - the Poole to CIs ferry - while perfectly visible to the eye and radar was invisible are far as AIS was concerned near Anvil point yesterday morning....

 

[BrianH]

"Barfleur" - the Poole to CIs ferry - while perfectly visible to the eye and radar was invisible are far as AIS was concerned near Anvil point yesterday morning....

Passenger ferries seem very lax about inputting their mooring status for AIS static data transmissions and, sadly - at least in the Adriatic - not transmitting any AIS signal at all, a contravention of SOLAS regulations.

Below is shown the last one I encountered approaching the island of Silba in the Dalmatian archipelago, one of the car transporter types belonging to the Jadrolinija company, whose ships I witness are frequent offenders.