Empathy List Archives

JB

Jim Barrentine

Fri, Aug 23, 2013 10:23 PM

On my AIS, a target first shows up identified only by MMSI. After several minutes the vessel name appears. Is this the way all AIS receivers work? Is there a standard for the frequency with which the name is transmitted?

Sent from my iPad
Jim Barrentine

On my AIS, a target first shows up identified only by MMSI. After several minutes the vessel name appears. Is this the way all AIS receivers work? Is there a standard for the frequency with which the name is transmitted? Sent from my iPad Jim Barrentine

P

peterbb

Fri, Aug 23, 2013 10:45 PM

There are two types of AIS messages of concern here.

The Navigational message has the MMSI, course, speed, rate of turn (for Class A) and other data that changes as the vessel moves.

The Static Data message contains MMSI, vessel name, dimensions and destination (for Class A) and some other data The Navigational Status (underway, sailing, anchored, etc.) is manually entered, and not always updated promptly - I've seen vessels leaving an anchorage at 10 knots, still claiming to be anchored..

The Navigation message is sent ever 10 seconds or so, depending on vessel speed, for Class A vessels underway, and every 30 seconds (I think) for Class B. It is sent less often for vessels at anchor or moored. The Static Data message is sent every six minutes for Class B - don't recall timing for Class A, but it may also be six minutes.

Someone suggested looking at MarineTraffic.com to confirm the reported speed. It appears that the free MarineTraffic data is delayed by several minutes. Shipfinder.com appears to be much closer to real time.

----- Original Message -----
From: Jim Barrentine jbarrentine@ipa.net
To: Trawler World List trawlers@lists.trawlering.com
Sent: Fri, 23 Aug 2013 16:23:29 -0600 (MDT)
Subject: T&T: Another AIS Question

On my AIS, a target first shows up identified only by MMSI. After several minutes the vessel name appears. Is this the way all AIS receivers work? Is there a standard for the frequency with which the name is transmitted?

Sent from my iPad
Jim Barrentine

There are two types of AIS messages of concern here. The Navigational message has the MMSI, course, speed, rate of turn (for Class A) and other data that changes as the vessel moves. The Static Data message contains MMSI, vessel name, dimensions and destination (for Class A) and some other data The Navigational Status (underway, sailing, anchored, etc.) is manually entered, and not always updated promptly - I've seen vessels leaving an anchorage at 10 knots, still claiming to be anchored.. The Navigation message is sent ever 10 seconds or so, depending on vessel speed, for Class A vessels underway, and every 30 seconds (I think) for Class B. It is sent less often for vessels at anchor or moored. The Static Data message is sent every six minutes for Class B - don't recall timing for Class A, but it may also be six minutes. Someone suggested looking at MarineTraffic.com to confirm the reported speed. It appears that the free MarineTraffic data is delayed by several minutes. Shipfinder.com appears to be much closer to real time. ----- Original Message ----- From: Jim Barrentine <jbarrentine@ipa.net> To: Trawler World List <trawlers@lists.trawlering.com> Sent: Fri, 23 Aug 2013 16:23:29 -0600 (MDT) Subject: T&T: Another AIS Question On my AIS, a target first shows up identified only by MMSI. After several minutes the vessel name appears. Is this the way all AIS receivers work? Is there a standard for the frequency with which the name is transmitted? Sent from my iPad Jim Barrentine _______________________________________________

AT

Al Thomason

Sat, Aug 24, 2013 1:55 AM

<SNIP>

" Someone suggested looking at MarineTraffic.com to confirm the reported
speed. It appears that the free MarineTraffic data is delayed by several
minutes. Shipfinder.com appears to be much closer to real time."

