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Old 30-08-2015, 00:55   #16
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Re: AIS benefits

We receive AIS, but prefer to monitor our own radar and use our eyes. It's foolish to believe others are always watching out for you via your AIS broadcast or monitoring their own radar. AIS alone does not solve the problem.

Keep a good lookout, watch out for others, don't expect the other guy to be watching out for you.
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Old 30-08-2015, 01:23   #17
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Re: AIS benefits

Quote:
Originally Posted by Kenomac View Post
We receive AIS, but prefer to monitor our own radar and use our eyes. It's foolish to believe others are always watching out for you via your AIS broadcast or monitoring their own radar. AIS alone does not solve the problem.

Keep a good lookout, watch out for others, don't expect the other guy to be watching out for you.
I honestly don't think ANYONE would question that wise advice Kenomac. In all the AIS threads I've never read of someone suggesting there is no need to keep a good look out or to rely on someone else watching you.

BUT, being seen is at least in Australia a requirement if your off sure. It is a requirement to have a radar deflector of some sorts. This would indicate that making yourself visible is a good and wise part of exercising good seamanship.
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Old 30-08-2015, 01:49   #18
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Re: AIS benefits

Rustic,

You'd be surprised by the boneheads out there, I know of several couples who recently equipped their new boats with only AIS and decided to go without radar on their worldwide cruise aboard their expensive yachts. In their minds, radar was outdated tech and AIS was new and "easier to use."

I even had an idiot on my boat last season for a short time, who's idea of the proper way to sail was to set the bearing on the chartplotter to the destination, leave it on auto pilot, then go below, drink a bottle of scotch and take a nap. He thought I was a "f&@$ing idiot" because I insisted on keeping a constant watch and monitoring course.... Needless to say, he won't be invited back.
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Old 30-08-2015, 03:04   #19
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Re: AIS benefits

Quote:
Originally Posted by Kenomac View Post
Rustic,

You'd be surprised by the boneheads out there, I know of several couples who recently equipped their new boats with only AIS and decided to go without radar on their worldwide cruise aboard their expensive yachts. In their minds, radar was outdated tech and AIS was new and "easier to use."

I even had an idiot on my boat last season for a short time, who's idea of the proper way to sail was to set the bearing on the chartplotter to the destination, leave it on auto pilot, then go below, drink a bottle of scotch and take a nap. He thought I was a "f&@$ing idiot" because I insisted on keeping a constant watch and monitoring course.... Needless to say, he won't be invited back.
in that case I take it back. There truly are foolish people out there.

I have had one local comment from someone criticising the need for radar. But that was coming from someone who has never been out of our river. So I didn't take a lot of notice of him.
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Old 30-08-2015, 05:49   #20
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Re: AIS benefits

After 6 days of navigating in fog, often 1/10 of a NM visibility or less, I have a couple of observations. One is that AIS is great. Knowing the name and type of vessel, CPA and all the rest, is helpful. More than once I was hailed by, or hailed, another vessel by name to make arrangements.

Downside: It used to be you'd just monitor, or turn to avoid, all those "blips" on radar, passing without ever seeing or speaking to each other. Now, if you both have AIS, one of you is likely to feel the obligation to call the other and make passing arrangements. It is reassuring when it happens once or twice. It can get tedious after a while. Yes, I know you're there. Yes, my two radars and my AIS are all telling me we're going to pass port to port with plenty of room to spare. You have a nice day too.
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Old 30-08-2015, 07:23   #21
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Re: AIS benefits

The bottom line is all about "situational awareness" and as most would agree having AIS in is great but having AIS out is best. See and avoid is the hallmark of aviation and we use the new ADS-B system which is AIS like and in 2020 will be mandated for all aircraft operating in what I'll label controlled airspace.

The big difference for aviators is that we have air traffic controllers who will call out traffic and vector me away from faster/heavier traffic.

