AIS questions

Alan Gomes

Sustaining Member
Threading through there in morning fog I'm pretty glad they're blasting their AIS signal. Really helps since I don't have radar.
Just curious: Is radar something you would like to add at some point, or is it that you have found AIS by itself adequate for your needs?
 

p.gazibara

Member III
We have had similar annoyances, especially when anchored near large catamarans, they sail back and forth at anchor and are constantly setting off our alarm (on OpenCPN). I eventually just told the thing not to alarm me unless the vessel was moving faster than 2.5 kts. The good news is that they are still displayed, so we have plenty of time to adjust our course when keeping normal watch.

AIS really is a game changer, as you approach, it gives you the other vessels name and call sign, so a quick radio call and they know to look out for you. I don’t know how we sailed in the fog in the PNW without it.
 

Christian Williams

E381 - Los Angeles
Moderator
Blogs Author
Re Radar, we have very little fog here (Marine Layer, spotty, seldom socked in), and no rocks to hit. Never felt the need, although every other boat at the dock seems to have it.

In Maine, yes. But my dedicated Vesper Watchmate serves very well in this stress-free environment.
 

debonAir

Member III
When you're clear of land AIS Rx is probably all you need, and a lot less power-consuming than radar, but in Maine, sailing close to shore in fog (which can come in fast at any time) radar sure helps to find navigation marks and other obstructions, and makes it possible to feel safe to go out on days you'd normally be socked in. I consider it a safety item that can save both your hide and your weekend.
 

Alan Gomes

Sustaining Member
I've had to turn off the AIS alarms on my chartplotter. With the result that I get an alarm saying that the alarms are off. :rolleyes:
Is your plotter a Garmin? I'm guessing maybe not, based on something else you said in that post. But if it is, you might be interested to know that a relatively recent release of their software (for a number of their plotters) added an "Always Off" option for the alarms. Otherwise, turning off the alarms would only hold until the next time you turned on the unit. I just flashed mine with the latest software and it works!
 

debonAir

Member III
Speaking of spurious alarms, I was working on electronics yesterday on the hard, and got a few beeps from AIS. Seems some of my yard neighbors have kept their transponders on over the Winter. I sure hope all the velocities remain 0 for the time being!ais.png
 

debonAir

Member III
Ha :) No I have no room to maneuver! There's a large steel building to my stbd and two boats to port before the seawall and water. On the other hand there's a water spigot and a wall plug just feet away, a flat level lot and a clean bathroom.. hard to want to leave this place. My first time in this yard, Safe Harbor Sakonett in RI, and so far super pleased with it.
 

Alan Gomes

Sustaining Member
I got down to the boat yesterday and wired my GX2200 into my Garmin 546S. It was very simple to do.
I just wanted to add this comment to my own post as a kind of addendum.

Although wiring the GX2200 to the Garmin 546S was indeed trivial, unfortunately I did so based on instructions I found on a website that contained an error. The mistake was subtle enough so that it was not immediately obvious. The AIS targets showed up just fine and the radio worked. I shut everything down and called it good. But later I began to notice some noise on the VHF that seemed unusual. It turns out that there was a wiring error in those particular instructions that led to this problem.

For anyone interested in connecting your GX2200 to a Garmin GPS, please see my detailed post on SBO about this. The wiring I discuss there definitely applies to the GPS546 and to most if not all Garmins of that vintage. For all I know it may apply to current models as well, but you would need to confirm that for yourself.
 
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Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Alan, when the bomb squad cannot determine whether to cut the red or the green wire first, I bet they call you!
(I can sometimes empathize w/the the guy that had trouble pouring water out of a boot when the instructions were written on the heel...)
:rolleyes:
 

Alan Gomes

Sustaining Member
Alan, when the bomb squad cannot determine whether to cut the red or the green wire first, I bet they call you!
(I can sometimes empathize w/the the guy that had trouble pouring water out of a boot when the instructions were written on the heel...)
:rolleyes:
Why thank you, Loren! No calls from the bomb squad yet--though I myself have been tempted to blow up a fair number of electronic gadgets that didn't play nice.

