Doppler radar - useful or not?

[[2574]]

We’re in the market for a new radar. It’s been twenty years since we last bought this type of kit so we are seeing some changes! The jury is presently out on whether Doppler radar is worth the additional cost. There are some historic threads on here on the subject but nothing for a couple of years. I’d he grateful to hear opinion especially from those who have dug deep to find the extra money - any buyers remorse?

 

[dunedin]

Yacht Radar has certainly improved hugely over the past 20 years. BUT cross brand compatibility of radar and MFD / plotters generally has not.
Are you planning to replace everything, in which case you are free to choose radar brand, or have you an existing recent MFD / Plotter that you want to connect to, in which cases your choices are much more limited?

 

[boomerangben]

I’m not familiar with yachting radar but sit behind one at work. Ours uses Doppler to assess rain fall particularly turbulence with in clouds. I guess in the small boat theatre, it’s for collision avoidance of other moving targets? I thought that’s what simpler radars managed to resolve with lesser accuracy but accurate enough? I’m interested in seeing what those in the know have to say……

 

[[2574]]

Yacht Radar has certainly improved hugely over the past 20 years. BUT cross brand compatibility of radar and MFD / plotters generally has not.
Are you planning to replace everything, in which case you are free to choose radar brand, or have you an existing recent MFD / Plotter that you want to connect to, in which cases your choices are much more limited?

Staying with Raymarine but have ST1 and STng spliced with interfaces to NMEA 0183 for VHF then hi speed 38400 baud NMEA 0183 for AIS.

 

[[2574]]

I’m not familiar with yachting radar but sit behind one at work. Ours uses Doppler to assess rain fall particularly turbulence with in clouds. I guess in the small boat theatre, it’s for collision avoidance of other moving targets? I thought that’s what simpler radars managed to resolve with lesser accuracy but accurate enough? I’m interested in seeing what those in the know have to say……

Yes I gather that Doppler has its main use in meteorology. In small boat radar it’s about automatic identification of targets and reporting of speed/direction of the target to the user. Similarities with MARPA but the latter is not automatic, at least I think that is the difference but stand to be corrected by someone better informed.

 

[dunedin]

Staying with Raymarine but have ST1 and STng spliced with interfaces to NMEA 0183 for VHF then hi speed 38400 baud NMEA 0183 for AIS.

Unfortunately I haven’t got the doppler on our radar. But the basic Quantum is already massively better than the 2000 generation kit on our previous boat. And if your boat is based in the West of Scotland, there will be relatively few targets so not sure the extra collision avoidance benefit of Doppler would be a major factor.
We sailed blind quite a few times this season with radar and AIS on, with radar mainly to check for any yachts or fishing boats hidden in the fog. The main issue is small GRP boats with minimal echo. Would Doppler help there?
What generation, and size, of Raymarine plotter are you expecting to display on?

 

[johnalison]

I replaced my 2000 radar about ten years ago with an e7 and ‘digital’ antenna, but it works in a fairly basic mode. For what I have needed, this has been entirely adequate. I have really only wanted it for collision avoidance in open water and not for detailed work inshore or for navigation. If I were to replace mine, which I won’t, it would be for one with a much smaller current drain, and with my total of about 200 Ahr of battery that would be my priority, and then it would be merely a matter of what display unit I was getting.

 

[[2574]]

Unfortunately I haven’t got the doppler on our radar. But the basic Quantum is already massively better than the 2000 generation kit on our previous boat. And if your boat is based in the West of Scotland, there will be relatively few targets so not sure the extra collision avoidance benefit of Doppler would be a major factor.
We sailed blind quite a few times this season with radar and AIS on, with radar mainly to check for any yachts or fishing boats hidden in the fog. The main issue is small GRP boats with minimal echo. Would Doppler help there?
What generation, and size, of Raymarine plotter are you expecting to display on?

New Axiom Pro MFD. Yes we‘re cruising West Scotland and I concluded the same - little traffic therefore minimal benefit. I think I’ll concentrate on getting a decent MARPA setup with a fast heading compass, that coupled with AIS is more than adequate. It’s a useful £350 saving on the radome.

 

[[2574]]

I replaced my 2000 radar about ten years ago with an e7 and ‘digital’ antenna, but it works in a fairly basic mode. For what I have needed, this has been entirely adequate. I have really only wanted it for collision avoidance in open water and not for detailed work inshore or for navigation. If I were to replace mine, which I won’t, it would be for one with a much smaller current drain, and with my total of about 200 Ahr of battery that would be my priority, and then it would be merely a matter of what display unit I was getting.

We have more battery reserves, 750ah, but nonetheless I’m keen on minimising current drain. I understand these new solid state radars use less juice and also are instantly ready - no warm up period, hence can be left off until needed.

 

[Goldie]

Similarities with MARPA but the latter is not automatic, at least I think that is the difference but stand to be corrected by someone better informed.

Is Doppler essential? No (imho). Is it useful? Yes - especially for the less experienced operator.

Regarding Robih’s reference to MARPA, the adoption of primary radar targets and superimposing MARPA type data is indeed automatic (at least, it is on our Furuno radar, interfaced with a plotter running Maxsea TimeZero) for up to 100 targets within a configured guard zone. Primary (i.e. ‘raw radar’) targets outside that zone can be selected and added manually. In addition, any targets closing on your yacht to within a pre-determined range at a closing speed of >3kts (IIRC) are highlighted by a colour change of the radar contact (from green to red on my system) regardless of whether the radar return has been adopted or not. When the system has adopted a radar contact, information such as a vector line, course, speed, CPA etc. are displayed so apart from ID etc. effectively, most of the useful information provided by an AIS transmitting target.

