I've got a laptop and thanks to the input from this board and our C34 board, I've got the BU-363 GPS puck and software for navigating.
Barry's post on another topic raises the issue of what setup(s) you're using for AIS on the laptop.
Thanks,
Stu
AIS on a laptop
- Thread starter Stu Jackson
- Start date
- Status
Barry's post on another topic raises the issue of what setup(s) you're using for AIS on the laptop.
Thanks,
Stu
Here ya go:
http://www.milltechmarine.com/Smart-Radio-SR161-AIS-Receiver_p_167.html
You can use an independent common VHF antenna or an 'amplified VHF antenna splitter' from the above website.
http://www.milltechmarine.com/Smart-Radio-SR161-AIS-Receiver_p_167.html
You can use an independent common VHF antenna or an 'amplified VHF antenna splitter' from the above website.
What I'm Using
Stu, I'm using a Smart Radio single channel (ie cheap) AIS receiver which shares a second VHF's separate antenna via an A B two way coax switch. The second VHF is a below-deck back up and a handy one when buttoned up. I did not want to degrade the mast head antenna so it has a separate rail mount. The whole thing works very well.
This has been an evolution. First, I had the laptop-based navigation for planning. Then I added a GPS antenna to use for real-time navigation. Then I added the AIS with a rubber-ducky high-gain handheld VHF antenna. Then, I added the antenna splitter so it could share with the better antenna.
I can tell you from my experience, once you get used to it, it becomes an important part of your system and you want it (in my case) much more than you expected. To that end, if you have the same propensity, you may want to go with the two-channel unit that has a much faster refresh rate. And, I would have a separate antenna from the git-go.
Stu, I'm using a Smart Radio single channel (ie cheap) AIS receiver which shares a second VHF's separate antenna via an A B two way coax switch. The second VHF is a below-deck back up and a handy one when buttoned up. I did not want to degrade the mast head antenna so it has a separate rail mount. The whole thing works very well.
This has been an evolution. First, I had the laptop-based navigation for planning. Then I added a GPS antenna to use for real-time navigation. Then I added the AIS with a rubber-ducky high-gain handheld VHF antenna. Then, I added the antenna splitter so it could share with the better antenna.
I can tell you from my experience, once you get used to it, it becomes an important part of your system and you want it (in my case) much more than you expected. To that end, if you have the same propensity, you may want to go with the two-channel unit that has a much faster refresh rate. And, I would have a separate antenna from the git-go.
PC nav stations are so-so OK; but, they have to be kept 'below' and that requires constant climbing through the companionway. Better to have all the nav gizmos within eyeball distance of the helm .... where sometimes you need it NOW.
If you have a chartplotter that is less than 2-3 y/o, many of the AIS receivers are directly useable with many of the 'newer' chartplotters; usually not the case with plotter older than 2-3 yrs.
If you have a chartplotter that is less than 2-3 y/o, many of the AIS receivers are directly useable with many of the 'newer' chartplotters; usually not the case with plotter older than 2-3 yrs.
Stu,
Its not so much the AIS set that matters but it is what the PC navigation system does with the information that really counts.
The AIS set only sends NMEA data for the Nav Prog to decode and display.
I have been monitoring AIS from my home for the last 5 years and on board for slightly longer. Our authorities approved its use a year or two before yours did.
As I live between the two major ports of Southampton and Portsmouth I regularly see over 50 ships on screen in my study using an antenna in my loft - but many will be moored.
On board I only use a rubber dubber antenna on my coachroof for reception. It receives ships for the nearest 10 miles and, quite frankly I am not too interested in possible collisions more than half an hour hence.
On board my SeaPro program allows me to set a ring round the boat of my chosen diameter (1 mile) so that any CPA (Closest Point of Approach) which it detects closer than the set value flashes up an on screen warning and also sounds an alarm.
It also has a settable TCPA (Time to Closest Point of Approach) so you know how long you have to respond.
In our area there are many ships under way and I have crossed the Dover Strait TSS four times. This TSS averages 400 ship movements a day. AIS has been most useful to call the occasional ship to enquire if he has actually seen me. I was sailing once in less than 1 mile viz and called a ship that I was 1/2 mile dead ahead of. He said "One moment please" and went off air. A full two minutes went by before he came back with "OK I see you, I go behind". That ba***rd hadn't seen me at all!
