AIS -too much clutter already?

[Koeketiene]

My AIS aerial is only on the pushpit whereas if it was higher then a greater range.

Could well be why you dropped off the plot when crossing the Thames estuary on the outside - ours sits 19.6m up the mast (VHF antenna/splitter)

 

[johnalison]

As far as clutter is concerned, our record on this trip has been 100 AIS signals within 1.3 miles of us - that was passing through Amsterdam on the North Sea canal.

We also found the AIS interesting on the Kiel canal. There are lights on the side of the canal warning various categories of large ships to stop, and you can work out what is coming in the other direction that determines that oncoming ships must stop. Then we passed one ship that was bound for the timber yard just a mile from our mooring... Endless interest on an otherwise rather boring canal.

You can see that Johnalison and I are weather bound, from our postings, can't you - he is near Kiel, and I am in Denmark, and the wind and rain are all getting a bit much!

I usually prefer to look where I am going in Amsterdam.

The Kiel canal is actually very pleasant and quite attractive in places, with plenty of bird life, mergansers and pink-footed geese. We had the unusual experience of encountering three red lights, which means all vessels must stop. A lighter with a massive load was manoeuvring, but the lights cleared as we approached. At another site, a large ship had anchored in the middle of the canal and vessels were passing both sides. AliM will know how weird this is.

Weather-bound? Too right today.

 

[AliM]

We had 90 minutes wait for three red lights last year. A very large cruise ship was being towed by several tugs past the windy bit by Rendsburg. We stopped at one of the passing places and tried to moor up to a massive dolphin. I manage to lasso the bollard on the top, but hadn't seen a common gull nesting there, which dive bombed furiously. We quickly moved to another bollard to the amusement of some of the other yachts. We were able to work out what was going on from the AIS. Have you anchored in Flemhuder? A lovely calm lake with excellent birds, just a few hundred metres off the canal about 10 km short of Holtenau.

Weather is easing and looks warmer for the next week, at last.

 

[Gargleblaster]

The discussion on range in the North Sea is interesting, where land based receivers seem to lose signals when they are 15 miles out. My experience of AIS is largely confined to my own reception of signals on various boats I have been on. I was in South Atlantic in 2013 and became so confident that I would receive a signal from at least 50 miles away that I would happily turn off my set while I was asleep and only turn it on every 2 hours or so when I did a normal visual check. I did leave it on for at least 2 minutes to give it time to receive. It was interesting that I would regularly receive AIS information from ships 300 miles away, occasionally from up to 600 miles away and on one occasion from 900 miles away. Without knowing the intricacies of Class A transponders I was wondering if there was a rebroadcast facility built into them as generally when I was receiving from an unusual distance there were intervening ships.
I thought I knew a bit about radio propagation having been involved in a trial for a new HF radio set for the Australian Army in Papua New Guinea on a Long Range Patrol in the Seventies. And find it very unusual that a VHF signal should be anything other than line of sight.
My record for the greatest concentration of ships was entering Cristobal Harbour in Panama [Colon, Caribbean side] with 140 targets on the AIS just after midnight local time, fortunately most of them were at anchor. But one was maneuvering about a cable in front of us and a cable from the breakwater and my indecision as to whether to proceed caused Cristobal Signal Station to tell me to stop faffing around and enter the harbour as the ship that was bothering me was in the process of anchoring.

 

[johnalison]

We had 90 minutes wait for three red lights last year. A very large cruise ship was being towed by several tugs past the windy bit by Rendsburg. We stopped at one of the passing places and tried to moor up to a massive dolphin. I manage to lasso the bollard on the top, but hadn't seen a common gull nesting there, which dive bombed furiously. We quickly moved to another bollard to the amusement of some of the other yachts. We were able to work out what was going on from the AIS. Have you anchored in Flemhuder? A lovely calm lake with excellent birds, just a few hundred metres off the canal about 10 km short of Holtenau.

Weather is easing and looks warmer for the next week, at last.

Yes, we've anchored there a couple of times when doing the whole canal in one hop but now that we are older and wiser,
We do Cuxhaven-Rendsberg and then Rendsberg-Laboe. Lots of birds but too windy for the small ones. Recorded 41kn yesterday.