AIS Do I Need It?

[conachair]

Originally Posted by FamilyVan

Not to mention frequently 30 second refresh rates. At 20 knots, 30 seconds represents about 1000 ft. Not exactly a precision instrument.

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The refresh rate at 20kts is actually every 6 seconds or every 2 seconds if changing course. Not that that means it would be clever to try and get within a few inches of a ship or close your eyes.

[conachair]

Originally Posted by El Pinguino

Very cool indeed.... does it also show the length of a tug's unlit tow? [emoji2]

Nope. As you know. But it is very handy knowing it's a tow before you can even see it. Same with survey vessels.


If someone has bothered to update the static data....

[FamilyVan]

Originally Posted by conachair

The refresh rate at 20kts is actually every 6 seconds or every 2 seconds if changing course. Not that that means it would be clever to try and get within a few inches of a ship or close your eyes.

My understanding that was only for newer class A models. B s (at least used to be) slower. I think really old units could have the interval set manually. Any way, even if I'm mistaken about the older units, it still isn't realtime feedback.

Sent from my XP7700 using Cruisers Sailing Forum mobile app

[conachair]

Originally Posted by FamilyVan

My understanding that was only for newer class A models. B s (at least used to be) slower. I think really old units could have the interval set manually. Any way, even if I'm mistaken about the older units, it still isn't realtime feedback.

Sent from my XP7700 using Cruisers Sailing Forum mobile app

To be honest I hadn't even considered a class b doing 20kts. They're far to erratic to assume their course remain the same for any length of time. Still handy knowing one is heading your way though. Big ship class a is easily close enough to real time to accurately see how small adjustments in speed and course will effect cpa from a long way off. And see ships changing course to miss you. Try crossing the English channel a few times with a set and you would fight anyone who tried to turn it off

[El Pinguino]

Sitting in Gulf Harbour just now..... stern mounted AIS Ant ( base of which is 1.7 metres above sea...not on a 'roll bar')..... happily picking up Class B signals from harbour ferries down at Bucklands Beach 16.1 miles away. This isn't 'line of sight' as Rangitoto Island -which is no small thing -lies between here and there. Ant height on the ferries is maybe 6 or 7 metres.

Thats them down lower right.....

The ferries here all run Class B and typically poke along at 20 knots..... HMNZS Wellington is also running Class B... don't know about the rest of the NZ navy.

and also... that's the display software that came with my AMEC.

[boatman61]

About as much as one needs a defibulator..