Only if you pay for the subscription fee, else it is a 12 hour delay:
http://www.shipfinder.com/main/server

-al-

Viking Star
45' Monk Sr. / McQueen
mvVikingStar.blogspot.com

<SNIP> " Someone suggested looking at MarineTraffic.com to confirm the reported speed. It appears that the free MarineTraffic data is delayed by several minutes. Shipfinder.com appears to be much closer to real time." Only if you pay for the subscription fee, else it is a 12 hour delay: http://www.shipfinder.com/main/server -al- Viking Star 45' Monk Sr. / McQueen mvVikingStar.blogspot.com

P

peterbb

Sat, Aug 24, 2013 3:28 AM

Sorry - I didn't realize there are two tracking sites with almost identical names. The one I meant is shipfinder.co (no "m")(they also have an iPhone app, and the same group also has a planefinder app).

shipfinder.com (with an "m") is different, and expensive...

----- Original Message -----
From: Al Thomason thomason.al@gmail.com
To: 'Trawler World List' trawlers@lists.trawlering.com
Sent: Fri, 23 Aug 2013 19:55:17 -0600 (MDT)
Subject: Re: T&T: Another AIS Question

<SNIP>

" Someone suggested looking at MarineTraffic.com to confirm the reported
speed. It appears that the free MarineTraffic data is delayed by several
minutes. Shipfinder.com appears to be much closer to real time."

Only if you pay for the subscription fee, else it is a 12 hour delay:
http://www.shipfinder.com/main/server

-al-

Viking Star
45' Monk Sr. / McQueen
mvVikingStar.blogspot.com

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Trawlers & Trawlering and T&T are trademarks of Water World
Productions. Unauthorized use is prohibited.

Sorry - I didn't realize there are two tracking sites with _almost_ identical names. The one I meant is shipfinder.co (no "m")(they also have an iPhone app, and the same group also has a planefinder app). shipfinder.com (with an "m") is different, and expensive... ----- Original Message ----- From: Al Thomason <thomason.al@gmail.com> To: 'Trawler World List' <trawlers@lists.trawlering.com> Sent: Fri, 23 Aug 2013 19:55:17 -0600 (MDT) Subject: Re: T&T: Another AIS Question <SNIP> " Someone suggested looking at MarineTraffic.com to confirm the reported speed. It appears that the free MarineTraffic data is delayed by several minutes. Shipfinder.com appears to be much closer to real time." Only if you pay for the subscription fee, else it is a 12 hour delay: http://www.shipfinder.com/main/server -al- Viking Star 45' Monk Sr. / McQueen mvVikingStar.blogspot.com _______________________________________________ http://lists.trawlering.com/mailman/listinfo/trawlers_lists.trawlering.com To unsubscribe or modify your subscription options (get password, change email address, etc) go to: http://lists.trawlering.com/mailman/listinfo/trawlers_lists.trawlering.com Trawlers & Trawlering and T&T are trademarks of Water World Productions. Unauthorized use is prohibited.

BM

Bob McLeran

Sat, Aug 24, 2013 1:12 PM

The bottom line is that no web sage is a good substitute for a dedicated AIS unit onboard if you really want that additional data to help navigate.

Real world. MarineTraffic.com data is delayed only a few minutes - no need to pay for anything. The "problem" is that in some areas class B AIS (pleasure boats) will not get displayed on the web site. The data must be relayed to the site by repeater stations; no repeater, no data to the site. The only way to ensure your position is displayed on the web sage it to self-report using their app, and that is dependent on having an internet connection. OTOH, AIS is a safety/navigation tool, so the primary reason for having AIS at all is in furtherance of that objective, not to keep your friends informed as to your location at any given moment and the primary objective works via VHF not via the internet! The web site explains how the AIS system interfaces with the site.

Sent from my Droid4 phone with K-9 Mail. Please excuse my brevity.
Blog: MVSanderling.net/blog
Web: cruising.mvsanderling.net
Currently southbound on Lake Michigan

Al Thomason thomason.al@gmail.com wrote:

<SNIP>

" Someone suggested looking at MarineTraffic.com to confirm the
reported
speed. It appears that the free MarineTraffic data is delayed by
several
minutes. Shipfinder.com appears to be much closer to real time."