Information is key in terms of safety and AIS class B is just one of the components. Given all the other costly additions in the marine electronics world the cost of a class b unit is not the huge obstical facing the vast majority of aging aircraft in the U.S. Where the cost of ADS-B at present will be as much as a third the value of said aircraft.
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Old 30-08-2015, 08:37   #22
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Re: AIS benefits

Quote:
Originally Posted by Kenomac View Post
We receive AIS, but prefer to monitor our own radar and use our eyes. It's foolish to believe others are always watching out for you via your AIS broadcast or monitoring their own radar. AIS alone does not solve the problem.

Keep a good lookout, watch out for others, don't expect the other guy to be watching out for you.


Collision avoidance is my responsibility. Just like on the motorcycle, my operating assumption is that drivers (be they cars or boats) don't see me. It's great when they do, but I have no way of knowing what they know. All I can control is me, and so I do.
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Old 30-08-2015, 09:13   #23
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Re: AIS benefits

AIS is one of the most useful tools that has come about for the marine industry. There are limitations, of course. I highly encourage all small vessel owners (within their monetary means) to get class B as sometimes it is difficult to get a good target on radar. I use the AIS data as a guide to judge a meeting situation, but will fine-tune the radar once I know a vessel is out there. CPA data is way off at distances greater than a few miles. You'll often see in a radar overlap the AIS icon is riding along beside the radar target. I used to think it was a pain when everyone had his AIS "on" when not underway. However, with most ECS/ECDIS nowadays, the AIS icon of a vessel that is underway with show the true vector coming off of it. Even in busy ports, a watch stander that is paying attention should have no issue discerning this.
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Old 30-08-2015, 11:22   #24
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Re: AIS benefits

James,
I don't wish to dampen your enthusiasm, nor wish to write a treatise on AIS...
And, I certainly am not wading into another AIS vs. Radar argument...sort 'a like the "SSB vs. Satphone" arguments from last couple years!

But, I do wish to clarify a few things for you (and others), that are rather important to understand...


Regardless of your experiences and opinions, you have a few facts incorrect...
Quote:
Originally Posted by Banshe View Post
AIS would have to be one of the biggest breakthroughs for marine safety since the invention of radar seventy odd years ago. Land stations have popped up like mushrooms all over the world giving amazing coverage. Sometimes up to one hundred miles off shore. Signals are also relayed on from ship to ship so as long as they are within fifty odd miles of each-other. I have been able to see ships over four hundred miles at times in busy shipping lanes. And it's only going to get better.
1) While in some areas there are land-based AIS "repeaters" (assuming this is what you are referring to as "land stations"), which retransmit AIS transmissions....these are not as widespread as you think....and of course, are limited by the range they can see/transmit...
(and in actuality, in most areas are only used to get AIS signals around obstructions such as hills, bluffs, etc.)


2) AIS transponders (whether Class A or Class B) do NOT relay AIS information from ship-to-ship-to-ship!!
The AIS system is designed that a ship transmits it data to all other ships in range and all those other ships withing range also transmit their data...

As an example, say there are 3 ships about 50 miles behind each other:

-- Ship A's data goes out, and ship B is within range and sees ship A's data (and vice versa), but ship C is too far away to get ship A's signal (and vice versa)

-- Ship C's data goes out, and ship B is within range and sees ship C's data (and vice versa), but ship A is too far away to get ship C's signal (and vice versa)

-- Ship B, in the middle between A and C, gets both A and C's data, and both A and C get ship B's data....

-- BUT...
But, ship B's AIS transponder does NOT relay the other ship's data to anyone else!!


3) The reason you have occasionally seen AIS data from vessels "over four hundred miles at times", is due to enhanced VHF radiowave propagation...
(or perhaps you have been in one of the few areas with a land-based AIS repeater network, with high antennas, etc...but, even then, their range is also limited to significantly less than a couple hundred miles unless there is a linked-network of multiple land stations)

For a good explanation of VHF radio and AIS radiowave propagation and range, please see this thread here...
VHF and AIS Radiowave Propagation and VHF and AIS Radio Range






4) If my basic info isn't enough, please have a look here..where you'll find lots of info on the AIS system..


http://www.navcen.uscg.gov/?pageName=aismain
http://www.navcen.uscg.gov/?pageName=AISFAQ







I do hope this helps clarify things for you.