Having AIS is an enormous stress reliever and, for preference I would always want it on. It is very useful in daylight and clear weather and, IMHO in thick weather it is essential. I do not mind that ships less than about 100' long are not required to carry AIS as I feel I can dodge these in fog and my radar should spot them anyway.
BTW Radar is counter intuitive but AIS on a Nav Prog or plotter is intuitive.]
The PC program takes the other vessel's position, course and speed from its GPS signals so this doesn't depend on the vessel's own instruments. It compares information with your boat's data and calculates CPA and TCPA immediately. The two little red dots appear on screen showing where you will be and where the ship will be at that time. Then you only need to make some alteration to either course or speed to instantly see the difference it makes, confirming whether you have made it better or worse! My program even takes account of the ship's rate of turn if it transmits this.
By comparison Radar's ARPA or MARPA will take two minutes to average its readings and show the CPA. During this time you may have yawed a bit so making the prediction useless; but you will not know this is in error.
Interestingly I can judge any other yacht at two miles and know if I will be ahead or behind when we cross. This comes as a result of 50 years plus of racing.
It doesn't work with ships. Their speed is so much greater and they show so little evidence of moving at all - until perilously close and then you know they are moving all right!
The antenna splitter is not at all clever because, though it will direct all of your VHF set's 25 watts up to the antenna, it only delivers 50% of any received signals back to the VHF because the other 50% is sent to the AIS. Even those with built in switchover relays still suffer from this defect.
The effect is you loose a third of your receiving range on your main VHF set. So you go "Mayday, Mayday" and the CG hears and says they are sending the lifeboat. But you don't hear that bit.
Regarding single channel or duplex receivers there is little to choose because mine, and one presumes all the other single channel Rx's too, use both channels by switching every 55 seconds. All AIS sets transmit on each channel sequentially, often only at a few seconds interval so, in the event that one VHF channel is blocked, there could be a delay of between 30 seconds and 1 minute in picking up a ship for the initial contact. After which it is constantly on screen. As the first contact is usually at more than 10 miles there is more than half an hour before the two vessels will come close - and your alarm, if switched on, will be sounding at least fifteen minutes before the CPA is reached.
Of course if you are travelling at 40 knots (in fog?) you will need the fastest update possible.
Whether to buy a Transciever - incorrectly called a Transponder - or just a receive only set is up to you.
I know that most ships do not have their AIS routed to their chart-plotter as the master prefers to see it on his radar. Thus they are only replicating your echo with an AIS icon on top.
Worse the class B transponders do not transmit the correct sentence that the ships AIS is set up to decode. i.e. since introduction of AIS class B all ships sets needed to be modified.
Sadly the International Maritime Organisation is sitting on their hands and has not made it mandatory that every ship's AIS set is upgraded at the annual review so, for the present at least, they might not spot you anyway. Certainly they will not see your static data so we are back to a VHF call "Vessel on my port bow etc".
Then again, when transmitting, your track will be recorded on every ships VDR (Voyage Data Recorder) for all to see - and the courts to deliberate on!
Say hello to Santa for me.
Its not so much the AIS set that matters but it is what the PC navigation system does with the information that really counts.
The AIS set only sends NMEA data for the Nav Prog to decode and display.
I have been monitoring AIS from my home for the last 5 years and on board for slightly longer. Our authorities approved its use a year or two before yours did.
As I live between the two major ports of Southampton and Portsmouth I regularly see over 50 ships on screen in my study using an antenna in my loft - but many will be moored.
On board I only use a rubber dubber antenna on my coachroof for reception. It receives ships for the nearest 10 miles and, quite frankly I am not too interested in possible collisions more than half an hour hence.
On board my SeaPro program allows me to set a ring round the boat of my chosen diameter (1 mile) so that any CPA (Closest Point of Approach) which it detects closer than the set value flashes up an on screen warning and also sounds an alarm.
It also has a settable TCPA (Time to Closest Point of Approach) so you know how long you have to respond.