Only if you pay for the subscription fee, else it is a 12 hour delay:
http://www.shipfinder.com/main/server

The bottom line is that no web sage is a good substitute for a dedicated AIS unit onboard if you really want that additional data to help navigate. Real world. MarineTraffic.com data is delayed only a few minutes - no need to pay for anything. The "problem" is that in some areas class B AIS (pleasure boats) will not get displayed on the web site. The data must be relayed to the site by repeater stations; no repeater, no data to the site. The only way to ensure your position is displayed on the web sage it to self-report using their app, and that is dependent on having an internet connection. OTOH, AIS is a safety/navigation tool, so the primary reason for having AIS at all is in furtherance of that objective, not to keep your friends informed as to your location at any given moment and the primary objective works via VHF not via the internet! The web site explains how the AIS system interfaces with the site. -- Sent from my Droid4 phone with K-9 Mail. Please excuse my brevity. Blog: MVSanderling.net/blog Web: cruising.mvsanderling.net Currently southbound on Lake Michigan Al Thomason <thomason.al@gmail.com> wrote: ><SNIP> > >" Someone suggested looking at MarineTraffic.com to confirm the >reported >speed. It appears that the free MarineTraffic data is delayed by >several >minutes. Shipfinder.com appears to be much closer to real time." > >Only if you pay for the subscription fee, else it is a 12 hour delay: >http://www.shipfinder.com/main/server >

AT

Al Thomason

Sat, Aug 24, 2013 4:18 PM

The OP was looking for a way to verify their AIS transmitter, using one of these web based AIS services is a nice tool for that. But you are correct, for on-board nothing beats an AIS receiver - and given their low cost these days it is a good addition. We tend to use AIS daily in our travels, mostly to stay well away from fast moving ferry's, and also when looking to transit a VTS lane.

However, there does seem to be some activity for IP based (ala Web or app hosted) AIS services, something calls AIS-E, as mentioned here: http://www.panbo.com/archives/2012/08/class_e_ais_will_it_be_huge.html

-al-

Viking Star
45' Monk Sr. / McQueen
mvVikingStar.blogspot.com

-----Original Message-----
From: Bob McLeran [mailto:bob@mvsanderling.net]
Sent: Saturday, August 24, 2013 6:13 AM
To: Al Thomason; 'Trawler World List'
Subject: Re: T&T: Another AIS Question

The bottom line is that no web sage is a good substitute for a dedicated AIS unit onboard if you really want that additional data to help navigate.

Real world. MarineTraffic.com data is delayed only a few minutes - no need to pay for anything. The "problem" is that in some areas class B AIS (pleasure boats) will not get displayed on the web site. The data must be relayed to the site by repeater stations; no repeater, no data to the site. The only way to ensure your position is displayed on the web sage it to self-report using their app, and that is dependent on having an internet connection. OTOH, AIS is a safety/navigation tool, so the primary reason for having AIS at all is in furtherance of that objective, not to keep your friends informed as to your location at any given moment and the primary objective works via VHF not via the internet! The web site explains how the AIS system interfaces with the site.

Sent from my Droid4 phone with K-9 Mail. Please excuse my brevity.
Blog: MVSanderling.net/blog
Web: cruising.mvsanderling.net
Currently southbound on Lake Michigan