Fair winds..

John



P.S. I wasn't going to voice any opinion here....but, just couldn't help myself...
I have had AIS receiver on-board since 2006, and a Class B AIS transponder since early 2012, and have also sailed > 15,000 miles offshore with them...
And, while I DO like the AIS system as a whole (as well as the Vesper Watchmate's), I'm quite loath to say that anyone without AIS is "foolishness and is placing unnecessary danger to themselves and an unfair burden on the Masters of large ships"...
Seriously??
I've been sailing/cruising on and off for about 50 years now (started as a kid, in the 1960's), and have made my living in the electronics industry for > 30 years....
My first Atlantic crossing was 35 some years ago...well before even GPS! (and, my most recent couple were just a few years ago..)
And, we did what every mariner is still supposed to do, navigate and keep watch in a seamanship-like manner! Goodness, how reckless we were back-in-the-day, placing
our lives at risk...and asking other vessel's crew to actually do the same?
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Old 30-08-2015, 14:22   #25
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Re: AIS benefits

Thank you for your reply and opinions. It is always good to hear the negative. I still maintain that AIS is the the future to avoid collision at sea.

PS. It should be noted that you attacked me personally. Not through the channels provided through free speech.

James
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Old 30-08-2015, 14:28   #26
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Re: AIS benefits

Quote:
Originally Posted by Mike OReilly View Post
I suppose that's a good reason to transmit. Luckily our Canadian water cops seem less enamoured with randomly stopping boats without cause. In all my years of boating on the GL I've been "safety inspected" once.

I did have a close encounter with our MIB (RCMP and border service in a joint scary boat), but it turns out they only came over to inquire about our wind vane. The officer was a fellow sailer and just wanted to know how often we used the Aries. Too funny...


Why go fast, when you can go slow
We really like the comparison. Your boarder guys seem way less stressed. Really pretty nice bunch. Our USCG is mostly great guys too. Its the locals and HS that give us the willies.

Lots of responders keep talking about the vast number of targets; too many spots on the screen etc. The Watchmate 850 has great filtering for removing targets that don't matter. Any proper AIS should do this or it will be a pain in the butt. At anchor, we switch our profile to "Anchored" and use the anchor watch feature. This is only about 8 watts and notifies you if you move outside the set circle. It also places a pin prick on the screen every few minutes, showing a sleepy skipper where you have been all night.
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Old 30-08-2015, 15:48   #27
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Re: AIS benefits

James,
You're quite welcome.

And, while we can all to politely agree to disagree on opinions, I think the facts are always good to know...
(Of course, that's just my opinion... )
I do hope you look at the facts provided?



Now, I've read what I wrote over and over, and I cannot find where I was negative at all, nor "attacked" you at all...and certainly NEVER meant anything personal!
I was simply supplying some facts and clarifications (and added my own experiences in a post script, in a fun, friendly way, with smiley faces and everything! ).

But, like a gentleman, I will nonetheless extend my apologies and say I'm sorry if anything I wrote offended you!


Fair winds...

John
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Old 30-08-2015, 16:54   #28
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Re: AIS benefits

Quote:
Originally Posted by Banshe View Post
Thank you for your reply and opinions. It is always good to hear the negative. I still maintain that AIS is the the future to avoid collision at sea.

PS. It should be noted that you attacked me personally. Not through the channels provided through free speech.

James
Attacked you personally??? I really haven't seen any of that in this discussion. Unless, maybe you only intended it to be a one way, all in agreement type discussion.... Only Cheers allowed for AIS. If that's the case.... I simply have to disagree with your declarative.
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Old 30-08-2015, 17:54   #29
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Re: AIS benefits

Quote:
Originally Posted by Banshe View Post
Thank you for your reply and opinions. It is always good to hear the negative. I still maintain that AIS is the the future to avoid collision at sea.

PS. It should be noted that you attacked me personally. Not through the channels provided through free speech.

James
I'm at a loss to see where you think you were 'attacked', whether personally or not.

