In praise of AIS

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doug748

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I came back from France recently in poor visability. Never saw a sausage between L'aberwrach and the Eddystone.

The AIS was magnificent, I could have kissed it.

Not sure what the point of this post is except, perhaps, if you are still considering it go for it; particularly if you sail shorthanded.
 
doug748 said:
I came back from France recently in poor visability. Never saw a sausage between L'aberwrach and the Eddystone.

The AIS was magnificent, I could have kissed it.

Not sure what the point of this post is except, perhaps, if you are still considering it go for it; particularly if you sail shorthanded.
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Yes - I recently crossed the channel on a boat equipped with it and even though the visibility was okay it was still very reassuring. I'm going to get one now I think.

Yes it has loads of limitations but all in all a useful tool - IMHO better than radar
 
30boat said:
I would think that AIS complements radar beautifully,it's not an alternative.
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Agree - over the last 10 days we (wife/myself) have used both for 3 days in thick mist and fog up the Irish sea doing legs of 60 miles plus each day. The AIS picked up all shipping and most fishing boats, the radar the remaining fishing boats and yachts. We had several occassions when fishing boats / yachts appeared out of the murk only 100/200m away but we were not surprised and prepared to see. On our second day we "saw" at least 20 fishing boats on AIS within a mile of our course, but only saw 3/4 of them with our eyes! The radar also picked them all up clearly.

Without both it would been a very stressful and exhausting sail, also high risk - we know from previous times when we had neither!
 
More detail required.

doug748 said:
.

The AIS was magnificent, I could have kissed it.

Not sure what the point of this post is except, perhaps, if you are still considering it go for it; particularly if you sail shorthanded.
Click to expand...

In what way was it magnificent? How did it improve your trip? What benefits did it convey over the other navigational aids?:confused:
 
Absoloutely brilliant, the ability to see the details of the boat thats about to run you down is a real bonus.

Not sarcastic, we were heading for Porto and a large cargo boat was outbound on the nose towards us at about 4 miles, CPA and TCPA were showing and it seemed every time I altered to starboard a couple of degrees he did the same to port, eventually with the AIS detail I called him on 16. A reply came back that he had seen me and he then altered course to starboard and I could see the rudder angle applied all courtesy of AIS.

A real benefit to your health in reduced stress levels:)
 
30boat said:
I would think that AIS complements radar beautifully,it's not an alternative.
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You mean you can't have one or the other - you have to have both?

Not my understanding - I have certainly been on a boat with AIS and no Radar and that seemed to work just fine. Perhaps you have an unusual installation.

AIS is not perfect - but it is much less open to misinterpretation than radar.

In fact I think I would prefer to fit an AIS "transponder" (yes, I know they aren't really transponders) before fitting radar - only they are ridiculously expensive.
 
FistralG said:
In what way was it magnificent? How did it improve your trip? What benefits did it convey over the other navigational aids?:confused:
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In my experience it will tell you everything about the nearby traffic, at a glance - name, speed, course, rate of turn, and crucially - closest point of approach, time to CPA, and really importantly the orientation at CPA.

I have never used radar, but to have all this information and more (eg MMSI) instantly is a real stress-reliever.

Read for yourself.
http://www.vespermarine.co.uk/marine-safety-products/ais-watchmate-tx.html/#features

Edit - one huge advantage over radar is that it consumes almost no electricity - even when the transmit feature is switched on.
 
reassured

doug748 said:
I came back from France recently in poor visability. Never saw a sausage between L'aberwrach and the Eddystone.

The AIS was magnificent, I could have kissed it.

Not sure what the point of this post is except, perhaps, if you are still considering it go for it; particularly if you sail shorthanded.
Click to expand...

Just picked up an NasaAIS3 on ebay at a very good price, unused. How have you connected to your arial? I am going to use this on the lapton with OpenCPN, already have a GPS dongle fitted, so hopeful it will work well.
Mike
 
mikemacdonald said:
Just picked up an NasaAIS3 on ebay at a very good price, unused. How have you connected to your arial? I am going to use this on the lapton with OpenCPN, already have a GPS dongle fitted, so hopeful it will work well.
Mike
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Sorry, I can't help with that Mike.

I use a Digital Yacht combined plotter/AIS on deck with a simple telescopic aerial directly connected
 
bedouin said:
Yes - I recently crossed the channel on a boat equipped with it and even though the visibility was okay it was still very reassuring. I'm going to get one now I think.

Yes it has loads of limitations but all in all a useful tool - IMHO better than radar
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We sailed from Plymouth to Falmouth and back during the last week, mostly in appalling conditions, high winds, rain and poor visibility.

I've got both radar and AIS and wouldnt be without either of them now.
What was quite suprising was the number of quite large fishing boats we had to avoid who weren't transmitting AIS data. Without radar we just wouldn't have know they were there.
 
Kiss my AIS!

We crossed from Plymouth to Guernsey and then back to Dartmouth. Both overnight. Return in less than perfect vis. No radar.

