AIS Class A & B v Radar

Jurgen

Jurgen

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Am considering a full electronics update with latest Raymarine kit, currently have Radar but not AIS

Would do the occasional Chanel Island trip but 99% of boating is in the Solent

My thoughts are that based on my boat use AIS might be a better investment than Radar, the only downside to not having Radar that I can see is that it might put off future owners?

What are folks thoughts?
 
It's an interesting debate. Certainly AIS is more immediate for the big ship stuff (which is liely to be your biggest threat) and requires no interstate on. I've used it across the channel and it's brilliant.

Radar, a nice to have. If it was one or the other I think I will go AIS
 
The consensus from those here with first hand knowledge of commercial shipping seems to be that AIS transmit is not worth having on small boats - the bridge crew on commercial ships tend to filter out class B AIS, so they will not see you. We have AIS receive hooked up to the plotter and are intending to fit radar to compliment it. AIS receive will warn you of ships nearby, but it will do nothing to warn you of other passive obstructions or assist with navigation.
 
maby said:
The consensus from those here with first hand knowledge of commercial shipping seems to be that AIS transmit is not worth having on small boats - the bridge crew on commercial ships tend to filter out class B AIS, so they will not see you. We have AIS receive hooked up to the plotter and are intending to fit radar to compliment it. AIS receive will warn you of ships nearby, but it will do nothing to warn you of other passive obstructions or assist with navigation.
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My experience is to the contrary.
A couple of years ago, SWMBO and I were doing a night crossing from mainland Spain to the Baldricks.
We carry both radar and transmit AIS.
We were on a collision course with a large ship so I switched on AIS target tracks.
We were the "stand on" vessel.
It was very clear from the resulting track that the large ship altered course to starboard and then back to his original heading.
This was all within five miles and we were the only two vessels in the immediate area.
The course alteration could only have been to avoid us.
 
AIS is good but it doesn't replace radar imho. There are plenty of things you can hit that are not transmitting AIS. You don't usually need radar in good weather and daylight but if you contemplate night running then AIS is nowhere near a substitute for radar imho.
 
Rocks don't transmit AIS and, if going near them in limited vis including during hours of darkness, I'd always want radar.

AIS is great to have as well of course.
 
Different animals completely.

AIS gives you the ability to be seen for what you are ( a Liesure boat travelling at x knots) an if a receiver fitted for you to see others eg Brittany Ferries Armorique travelling Sw at 20 knots.

Bear in mind a lot of fishing boats either don't have AIS or turn it off so others can't see where they are fishing.

i don't have AIS yet but will soon, radar is anti collision now and port entry in fog, one does not replace the other.
 
I have both. Interestingly I rarely turn the radar on (but it is there as a valuable tool if the need arises), but I am constantly monitoring the AIS triangles on my plotter. £ per mile, the AIS has been a well used investment and I like the fact that I can radio a specific ship with MMSI, callsign or name based on the AIS data if needed. The other advantage is that friends and family can monitor my progress on Marinetraffic etc.
 
Keith-i said:
I have both. Interestingly I rarely turn the radar on (but it is there as a valuable tool if the need arises), but I am constantly monitoring the AIS triangles on my plotter. £ per mile, the AIS has been a well used investment and I like the fact that I can radio a specific ship with MMSI, callsign or name based on the AIS data if needed. The other advantage is that friends and family can monitor my progress on Marinetraffic etc.
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+1 word for word!
 
jfm said:
AIS is good but it doesn't replace radar imho. There are plenty of things you can hit that are not transmitting AIS. You don't usually need radar in good weather and daylight but if you contemplate night running then AIS is nowhere near a substitute for radar imho.
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+1. AIS is not a substitute for radar. Radar is as much a pilotage tool as to "see" other vessels etc. radar will get you into a harbour in restricted viz, AIS won't!
 
Solitaire said:
+1. AIS is not a substitute for radar. Radar is as much a pilotage tool as to "see" other vessels etc. radar will get you into a harbour in restricted viz, AIS won't!
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You want to try cruising in the Med
The radar has far less use than in UK waters.
We really only use ours on the longer passages whereas the AIS is used all the time - and even socially to let friends know where you are.

On another point - in favour of AIS
I remember clearly, arriving for the first time this year at Carloforte.
We followed one of the ferries in and just just at the entrance to the harbour, the ferry stopped.
I was confused so I looked at the plotter showing AIS and it showed another ferry leaving - completely obscured by the first ferry.
The Radar was useless in this case - like me, it couldn't "see through" the first ferry - OTOH the AIS gave a very clear picture of what was happening.

Guys, you have to use these things to realise which is best.
Yes - I agree with you that I want both but the OP was asking AIS vs Radar
I'm afraid AIS wins every time for me.
If I had to choose from only one - I'd choose AIS.

Yes, you can use radar for navigation as well as collision avoidance but how many of us have ever done so and know what to do.
 
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Why not both? In the grand scheme of a full electronic refit, and AIS transceiver is small and trivially cheap - the Raymarine AIS650 can be had for under £600 and the one I have cost half that.
 
Hurricane said:
Yes, you can use radar for navigation as well as collision avoidance but how many of us have ever done so and know what to do.
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Not rocket science to, say, use radar to keep a constant and known to be safe offing.

I agree with the more general point that much of the time radar won't be needed whereas AIS is always interesting. I'd always have both :D but, if it had to be just one it would be radar.
 
Hurricane said:
Yes, you can use radar for navigation as well as collision avoidance but how many of us have ever done so and know what to do.
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Traditional radar nav can be quite intense, and needs skills and practice as you say. But a plotter overlaying the radar picture on a chart changes the game - it provides a constant cross-check on the GPS, the chart datum, and most of the other possible errors, meaning that as long as the radar features line up with the charted features you can "drive the little boat across the screen" with a clear conscience.

Pete
 
Having read all of the varied and meaningful posts ais would have been my choice but the last post re radar overlay is an interesting point.

Cost is an issue in my choice so will have to raid swmbo's purse ?
 
prv said:
Traditional radar nav can be quite intense, and needs skills and practice as you say. But a plotter overlaying the radar picture on a chart changes the game - it provides a constant cross-check on the GPS, the chart datum, and most of the other possible errors, meaning that as long as the radar features line up with the charted features you can "drive the little boat across the screen" with a clear conscience.

Pete
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There is little point in overlaying radar over the plotter as a navigation aid.
It isn't that accurate anyway.
My point was using radar on its own as a navigation tool.
This was assuming that a GPS plotter was no longer available.
Few people realise that angular measurements with radar are as useful as a chocolate teapot.
Radar is most accurate at measuring distance so navigating with radar (without a plotter) would be like taking a visual bearing but plotting your position on a paper chart using distance rather than angular measurements.
As I say, who has ever done this and can you ever imagine doing it.
I have so many backup GPS/Plotter systems that navigating using radar alone is extremely unlikely.
IMHO radar is best used for collision avoidance - and at night or in fog it becomes very useful.
BTW we have been cruising in the Med for 6 years now - never had any fog that would have required a radar watch.
As I say above, radar is nice to have but you get far more "bank per buck" out of AIS than out of radar.
 
Picking up on hurricanes point re fog and night passage that would be the only time we would use radar.

We came back from Guernsey a few years ago and ais would have been very welcome as the sea fog rolled in ?
 
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