In our area there are many ships under way and I have crossed the Dover Strait TSS four times. This TSS averages 400 ship movements a day. AIS has been most useful to call the occasional ship to enquire if he has actually seen me. I was sailing once in less than 1 mile viz and called a ship that I was 1/2 mile dead ahead of. He said "One moment please" and went off air. A full two minutes went by before he came back with "OK I see you, I go behind". That ba***rd hadn't seen me at all!
Having AIS is an enormous stress reliever and, for preference I would always want it on. It is very useful in daylight and clear weather and, IMHO in thick weather it is essential. I do not mind that ships less than about 100' long are not required to carry AIS as I feel I can dodge these in fog and my radar should spot them anyway.
BTW Radar is counter intuitive but AIS on a Nav Prog or plotter is intuitive.]
The PC program takes the other vessel's position, course and speed from its GPS signals so this doesn't depend on the vessel's own instruments. It compares information with your boat's data and calculates CPA and TCPA immediately. The two little red dots appear on screen showing where you will be and where the ship will be at that time. Then you only need to make some alteration to either course or speed to instantly see the difference it makes, confirming whether you have made it better or worse! My program even takes account of the ship's rate of turn if it transmits this.
By comparison Radar's ARPA or MARPA will take two minutes to average its readings and show the CPA. During this time you may have yawed a bit so making the prediction useless; but you will not know this is in error.
Interestingly I can judge any other yacht at two miles and know if I will be ahead or behind when we cross. This comes as a result of 50 years plus of racing.
It doesn't work with ships. Their speed is so much greater and they show so little evidence of moving at all - until perilously close and then you know they are moving all right!
The antenna splitter is not at all clever because, though it will direct all of your VHF set's 25 watts up to the antenna, it only delivers 50% of any received signals back to the VHF because the other 50% is sent to the AIS. Even those with built in switchover relays still suffer from this defect.
The effect is you loose a third of your receiving range on your main VHF set. So you go "Mayday, Mayday" and the CG hears and says they are sending the lifeboat. But you don't hear that bit.
Regarding single channel or duplex receivers there is little to choose because mine, and one presumes all the other single channel Rx's too, use both channels by switching every 55 seconds. All AIS sets transmit on each channel sequentially, often only at a few seconds interval so, in the event that one VHF channel is blocked, there could be a delay of between 30 seconds and 1 minute in picking up a ship for the initial contact. After which it is constantly on screen. As the first contact is usually at more than 10 miles there is more than half an hour before the two vessels will come close - and your alarm, if switched on, will be sounding at least fifteen minutes before the CPA is reached.
Of course if you are travelling at 40 knots (in fog?) you will need the fastest update possible.
Whether to buy a Transciever - incorrectly called a Transponder - or just a receive only set is up to you.
I know that most ships do not have their AIS routed to their chart-plotter as the master prefers to see it on his radar. Thus they are only replicating your echo with an AIS icon on top.
Worse the class B transponders do not transmit the correct sentence that the ships AIS is set up to decode. i.e. since introduction of AIS class B all ships sets needed to be modified.
Sadly the International Maritime Organisation is sitting on their hands and has not made it mandatory that every ship's AIS set is upgraded at the annual review so, for the present at least, they might not spot you anyway. Certainly they will not see your static data so we are back to a VHF call "Vessel on my port bow etc".
Then again, when transmitting, your track will be recorded on every ships VDR (Voyage Data Recorder) for all to see - and the courts to deliberate on!
Say hello to Santa for me.
Tim,
Not getting at you. Sorry.
Transponders transmit messages in response to received transmissions. AIS sets do not do this but SARTS and RACONS do.
Transceivers both transmit and receive without the two functions being directly linked. e.g. your VHF set - and an AIS Class B.
Unfortunately it all got off on the wrong foot several years ago and now nobody would buy a set which was NOT called a transponder.
So now AIS sets are universally known as transponders - so you were right (and, at the same time, wrong!)
Not getting at you. Sorry.
Transponders transmit messages in response to received transmissions. AIS sets do not do this but SARTS and RACONS do.
Transceivers both transmit and receive without the two functions being directly linked. e.g. your VHF set - and an AIS Class B.