I _did_ kiss my AIS (did that sound rude?)

We did not need to change course or speed once, and calmly passed behind and in front of about 5 huge vessels safe in the knowledge that we'd definitely miss them.

The proximity alarm feature was brilliant. And the MMSI no. and vessel name to hand so that if we DID have to chat to them there'd be no "large vessel in approx position xxx yyy... please respond", it would be "SHEILA B COMING, THIS IS SMALL YACHT IN FRONT OF YOU!". Brilliant!

We had the NASA receiver with screen and installed a pushpit mounted antenna, and used a connector adaptor on the back of the AIS which meant it would be a very simply matter to then unplug it and re plug it back in the VHF as a backup.

But you have to wonder if it would breed complacency. Some boats don't have transponders. Some boats might have broken transponders. Only a good watch or radar could detect those.
 
AIS is a brilliant tool, but only as an addition to, and not a substitute for, radar and correct watchkeeping. As an example, a couple of months ago I was on passage between Stornoway and Kinlochbervie, sea conditions and visibility excellent. An AIS target appeared which described itself as a tug (a big one, 150 feet long) and restricted manoeuverability. CPA was about half a mile, with which I was happy given the good vis. I identified him visually, but as he got closer something caused me to get out the binoculars. He was towing something. It was huge, and very low in the water, and a long way behind him. I called him on the radio and asked if he was happy for me to maintain course and speed. He explained that his tow was 6 cables long, and if I altered 20 or so degrees to starboard it would be a bit more comfortable for him. I assured him I would turn to starboard and also reduce speed to ensure I would pass behind his tow, which I did and we were both happy. AIS calculates a CPA between two GPS aerials, and does not always give the full picture.

Radar is also an excellent tool if used correctly, by which I mean that a plot is maintained, rather than just looking at a target on the screen to deduce if you will miss it. Also, most chartplotter radar displays provide MARPA, but this cannot be relied upon due to movement of the aerial up the mast. Another example. Some will remember some years ago a large yacht set off north across the channel and ran into thick fog. It was then in collision with a large container ship, and sank in seconds. The ship had plotted the yacht, which was going to cross in front of him and CPA was the other side at 1.25 miles. The OOW was happy with this. The yacht was fitted with radar, but nobody on board knew how to plot the target. They were eyeballing the screen and as the target got closer and closer they decided at the last minute to slow down. There was not enough time for the OOW on the ship to spot the change in speed and the result was that instead of passing safely in front of the ship, they were in collision with it. They were blamed in the MAIB report because as the yacht was fitted with radar but nobody knew how to use it properly they were not maintaining a watch using "all available means".

If you don't know how to plot a radar target any RYA sea school will offer you a half day course.
 
bbg said:
Read for yourself.http://www.vespermarine.co.uk/marine-safety-products/ais-watchmate-tx.html/#features
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I want one! This looks like an intelligently-designed, easy to use piece of kit. I'm also well-convinced with their sales argument that it avoids the clutter of AIS overlay on a chartplotter (which I don't have).

But, as I first have to buy and fit a DSC VHF (which I also don't have), I'm wondering whether the Standard Horizon combined VHF-AIS unit will be a more cost effective route? Does anyone have experience of this SH kit, especially the ease with which one can automatically select a problem contact and dial a call to their bridge?

There is also the question of whether one needs a transponder (which triples the cost of the Vesper unit)?
 
AIS is brilliant, but you need to be aware that not every vessel transmits AIS data; even if fitted.

RN warships are sometimes a little coy about revealing their position, course and intentions. The cynic in me also reckons when they do transmit they might sometimes be telling porkies.

Fishing boats I am convinced switch AIS off, if fitted, so as not to draw attention to where they're fishing.

Only yesterday I had an AIS target "Deep Sea One", identified as a fishing vessel, a mere half mile ahead. I had a mental image of a large commercial trawler. All I could sea was a small open boat, with a grandiose name, setting lobster pots.:)
 
It is a very big step to get radar. Cost, installation up mast, amps, where can the screen be fitted, etc. Even then, to get the benefit, every watch-keeper needs to acquire quite a difficult skill. And keep in practice.

I'm not getting radar, too many negatives for me at present. But I had little trouble adding and using an AIS receiver. And I am upgrading my AIS to transponder.

Also we do have an Echomax radar target enhancer. Probably better to get that before full radar in my opinion, even though that is a masthead job.
 
Babylon said:
I'm wondering whether the Standard Horizon combined VHF-AIS unit will be a more cost effective route? Does anyone have experience of this SH kit ...
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Yes, we've got that SH combined model, used in cockpit on the optional remote command mike. Very good, you don't need it linked to a plotter, the remote's own tiny screen is good enough to get the AIS benefit. Never had to call up an on-coming ship though.

Come to think of it, in 2 years I've only ever talked on that VHF twice. And they weren't radio checks!
 
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