The OP was looking for a way to verify their AIS transmitter, using one of these web based AIS services is a nice tool for that. But you are correct, for on-board nothing beats an AIS receiver - and given their low cost these days it is a good addition. We tend to use AIS daily in our travels, mostly to stay well away from fast moving ferry's, and also when looking to transit a VTS lane. However, there does seem to be some activity for IP based (ala Web or app hosted) AIS services, something calls AIS-E, as mentioned here: http://www.panbo.com/archives/2012/08/class_e_ais_will_it_be_huge.html -al- Viking Star 45' Monk Sr. / McQueen mvVikingStar.blogspot.com -----Original Message----- From: Bob McLeran [mailto:bob@mvsanderling.net] Sent: Saturday, August 24, 2013 6:13 AM To: Al Thomason; 'Trawler World List' Subject: Re: T&T: Another AIS Question The bottom line is that no web sage is a good substitute for a dedicated AIS unit onboard if you really want that additional data to help navigate. Real world. MarineTraffic.com data is delayed only a few minutes - no need to pay for anything. The "problem" is that in some areas class B AIS (pleasure boats) will not get displayed on the web site. The data must be relayed to the site by repeater stations; no repeater, no data to the site. The only way to ensure your position is displayed on the web sage it to self-report using their app, and that is dependent on having an internet connection. OTOH, AIS is a safety/navigation tool, so the primary reason for having AIS at all is in furtherance of that objective, not to keep your friends informed as to your location at any given moment and the primary objective works via VHF not via the internet! The web site explains how the AIS system interfaces with the site. -- Sent from my Droid4 phone with K-9 Mail. Please excuse my brevity. Blog: MVSanderling.net/blog Web: cruising.mvsanderling.net Currently southbound on Lake Michigan

AT

Al Thomason

Sat, Aug 24, 2013 4:18 PM

Nice! I like that Apple app where you take a photo of the ship and it pops on the screen info!!! (Too bad I have an Android based tablet)

After a little digging, it APPEARS that all these tracking services use the same database of collected AIS info: http://www.aishub.net/ (At least the two mentioned below both use the same script for collecting info from volunteers: aisdispatcher ) AIShub.net has a link to yet another viewing site: http://www.vesselfinder.com/

Their website also gives a list of active receiving stations: http://www.aishub.net/ais-tracking-statistics.html as well as other stats.

Though anyone can get a feed (one only needs to supply at least one source), there seems to be no restriction on how the data is used after that - timeliness of response, history of data, or fees charged. http://www.aishub.net/ais-tracking-join-us.html Buyer beware!

These mobile apps, providing they can give some level of real-time response, sure would be nice for folks like Kayakers - and I do know of a few delivery folks who include one on their carry-aboard nav gear. For use while they are in cell-phone range.

-al-

Viking Star
45' Monk Sr. / McQueen
mvVikingStar.blogspot.com

-----Original Message-----
From: peterbb [mailto:peterbb@telus.net]
Sent: Friday, August 23, 2013 8:29 PM
To: Al Thomason
Cc: 'Trawler World List'
Subject: Re: T&T: Another AIS Question

Sorry - I didn't realize there are two tracking sites with almost identical names. The one I meant is shipfinder.co (no "m")(they also have an iPhone app, and the same group also has a planefinder app).

shipfinder.com (with an "m") is different, and expensive...

Nice! I like that Apple app where you take a photo of the ship and it pops on the screen info!!! (Too bad I have an Android based tablet) After a little digging, it APPEARS that all these tracking services use the same database of collected AIS info: http://www.aishub.net/ (At least the two mentioned below both use the same script for collecting info from volunteers: aisdispatcher ) AIShub.net has a link to yet another viewing site: http://www.vesselfinder.com/ Their website also gives a list of active receiving stations: http://www.aishub.net/ais-tracking-statistics.html as well as other stats. Though anyone can get a feed (one only needs to supply at least one source), there seems to be no restriction on how the data is used after that - timeliness of response, history of data, or fees charged. http://www.aishub.net/ais-tracking-join-us.html Buyer beware! These mobile apps, providing they can give some level of real-time response, sure would be nice for folks like Kayakers - and I do know of a few delivery folks who include one on their carry-aboard nav gear. For use while they are in cell-phone range. -al- Viking Star 45' Monk Sr. / McQueen mvVikingStar.blogspot.com -----Original Message----- From: peterbb [mailto:peterbb@telus.net] Sent: Friday, August 23, 2013 8:29 PM To: Al Thomason Cc: 'Trawler World List' Subject: Re: T&T: Another AIS Question Sorry - I didn't realize there are two tracking sites with _almost_ identical names. The one I meant is shipfinder.co (no "m")(they also have an iPhone app, and the same group also has a planefinder app). shipfinder.com (with an "m") is different, and expensive...