Got radar, needs AIS as well??

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bluedragon

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This has probably been covered, but I couldn't pick it up in a search.

The boat I've just bought has Autohelm SL72 radar at the chart table, and Raymarine A65 plotter at the wheel. Two questions:

a) Having a radar unit already on board, is there any point in having AIS as well? I think there may be, but that's just a gut feel.

b) If I fitted an AIS receiver, could the A65 plotter display the output, or is it back to the chart table / laptop to view this data?

Ideally I'd like everything in front of me at the helm but don't want to spend a load more money on new kit when the old stuff still works. Thoughts?

Oops...should have put this in the PBO forum!
 
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Both the SL72 and the A65 are incapable of displaying AIS information, so if you want AIS you'll have to have another display. Personally, I'd value radar more highly than AIS.
 
Provided it interfaces with your existing kit, I would get AIS, at just over £100 for a receiver they are almost in the "why not" bracket, just like surely no one would not have VHF or GPS these days. I have both and fitted AIS after the SIBS and put it to use on the scuttlebut Cherbourg trip, yes I know the agruement that not all ships have AIS functional and most yachts and fishing boats dont have it, so you still need radar but it is a great help crossing shipping lanes to have a postive ID on ships and know their course, speed, CPA and TCPA, all of which are difficult to extract from radar unless you are an expert plotter. It was fantastic for crossing the solent in thick fog, passing Cowes I could see exactly which radar target was a Red funnel ferry etc. It was dead easy to fit and immediately interfaced with my SH plotter using a separate aerial.
 
Thanks Chubby, I think you've just put my gut feel into words! Didn't realise they were that cheap...though I guess that's just for the receiver (not a display). So, is it better to have the AIS display alongside the radar (to use / compare the two together?)

PVB - thanks I had a feeling neither would
 
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I have both radar and AIS, and from experience I would suggest the radar comes first, but particularly in the more complicated situations the AIS data can be invaluable. Remeber it gives you after a little time the name,callsign and MMSI number of the target. My AIS failed (full marks to Comar for their replacement service) and there were a couple of times when the info from AIS would have unravelled the scene faster that radar/visual did.

If your kit cannot display AIS info and your budget does not allow replaccing the plotter (I would not have AIS data on the radar) then there is a decent budget display from NASA.
 
Well. Got both radar and ais on different plotters on our boat. Yes radar is supposedly good - when you've learnt how to interpret it. But ais is immeadiate and really handy on deck.

Both our plotters are on deck - radar by the wheel and aid by the companionway. Ideally ais would be by the wheel too but that will come later as we'll have to replace the radar too.
 
bluedragon said:
This has probably been covered, but I couldn't pick it up in a search.
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The built-in search ignores words of three letters and shorter, which is why it won't help with any queries about AIS :(

A better search technique is to use google restricted to only this site - add site:ybw.com alongside whatever you're searching for to do that.

Pete
 
bluedragon said:
a) Having a radar unit already on board, is there any point in having AIS as well? I think there may be, but that's just a gut feel.
!
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I have both and the radar rarely gets turned on, though most of the sailing has been in warmer climes offshore. i have the nasa stand alone unit which does everything i need, favorite bit of kit with decent alarm, uses little power and works down to a low voltage. Between that and an LED masthead I can see lots and be seens by lots, hopefully. :)
Different animal to radar, you can't really compare them.
 
bluedragon said:
This has probably been covered, but I couldn't pick it up in a search.
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I've made some contributions: this was the latest, and this is MY original reason for installing AIS - fast ferries driven by cowboys in my cruising area.

As for AIS vs radar - they are complementary, not a case of one being 'better' than the other. Here is an example where AIS reports a target that radar would not pick up due to the high land between us that would shield the higher frequencies involved (my boat is the large red arrow). No problem in this example but consider a closer constellation with converging courses, when AIS would give warning CPA and TCPA.

Premuda02.jpg

​
 
I know AIS receivers are relatively cheap and very useful, but do you not think it might be nice to allow other folk to see you on AIS as well? If we all fit receive only AIS, there'll be no-one to see other than commercial shipping over 300grt, which might not be so useful when you're heading for a busy estuary in thick fog.

What does everyone else think?
 
dk said:
I know AIS receivers are relatively cheap and very useful, but do you not think it might be nice to allow other folk to see you on AIS as well? If we all fit receive only AIS, there'll be no-one to see other than commercial shipping over 300grt, which might not be so useful when you're heading for a busy estuary in thick fog.

What does everyone else think?
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Well, I personally think it would be self-defeating for all leisure craft to fit an AIS transponder.

Think Sunday on the Solent. It will prompt commercial shipping to filter class B signals out of their systems and for cheaper receivers, which to my knowledge cannot yet do so, to be swamped by targets and consequently miss the important large vessel that really is a threat.
 
AIS in the Solent if you cannot filter out class B is pretty much useless ...
Fortunately my CP180i doesn't show class B ... the laptop does, but that is down below.
 
Thanks everybody. It pretty much confirms my own thoughts. Now to decide whether to go for one with a display, or just feed it into the laptop. Need Navtex as well, so that could also go to the latter. Not ideal to have AIS down below, but as that's where the radar is, maybe it's pragmatically the best solution for now. Need to give that some thought.
 
AIS and Radar are two different tools. The radar needs a lot of practice and skill to use safely to judge CPA. However, the radar will do things that AIS will not, it will tell you how far off that lump of rock is that you cannot see through poor vis. The AIS though will give you information very quickly about shipping that is potentially a threat to your course and allow you to take avoiding action, if need be.

