Vessel finder.

vyv_cox

vyv_cox

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I recently installed an AIS transducer, Digital Yacht CLB2000. It receives OK and the LEDs tell me it is transmitting. Yesterday we sailed about 20 miles and I used Vessel Finder to check that we were visible. We were not but other boats within a mile or two were.
This morning I have been looking at VF again and find that many boats around us are not seen, whereas they are on my plotter. Boats that I looked at sailing past hours ago on VF remain in the same position. I cannot see any way of updating the view.
We have good internet here (Alinda on Leros). Can anyone offer any hints please?
 
Although they are pretty good, these AIS sites seem to be a bit hit and miss, one reason not to rely on them on board.
 
Vyv,
I had this issue also with using vessel finder. I suspected my aerial splitter and generally spent some time fault finding and changing aerial cable etc. Eventually I asked a close by boat which I could see on my AIS and also on vessel finder. He could see me on both. Painful as it was I spent £4 on the Marine Traffic IPhone APP and it shows my boat with no issues! Still a bit of a mystery!

I would try the marinetraffic website first on your PC or whatever you use.
Regards
Angus
 
Trying another website is definitely worth trying.

Are you still not visible this morning Vyv? I find that we are quite often not visible because we must be in a blind spot of some kind but once we have been picked up, we seem to stay on screen but it is all very hit and miss.

Richard
 
yotter said:
Vyv,
I had this issue also with using vessel finder. I suspected my aerial splitter and generally spent some time fault finding and changing aerial cable etc. Eventually I asked a close by boat which I could see on my AIS and also on vessel finder. He could see me on both. Painful as it was I spent £4 on the Marine Traffic IPhone APP and it shows my boat with no issues! Still a bit of a mystery!

I would try the marinetraffic website first on your PC or whatever you use.
Regards
Angus
Click to expand...

I also installed Marine Traffic on my Android phone; it shows most of the traffic; better than some other apps but not totally accurate or reliable
 
The AIS websites rely on a network of marinas, ports and interested amateurs (plus satellite receivers which are very unlikely to pick up Class B) who have a receiver and internet connection. As such, their reception can be very variable and subject to local condition changes. Far better to check with other vessels than rely on these sites.
 
Hermit said:
The AIS websites rely on a network of marinas, ports and interested amateurs (plus satellite receivers which are very unlikely to pick up Class B) who have a receiver and internet connection. As such, their reception can be very variable and subject to local condition changes. Far better to check with other vessels than rely on these sites.
Click to expand...

+1. You're basically relying on an amateur network that may or may not be operating correctly in your area of interest. If you search for my boat, Capricious, you will find her at Grimsby - where she has never been, nor has my mobile phone! I don't have a transducer but did use the mobile phone app while moving from the Cyde to East Anglia.
 
I'm not sure if you can on Vesselfinder, but on the marinetraffic website and on their App you can see the 'AIS source', i.e. who is hearing your AIS transmission and forwarding it to the internet.

Perhaps try clicking on a boat near you that is visible in marinetraffic, then clicking on the AIS source button. This will come up with the receiving station antenna location and antenna height. This might clear up whether or not you're in a black spot or just too far away.
 
Vyv
As Martin J says Marine Traffic shows interesting stats for the AIS receiving station.
Looking at the polars for ASVESTAS TEMENIA LEROS the max target acquired distance @45 degrees from the receiver in Laki is 5 miles for class B targets
Id assume that Alinda is on the limit of range ?
 
Vyv are you splitting off your masthead VHF or a dedicated one lower down in the pushpit for example? I obviously don't need to say this to a man of your experience but a deck level transponder will have nothing like he range of a masthead one. Although unlikely to make much difference if detected by sataalite. We often get plotted on Marine traffic as "via satalite" if we're not in range of a land based receiver.

Sometimes Marine traffic is better and sometimes VesselFinder. Right now in El Hierro Canaries we find VesselFinder will plot us where Marine Traffic won't.
 
As others have said, the information for Marine Traffic and others relies on shore stations. I think that I am right that Vessel Finder and Marine Traffic use their own shore stations and that is why one can appear on one and not on the other. In general Marine Traffic seems to have the best coverage

If you want to make sure that you position on MT is accurate you can use their OnCourse app https://help.marinetraffic.com/hc/en-us/articles/205327417-How-can-I-report-my-positions-using-mAIS This takes your position from your phone and ties it into your AIS position and fills the gaps. When we crossed from Italy to Croatia, we were out of range of shore stations for AIS but still have phone signal almost all the way across.

It is quite nice if family or friends are tracking you remotely,

TudorSailor
 
We have a rubber duck type antenna on the stern arch. Clearly not as good as a masthead unit but probably good enough.

However, there is clearly a problem in Alinda, as Steve suggested. None of the vessels in here show on three sites, the cat ferry has been in twice with no show and two yachts that left Lipsi this morning covered a little over a mile in four hours!
 
Quiddle said:
Which, in my experience, is a concept to extend to AIS in general
Click to expand...

Appearing on a website is a luxuary and fun but most importantly you appear on other ships receivers and I've never had reason to believe this isn't the case.

One thing I did find is that my computer monitor disrupted the unit / gps. Something in the frequency of the LED monitor stopped us from picking up enough satalites to get a solid fix. Without the min number of satalites it won't transmit a fix.

When I moved to monitor more than 12 inches from the ais box then it was ok. My box has inegtrated GPS so that may well be the problem whereas many AIS users have a dedicated GPS unit outside.
 
johnalison said:
Yes. I believe that popping out of the cabin and having a peek at the horizon occasionally is, by and large, a good idea.
Click to expand...

Yes, that is just what we do, except the visual is the first indication. In the Aegean there are no shipping lanes, islands are serviced by ships that might be going in any direction. We installed AIS because of this. We were very nearly run down twice by ships whose intentions were impossible to predict. We knew he was there but that did not prevent him from trying to ram us.
 
I have Marine traffic on my Android tablet and phone and have been able to follow my friends boats from West Wales to Scillies, CIs and St Malo. It's fine for casual use but doesn't update as often as ship to ship AIS. Of course you can't use it at see as there's no WiFi.
 
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