Unfortunately it all got off on the wrong foot several years ago and now nobody would buy a set which was NOT called a transponder.
So now AIS sets are universally known as transponders - so you were right (and, at the same time, wrong!)
AIS CAN be an extremely helpful tool.
But, as Main Sail's Sept., 2010 post (which expressed disappointment with his AIS experience on his Garmin chartplotter) points out, at least two additional factors are important to it's usefulness for any particular boater ...
1- unless you boat in an area where there is significant commercial shipping traffic, AIS isn't going to be of much use to you, ... and
2- YOUR experience with AIS will depend to a great extent on the type of chart plotter and software that you have displaying the AIS information.
Laptop (and desktop) displays are relative large, and the (more recent) Nav software used in them is (usually) better suited to displaying AIS information than small chart plotters.
The larger displays and better nav software provide a much better AIS experience....
Unless, of course, you want to spent thousands of dollars on a newer Raymarine setup with a large display
But, as Main Sail's Sept., 2010 post (which expressed disappointment with his AIS experience on his Garmin chartplotter) points out, at least two additional factors are important to it's usefulness for any particular boater ...
1- unless you boat in an area where there is significant commercial shipping traffic, AIS isn't going to be of much use to you, ... and
2- YOUR experience with AIS will depend to a great extent on the type of chart plotter and software that you have displaying the AIS information.
Laptop (and desktop) displays are relative large, and the (more recent) Nav software used in them is (usually) better suited to displaying AIS information than small chart plotters.
The larger displays and better nav software provide a much better AIS experience....
Unless, of course, you want to spent thousands of dollars on a newer Raymarine setup with a large display
Good explanation Donalex. Did not seem like you were getting on me. Just wanted clarification.
Someday I hope you will see my "transponder/transceiver" sail by your loft.
Is AIS useful?
I'm curious, I understand Tim R. (England) and you folks in San Fran and Maine have shipping traffic to watch out for. Do you really sail out in the shipping lane that much?
We have traffic in the Chesapeake Bay but since it is almost a river we pretty much know where the traffic is and just cross at right angles. I think I've had to "avoid" traffic once in 5 years. We do get barge traffic "out of channel" on occasion though. I've found doing the "changing bearing" drill to be sufficient to tell if I'll pass ahead of or behind.
I'm curious, I understand Tim R. (England) and you folks in San Fran and Maine have shipping traffic to watch out for. Do you really sail out in the shipping lane that much?
We have traffic in the Chesapeake Bay but since it is almost a river we pretty much know where the traffic is and just cross at right angles. I think I've had to "avoid" traffic once in 5 years. We do get barge traffic "out of channel" on occasion though. I've found doing the "changing bearing" drill to be sufficient to tell if I'll pass ahead of or behind.
In The Bay there is a very good VTS, Channel 14, so AIS isn't necessary. That said, I recently sailed in pea soup down on the deck fog and with less than 1/4 mile visibility. It opened up to 1/2 mile as I crossed a shipping channel and a high speed ferry was kind enough to see my radar reflector and slow to assure their safe crossing in front of me. AIS would have been helpful, 'cuz the ferry published schedule doesn't report when they'll be in certain points along their routes.
There is also VTS (ch 12) outside the Golden Gate and they provide reports every half hour
15 & :45). It's outside the Gate that is of interest to me, 'cuz if you look at the charts of the shipping channels outside the Gate, there are three: south, west and north, with the pilot station only 11 miles out.Traveling up and down the coast, you're either stuck between the shipping channel and the shoreline, in some cases not very wide, or you're outside the channel and would need to cross it.
Lotsa stuff can happen in a half hour between the VTS radio VHF reports, and if my software can handle AIS, it would be good to have. I intend to keep the laptop down below and have no issues going down to check. As someone said, if you're absolutely going to need it behind the wheel, you're probably going faster than a sailboat can!
And since AIS computes the CA, and time, you should know what to do way ahead of time.
Here in Maine anything to help see through the fog is a plus. And yes, we are doing more and more overnight races where we cross channels at night. Although AIS is no substitue for radar.
To sail from Portland to Penobscot Bay you could potentially cross 3 major shipping lanes. Casco Bay(tankers), Kennebec River(navy ships) and Penn Bay(tankers).