Aside from this, I happen to agree with you. AIS is the future to avoid collision at sea. Of course there are others, and AIS will never ever take away the neccesity for 'keeping a look out' , which will always ALWAYS be the number one collision avoidance action. It is still exceptionally beneficial and as I previously stated, at least in Australia there is an expectation and possibly a legal obligation to ensure one can be 'seen'.
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Old 30-08-2015, 18:04   #30
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Re: AIS benefits

Quote:
Originally Posted by ka4wja View Post
James,
I don't wish to dampen your enthusiasm, nor wish to write a treatise on AIS...
And, I certainly am not wading into another AIS vs. Radar argument...sort 'a like the "SSB vs. Satphone" arguments from last couple years!

But, I do wish to clarify a few things for you (and others), that are rather important to understand...


Regardless of your experiences and opinions, you have a few facts incorrect...

1) While in some areas there are land-based AIS "repeaters" (assuming this is what you are referring to as "land stations"), which retransmit AIS transmissions....these are not as widespread as you think....and of course, are limited by the range they can see/transmit...
(and in actuality, in most areas are only used to get AIS signals around obstructions such as hills, bluffs, etc.)


2) AIS transponders (whether Class A or Class B) do NOT relay AIS information from ship-to-ship-to-ship!!
The AIS system is designed that a ship transmits it data to all other ships in range and all those other ships withing range also transmit their data...

As an example, say there are 3 ships about 50 miles behind each other:

-- Ship A's data goes out, and ship B is within range and sees ship A's data (and vice versa), but ship C is too far away to get ship A's signal (and vice versa)

-- Ship C's data goes out, and ship B is within range and sees ship C's data (and vice versa), but ship A is too far away to get ship C's signal (and vice versa)

-- Ship B, in the middle between A and C, gets both A and C's data, and both A and C get ship B's data....

-- BUT...
But, ship B's AIS transponder does NOT relay the other ship's data to anyone else!!


3) The reason you have occasionally seen AIS data from vessels "over four hundred miles at times", is due to enhanced VHF radiowave propagation...
(or perhaps you have been in one of the few areas with a land-based AIS repeater network, with high antennas, etc...but, even then, their range is also limited to significantly less than a couple hundred miles unless there is a linked-network of multiple land stations)

For a good explanation of VHF radio and AIS radiowave propagation and range, please see this thread here...
VHF and AIS Radiowave Propagation and VHF and AIS Radio Range

4) If my basic info isn't enough, please have a look here..where you'll find lots of info on the AIS system..

http://www.navcen.uscg.gov/?pageName=aismain
http://www.navcen.uscg.gov/?pageName=AISFAQ
I do hope this helps clarify things for you.

Fair winds..

John

P.S. I wasn't going to voice any opinion here....but, just couldn't help myself...
I have had AIS receiver on-board since 2006, and a Class B AIS transponder since early 2012, and have also sailed > 15,000 miles offshore with them...
And, while I DO like the AIS system as a whole (as well as the Vesper Watchmate's), I'm quite loath to say that anyone without AIS is "foolishness and is placing unnecessary danger to themselves and an unfair burden on the Masters of large ships"...
Seriously??
I've been sailing/cruising on and off for about 50 years now (started as a kid, in the 1960's), and have made my living in the electronics industry for > 30 years....
My first Atlantic crossing was 35 some years ago...well before even GPS! (and, my most recent couple were just a few years ago..)
And, we did what every mariner is still supposed to do, navigate and keep watch in a seamanship-like manner! Goodness, how reckless we were back-in-the-day, placing
our lives at risk...and asking other vessel's crew to actually do the same?
John, I personally think your being a bit picky (pedantic) with your post. But aside from that, when you place a sentence in speach comma's like you have and italics as you have with this bit I put in bold, it generally means you are quoting someone. Now, I've read this entire thread just to be sure, and I can't see where you have quoted this from? I can't see any post that even resemble's someone suggesting that 'not having AIS is foolish'. Which makes your whole PS quote a bit like your looking to establish a fight of some sort? I hope that was not your intention, but why quote and reply to your own quote that no one else has propositioned?
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