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Re: AIS
Posted: Thu Oct 08, 2009 11:11 am
by So_Sage_of_Lorne
Nick wrote:.
Now it seems I am arguing against another bunch of fools who seem to want to navigate by AIS at all times. They don't seem to understand that making a course alteration based on a CPA calculated by AIS from a ship twelve miles away is a mug's game. The CPA is based on data available at that time and predicted into the future. However, it is run by computer, not a crystal ball. There is no guarantee that the ship in question is not about to make a course alteration, and of course there is no guarantee that you in a saily boat will be able to maintain your course and speed - thus CPAs calculated from this sort of distance are at best approximations.
I personally use the AIS as an aid to monitor any so equipped vessel which appear to be on a converging course. The CPA information has been valuable to me on several occasions usually when I have been able to predict the other vessels intentions and opened up the CPA by altering course earlier than I would have done using a HB compass.
I have also used VHF to great effect when caught out in a dense fog bank mid channel without radar. An all ships call was answered by a freighter 18nm away coming down channel, he identified us on his radar and then proceeded to give us information and up dates on all potential threats all the time he was within VHF range.
Re: AIS
Posted: Thu Oct 08, 2009 11:32 am
by Nick
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I too would monitor the AIS readout if I had it available, and while I can rarely see myself make course corrections based on a CPA calculated from over ten miles away I am not suggesting that this may NEVER be appropriate, just that I don't think it should be SOP.
But then you my old sausage are a sensible and non-dogmatic person with or under whom I would be happy to sail. Using all the tools at ones disposal in the most appropriate manner for the situation is the name of the skippering game is it not?
OTOH, claiming to be an all-knowing guru of the new way is not the sort of behaviour I would relish in a skipper.
Re: AIS
Posted: Thu Oct 08, 2009 11:36 am
by claymore
Fer Jay's sake - be honest. You are just trying to cadge a lift on a decent boat.
Re: AIS
Posted: Thu Oct 08, 2009 12:16 pm
by Nick
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Fer Jay's sake - be honest. You are just trying to cadge a lift on a decent boat.

Sussed!
Re: AIS
Posted: Thu Oct 08, 2009 12:19 pm
by Alcyone
This really is very exciting. An argument on two boards.
It's my first trans dimensional cyber war.
Re: AIS
Posted: Thu Oct 08, 2009 2:14 pm
by sahona
I can't resist it...
Until AIS is cheap and installed on everything I'm likely to impact on a voyage, it's of no real use to me - in fact, when it gets to the stage where "nearly everything" shows up, it's going to be accepted (like a plotter is now), and really dangerous when you meet the guy that hasn't yet subscribed.
However, i'm happy that it's another "not in my lifetime" thing like DSC has turned out to be for some.
Next cash I get my grubbies on is going on a Radar upgrade/modernisation.
Re: AIS
Posted: Thu Oct 08, 2009 3:20 pm
by So_Sage_of_Lorne
Nick wrote:.
But then you my old sausage are a sensible and non-dogmatic person.
Thanks for that, however I expect Desperate Dan will be along in a minute to shatter the illusion.
OTOH, claiming to be an all-knowing guru of the new way is not the sort of behaviour I would relish in a skipper.
Dangerous even in command of a keyboard!
Re: AIS
Posted: Thu Oct 08, 2009 3:22 pm
by So_Sage_of_Lorne
Nick wrote:.
Fer Jay's sake - be honest. You are just trying to cadge a lift on a decent boat.

Sussed!
There is a possibility that an invitation may have been proffered elsewhere.
