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post #11 of 16 Old 05-06-2012
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Re: AIS-B questions

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... but the gain in range by having the antenna at the top of the mast vs. 8'+- off the water is considerable.
Not so much. You'll be surprised.

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post #12 of 16 Old 05-07-2012
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Re: AIS-B questions

And, how much range do you need for AIS? 8 or 9 miles is not enough to avoid a massive ship?
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post #13 of 16 Old 05-07-2012 Thread Starter
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Re: AIS-B questions

I don't know how much range is needed, but generally more is better, no? A ship traveling at 22 knots at 8 NM range will give you about 20+- minutes until impact. But perhaps more importantly if you show up on their AIS when they are 20+ NM away there is a better chance that someone on the bridge will notice you sometime during that hour.

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post #14 of 16 Old 05-08-2012
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Re: AIS-B questions

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Originally Posted by jrd22 View Post
I don't know how much range is needed, but generally more is better, no? A ship traveling at 22 knots at 8 NM range will give you about 20+- minutes until impact. But perhaps more importantly if you show up on their AIS when they are 20+ NM away there is a better chance that someone on the bridge will notice you sometime during that hour.
Yes, more is better, BUT... on my last boat I regularly got 20 miles and my record was sixty, and that was a simple antenna mounted on the stern rail. Regardless, 8 would be a MINIMUM I'd expect from any AIS antenna, and yeah, if you have 20 minutes notice and still can't avoid another vessel, AIS is not going to be the thing that saves you from yourself.
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post #15 of 16 Old 05-08-2012 Thread Starter
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Re: AIS-B questions

xy-I was thinking more in terms of single handed and needing the ship to avoid you if you weren't awake to take evasive action. Glad to hear your range was so good from the stern rail, I would rather go that route than use a splitter.

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post #16 of 16 Old 05-08-2012
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Re: AIS-B questions

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xy-I was thinking more in terms of single handed and needing the ship to avoid you if you weren't awake to take evasive action.
This could start one of those nasty ColRegs Rule 5 debates.
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