We used to have radar and an AIS 'screen' at the chart table, and a plotter at the helm for pilotage. Not ideal, you need all these tools together, ideally at the helm. On some boats this is difficult, tiller steering for instance. The chart table is for navigation, the helm is for decision making. Especially short handed.

After careful thought I decided I wanted AIS, plotter and radar all in one unit at the helm. At the helm is where decisions are made, this is where you need to be piloting in unfamiliar waters, and during periods of poor visibility or when shipping is about. In the end I bought a new plotter/AIS/Radar that allows me to do just this. What is more it does everything I hoped for, making crossing shipping lanes and pilotage much safer.

As for AIS transponders. In the Solent, I turn off my AIS, so many cruising boats are now transmitting AIS signals, its a joke. If poor vis was to descend, then you turn to your radar, you can easily get into shallower water, out of the way of merchant vessels, and with a good look out and your radar, another cruising boat at 6 knts can easily be picked up. I know, I've done it.
 
LadyInBed said:
I'm pretty sure that my CP180i does, though I have done a firmware update on it.
Saw quite a few yachts transmitting AIS data down round Falmouth this summer.
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Yes - the new firmware does show class B - but still won't let you filter it out (unless they've updated further) - in the Solent that would be a PITA ... and I've not got a switch to turn the AIS engine off ... anyway - it is nice to be able to identify a container ship just leaving Southampton or just approaching the forts ... I just don't want to know that there is another leisure vessel about to collide with me every 10 seconds...
 
Barnac1e said:
Well, I personally think it would be self-defeating for all leisure craft to fit an AIS transponder.

Think Sunday on the Solent. It will prompt commercial shipping to filter class B signals out of their systems and for cheaper receivers, which to my knowledge cannot yet do so, to be swamped by targets and consequently miss the important large vessel that really is a threat.
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Seconded. Anyway, after the Ouzo tragedy the key lesson for me was that we need to keep out of their way, coz they won't be looking out for us even if we are transmitting and have a radar reflector. An AIS receiver enables us to monitor who is around, what is their course. We can even call them up on their MMSI if worried - and that does normally produce a response as we have found.
 
innesker said:
Seconded. Anyway, after the Ouzo tragedy the key lesson for me was that we need to keep out of their way, coz they won't be looking out for us even if we are transmitting and have a radar reflector. An AIS receiver enables us to monitor who is around, what is their course. We can even call them up on their MMSI if worried - and that does normally produce a response as we have found.
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The writing was on the wall long before the Ouzo tradegy, you cannot offload your safety and security to some one else, mainly because they will never place the same level of importance on it as you do.

If you are ina vulnerable vessel you need to be more carefully about who is around you than some one who is in a rather invulnerable vessel.

One of the big changes I have noticed since AIS is the way big ships now talk to each other. The know the other ships name and call them directly. In the old days there was lots of "the ship in front of the big tanker, etc etc and you did hear cases of mistaken identity. Of late I have even heard harbour control calling a ship and telling them their status was incorrect.
 
We had a Radar/Chartplotter at the helm and down below and a NASA AIS down below (not waterproof) and both of them were very useful, the Radar for identifying targets and we always set up the MARPA for anything which might be threatening, whilst the MARPA was useful it was not very accurate so for any vessel which looked to be a problem we would use the AIS to get more accurate data, but what a pain having to keep going below to interpret the AIS data.

We have upgraded to a system which allows us to display the AIS on the chartplotter - what a joy it is we can compare the radar and AIS data in the one display and where AIS data is available we use that in prefernce to any MARPA Radar data as it is much more accurate.

We also have an AIS Transponder which seems to be a useful device as we have been called up a number of times in thick fog by yachts checking that we have seen them on radar

So to sum up in my opinion the NASA AIS system is good and a useful tool, but having the Radar and AIS data integrated in the chart plotter is better.
 
innesker said:
Seconded. Anyway, after the Ouzo tragedy the key lesson for me was that we need to keep out of their way, coz they won't be looking out for us even if we are transmitting and have a radar reflector. An AIS receiver enables us to monitor who is around, what is their course. We can even call them up on their MMSI if worried - and that does normally produce a response as we have found.
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Mentioning the Ouzo in relation to AIS reminds me of the MAIB official report of the incident, I remember taking issue with one of its conclusions, viz., that AIS would not have influenced the outcome:
"AIS is being carried by an increasing number of yachts, partly to assist in their being more “visible”. Had Ouzo carried AIS it would have made no difference to the outcome as AIS information was not displayed on the radar of Pride of Bilbao. This situation should improve as AIS is being integrated into more ships’ systems in the future" ​
This statement raises more questions than it answers but one interpretation is that the Pride of Bilboa probably had only a MKD (Minimum Keyboard and Display) device, the display screen of which is so small that it is not much use as a CPA warning unit, having only a line of text data for each target received; this would be the minimum to comply with the SOLAS regulations.

But more importantly for us small boat sailors, the report failed to consider that the Ouzo could have taken some other action had their crew been better informed, which would have been the case with just an AIS receiver and no transponder. With the callsign, name, position and course of the Pride of Bilbao, including the final and lethal change of course, the crew may have had warning and data enough to have made a lifesaving change of course themselves and/or VHF call to warn the Pride of Bilbao directly of their presence and position.
 
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