So I'm not the only one, then, who found the wording of that note in the SH manual something less than perspicuous? I interpreted it as best I could with the wiring diagrams in front of me and got lucky, I think. Yaesu tech support confirmed that I was right, but I'm not sure whether that was because when they read it the wording made perfect sense to them right off the bat, or just because they tried what I suggested (based on my interpretation of the note) and found out that it in fact worked. Probably the former since they actually know what they are doing and are used to interpreting stuff like that. Anyway, these are the sorts of problems that can drive a person batty because the wiring in the article *seemed* very plausible on the face of it and worked after a fashion.

I'll be very happy if I can save some poor soul the trouble of sending in his or her perfectly fine radio for repair!
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
An AIS report of a collision in a very crowded area.

Probably the local ship traffic is not this crowded at the mouth of the Columbia River or in the Straits, but the conclusions of the investigation are a bit concerning.
 
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toddster

Curator of Broken Parts
Blogs Author
I just wanted to add this comment to my own post as a kind of addendum.

Although wiring the GX2200 to the Garmin 546S was indeed trivial, unfortunately I did so based on instructions I found on a website that contained an error. The mistake was subtle enough so that it was not immediately obvious. The AIS targets showed up just fine and the radio worked. I shut everything down and called it good. But later I began to notice some noise on the VHF that seemed unusual. It turns out that there was a wiring error in those particular instructions that led to this problem.

For anyone interested in connecting your GX2200 to a Garmin GPS, please see my detailed post on SBO about this. The wiring I discuss there definitely applies to the GPS546 and to most if not all Garmins of that vintage. For all I know it may apply to current models as well, but you would need to confirm that for yourself.
Another wrinkle that arises for some people - I'm not sure about the GX2200, but at some point, Standard Horizon changed the com port in the GX2000, resulting in different wiring instructions for different serial number ranges. You have to follow the specific manual that came with your radio, not necessarily some manual that you find on line. And along the same lines, the older RAM mics are not compatible with newer radios, even though they look the same and have the same "names." (There are slightly different model numbers printed on the data tags.) No problem if you buy both pieces at the same time, but causes problems for "upgrades."
 

Christian Williams

E381 - Los Angeles
Moderator
Blogs Author
I read through the interesting report and concluded that the circumstances illustrate the challenge of a bunch of big ships in fog and a 2-knot current trying to pick up pilots. Yikes.

They cite a CPA of .4 or .3 as acceptable for maneuvering. All I know is that a CPA (Closest Point of Approach) of two miles offshore sets off my collision alarm, and when a containership passes at night at 1 mile away it feels like collision is certain and the engine throbbing noise stands your hair on end.

The subject ships had full radar but it would seem they rely on AIS equally or maybe moreso. Perhaps the AIS data requires less interpretation. The CPAs cited are amazing to me given the lack of maneuverability of large vessels--no sailboat would pass that close, and we can turn on a dime.

Further interest: Apparently Colregs advise against bridges using VHF radio to communicate and to work out close passing situations. If a collision is possible, the idea apparently is to avoid the collision instead of chatting with the other captain about what to do (Because it wastes avoidance time) That's familiar from airplane pilot training, where in case of emergency the radio is low on the list. Fly the plane or steer the ship first.

No indictment of AIS that I could see, although of course I don;t know anything. I do feel reminded to use AIS as one of many tools, the foremost being giving bigger vessels a plenty wide berth.

The whole situation off Algeciras can be easily be replicated in a training simulator-- where collision would have been less violent and career-ending.
 

Alan Gomes

Sustaining Member
An AIS report of a collision in a very crowded area.

Probably the local ship traffic is not this crowded at the mouth of the Columbia River or in the Straits, but the conclusions of the investigation are a bit concerning.
Thank you for sharing this with us, Loren.
 
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