A little more shipping info about Portland:
In 2008, 766 vessels called at the Port of Portland carrying a total of 14.1 million tons of cargo, including 245.5 TEUs of containerized cargo. Cargoes included minerals (5.5 million tons), grains (4.4 million tons), breakbulk cargoes (977.2 thousand tons), and automobiles (245.5 thousand tons).
And this does not include the 75+/- cruise ships we get per year. And up to 2009 we had a high speed cat ferry.
To sail from Portland to Penobscot Bay you could potentially cross 3 major shipping lanes. Casco Bay(tankers), Kennebec River(navy ships) and Penn Bay(tankers).
A little more shipping info about Portland:
In 2008, 766 vessels called at the Port of Portland carrying a total of 14.1 million tons of cargo, including 245.5 TEUs of containerized cargo. Cargoes included minerals (5.5 million tons), grains (4.4 million tons), breakbulk cargoes (977.2 thousand tons), and automobiles (245.5 thousand tons).
And this does not include the 75+/- cruise ships we get per year. And up to 2009 we had a high speed cat ferry.
My setup
Hi Stu,
Since you mentioned me, I figured I would provide a little more detail.
As I wrote before, I have the Standard Horizon Matrix radio with integrated AIS receiver. I have the RAM (remote) mic at the helm, and it will display AIS information on the small screen. If I am sailing at night, or visibility is poor, I will turn on the CPA alarm. If the alarm goes off, and I can't see the ship that caused it, I will use the remote mic to determine what is going on.
If I'm out for a casual day sail, or simple trip in good weather, the alarms will be off.
On longer trips I have a basic windows laptop at the nav station. It also gets the AIS information from the radio (delivered via an RS232 to USB converter). I use SeaClear, a free chart plotter program, on the laptop, and GPS data comes from a usb puck that works fine down below. Seaclear is much better at displaying AIS info. I can just click on a target to display lots of information (name, status, COG, SOG, destination, MMSI #, etc.).
A few interesting things I have observed from the Matrix AIS / Laptop combo:
-sometimes ships name and other information is displayed on the Matrix screen, and sometimes just the mmsi number is displayed.
-The laptop almost always displayed the ship name and other data
-I have tried to hail 5-10 ships displayed on the AIS screen, none have responded to my request. I used the DSC individual call function, not hailing by name on CH 16.
-One large 'ship' that did not show up on my display was a US Navy submarine. We were returning from Block Island to my home port and we heard the sub broadcast a securite message stating that he would be transiting the race in 15 minutes, and that all vessels must maintain an exclusion zone (or something like that). I watched the sub move by about 2nm behind me - nothing on the AIS display.
-My home port is on the Long Island Sound, close to Port Jefferson, NY. There are ferries between PJ and Bridgeport CT that run all the time. During the day it's easy to see them and determine heading, etc. At night, it's easier to spot them (lots of lights) but not so easy to determine distance and course. The AIS *COULD* come handy then, but I haven't needed it yet.
Barry
Hi Stu,
Since you mentioned me, I figured I would provide a little more detail.
As I wrote before, I have the Standard Horizon Matrix radio with integrated AIS receiver. I have the RAM (remote) mic at the helm, and it will display AIS information on the small screen. If I am sailing at night, or visibility is poor, I will turn on the CPA alarm. If the alarm goes off, and I can't see the ship that caused it, I will use the remote mic to determine what is going on.
If I'm out for a casual day sail, or simple trip in good weather, the alarms will be off.
On longer trips I have a basic windows laptop at the nav station. It also gets the AIS information from the radio (delivered via an RS232 to USB converter). I use SeaClear, a free chart plotter program, on the laptop, and GPS data comes from a usb puck that works fine down below. Seaclear is much better at displaying AIS info. I can just click on a target to display lots of information (name, status, COG, SOG, destination, MMSI #, etc.).
A few interesting things I have observed from the Matrix AIS / Laptop combo:
-sometimes ships name and other information is displayed on the Matrix screen, and sometimes just the mmsi number is displayed.
