AIS with Internet

[bewitched]

Originally Posted by Lancerbye

You have container ships out there travelling at 25 knots ?

We do. And the high speed ferries (hydrofoils and turbocats) are doing about 35knots on the Hong Kong to Macau run. One every 5 mins or so.

For fun I googled 'average speed of container ship'. The first 3 results were:
Up to 25kts
21 to 25kts
23kts

So yes, 4 or 5 miles every 10 mins or so.

[bewitched]

Originally Posted by AussieGeoff

I'd refresh it at not more than sixty second intervals, so a cargo ship at 14kts will have moved around a 1/4 of a mile. Even allowing another thirty seconds for lag and a redraw, that's still well under a mile it will have moved.

But there are other factors adding to the inaccuracy. Like how often is the website updated? Every 30 seconds? Every minute? Longer? It's an unknown.

How old was the AIS transmission for a particular vessel when it was uploaded. How old is the transmission now? More unknowns.

To many unknowns for me to ever rely on it in any short range situation.