-The laptop almost always displayed the ship name and other data
-I have tried to hail 5-10 ships displayed on the AIS screen, none have responded to my request. I used the DSC individual call function, not hailing by name on CH 16.
-One large 'ship' that did not show up on my display was a US Navy submarine. We were returning from Block Island to my home port and we heard the sub broadcast a securite message stating that he would be transiting the race in 15 minutes, and that all vessels must maintain an exclusion zone (or something like that). I watched the sub move by about 2nm behind me - nothing on the AIS display.
-My home port is on the Long Island Sound, close to Port Jefferson, NY. There are ferries between PJ and Bridgeport CT that run all the time. During the day it's easy to see them and determine heading, etc. At night, it's easier to spot them (lots of lights) but not so easy to determine distance and course. The AIS *COULD* come handy then, but I haven't needed it yet.
Barry
Is AIS useful?
Bill & Stu,
IMHO, AIS is more than that....
Not only is commercial ( and now, more and more, pleasure boat ) traffic displayed on your chart plotter at a glance, telling you what's out there, it's course and speed, etc. ;
but it also gives you (among other info) the vessels name so that you can call them BY NAME, ... ie, Tug, "Whatever" .. to discuss intentions ... and ( in my experience) they return your call ! !
When displayed on a large(r) screen, (to it's best advantage), in areas with commercial traffic ... and ESPECIALLY, AT NIGHT, ... AIS is, IMHO, far more helpful (and easier to use) than radar.
My AIS is always on and displaying on my chart plotter screen. I rarely turn on my radar... (and when i do, it's usually at night).
For example ... last Summer, I was crossing the Bay, from Mobjack to Cape Charles (West to East). There was a strong ebb tide.
As I approached the center of the Bay, a tug pulling a barge was heading South on a near collision course. AIS gave me a half hour to study both of our positions, speeds, closing rates, CPA, TOCA, etc, (much more easily than I could have done with radar). By adjusting my speed, (and watching the results thereof) displayed by AIS, I could confidently call the tug (by name) and inform him of my intention to cross his bow, and that I could do so at a safe distance. Without the info and knowledge that AIS gave me, I would have had to (unnecessarily) slow way down, wait for the tug and his tow to pass ahead of me, and unnecessarily delay my passage.
Also, ... in the Bay and offshore, especially at night, AIS displayed contacts on my chart plotter make cruising, in general, and collision avoidance, in particular, much easier, and the entire experience more pleasurable... for me, at least.
Bill & Stu,
IMHO, AIS is more than that....
Not only is commercial ( and now, more and more, pleasure boat
) traffic displayed on your chart plotter at a glance, telling you what's out there, it's course and speed, etc. ;but it also gives you (among other info) the vessels name so that you can call them BY NAME, ... ie, Tug, "Whatever" .. to discuss intentions ... and ( in my experience) they return your call ! !
When displayed on a large(r) screen, (to it's best advantage), in areas with commercial traffic ... and ESPECIALLY, AT NIGHT, ... AIS is, IMHO, far more helpful (and easier to use) than radar.
My AIS is always on and displaying on my chart plotter screen. I rarely turn on my radar... (and when i do, it's usually at night).
For example ... last Summer, I was crossing the Bay, from Mobjack to Cape Charles (West to East). There was a strong ebb tide.
As I approached the center of the Bay, a tug pulling a barge was heading South on a near collision course. AIS gave me a half hour to study both of our positions, speeds, closing rates, CPA, TOCA, etc, (much more easily than I could have done with radar). By adjusting my speed, (and watching the results thereof) displayed by AIS, I could confidently call the tug (by name) and inform him of my intention to cross his bow, and that I could do so at a safe distance. Without the info and knowledge that AIS gave me, I would have had to (unnecessarily) slow way down, wait for the tug and his tow to pass ahead of me, and unnecessarily delay my passage.
Also, ... in the Bay and offshore, especially at night, AIS displayed contacts on my chart plotter make cruising, in general, and collision avoidance, in particular, much easier, and the entire experience more pleasurable... for me, at least.
I use both SeaClear and Open CPN. I like the AIS information on Open CPN a bit better, but both are fine. I may move to a purchased program, but looking at the features compared to the free ones, it's hard to justify the expense.
- Status