I hope I’ve described that ok!

As an ex professional radar operator for 30+ years (albeit in a different environment), I’m happy with or without Doppler (but wish it had been available when I was working!). My wife, without a radar background, absolutely loves it. The plus side for me is that when she’s on watch alone in the middle of the night, I no longer get woken for advice, even when the radar picture is very busy ?.

Edit: just to add that with fishing fleets in particular, AIS is often not transmitted but the vector lines provided by the system are invaluable in working out which contacts are doing what.

 

[[2574]]

Is Doppler essential? No (imho). Is it useful? Yes - especially for the less experienced operator.

Regarding Robih’s reference to MARPA, the adoption of primary radar targets and superimposing MARPA type data is indeed automatic (at least, it is on our Furuno radar, interfaced with a plotter running Maxsea TimeZero) for up to 100 targets within a configured guard zone. Primary (i.e. ‘raw radar’) targets outside that zone can be selected and added manually. In addition, any targets closing on your yacht to within a pre-determined range at a closing speed of >3kts (IIRC) are highlighted by a colour change of the radar contact (from green to red on my system) regardless of whether the radar return has been adopted or not. When the system has adopted a radar contact, information such as a vector line, course, speed, CPA etc. are displayed so apart from ID etc, most of the useful information provided by AIS.

I hope I’ve described that ok!

As an ex professional radar operator for 30+ years (albeit in a different environment), I’m happy with or without Doppler (but wish it had been available when I was working!). My wife, without a radar background, absolutely loves it. The plus side for me is that when she’s on watch alone in the middle of the night, I no longer get woken for advice, even when the radar picture is very busy ?.

Edit: just to add that with fishing fleets in particular, AIS is often not transmitted but the vector lines provided by the system are invaluable in working out which contacts are doing what.

That’s very interesting that your non-radar professional wife finds Doppler invaluable as I am surely also a non-professional radar operator. So Doppler is good for the inexperienced radar user?

 

[Goldie]

That’s very interesting that your non-radar professional wife finds Doppler invaluable as I am surely also a non-professional radar operator. So Doppler is good for the inexperienced radar user?

It certainly makes interpretation of relative motion and speeds, headings and CPA of non-AIS equipped radar contacts so much easier. In the ‘old’ days, it would have taken some time to come up with manual plots on a piece of paper, now it’s all presented in front of you. However, whether it is worth paying extra for, may be influenced by your sailing environment. With the fishing fleets off the French, Spanish and Portuguese coasts, we find it invaluable. Closer to home, entering the Helford River in poor vis the radar showed a ‘red’ return appearing from right of the bow - it turned out to be a kayaker who otherwise, we might not have seen until very late. If however, you sail in a low traffic density area, the benefits may be less and in my several years sailing on the W. Coast of Scotland a few years ago, I don’t recall much in the way of night sailing or particularly poor visibility.

I’d caveat my input by pointing out that the functionality described is what’s on our system and may or may not be the same with Raymarine, B&G, Garmin et al.

Would I pay your quoted £350 extra for Doppler? If your chosen system offers the functionality to which we’ve become accustomed, and my sailing environment and intentions justified it, then yes I would.

 

[oldgit]

Watched a demo last night on both Garmin and Raymarine set ups.
This technophobe was impressed.
Those red and green blobs made life a little bit easier.

 

[GHA]

Yes I gather that Doppler has its main use in meteorology. In small boat radar it’s about automatic identification of targets and reporting of speed/direction of the target to the user. Similarities with MARPA but the latter is not automatic, at least I think that is the difference but stand to be corrected by someone better informed.

Yet to be used in anger but I went for a halo+ into raspberry pi which includes doppler (& 36Nm range instead of 24nM for the standard halo) but also can be set up as 2 radars, should be very useful offshore solo. 1 set up with alarms for traffic & 1 longer distance to alert for squalls (get the shampoo out ?) .

 

[johnalison]

I have not used, or even played with, doppler radar, but I assume that the additional information shows whether a target is moving relative to your boat. At a much more basic level, I use 'wakes' to serve the same function, and usually have them switched on.

 

[[2574]]

I have not used, or even played with, doppler radar, but I assume that the additional information shows whether a target is moving relative to your boat. At a much more basic level, I use 'wakes' to serve the same function, and usually have them switched on.

Yes, I think that’s right. It’s clever how fixed structures such as a quay wall is distinguished from targets that are moving. So I can see that in a dark, busy and strange harbour the Doppler could be very useful. Whether it’s worth the cost is another matter. Arguably AIS does the same thing - but only for vessels transmitting! I can see that in amongst a non-AIS fishing fleet at night it would help with comprehension of what can be a very confusing situation.

 

[Daverw]

Did not look at Doppler option when we fitted 2 years ago, Radar with AIS both overlaid on plotter seem to cover all needs, current draw is so low with digital units you don’t even notice it.

 

[Ian_Rob]

We are still learning to use our doppler radar but it seems to me that even if you are ‘glued’ to the display it is often quite difficult to quickly distinguish a target that is moving amongst a field of fixed targets. If you suspect a target has moved, it often takes several further sweeps of the radar to be sure - not least because targets aren’t always picked up on every sweep. The fact that a particular return has turned red (or green) just speeds up the process and is particularly helpful when one can only look at the display periodically.

 

[[2574]]

We are still learning to use our doppler radar but it seems to me that even if you are ‘glued’ to the display it is often quite difficult to quickly distinguish a target that is moving amongst a field of fixed targets. If you suspect a target has moved, it often takes several further sweeps of the radar to be sure - not least because targets aren’t always picked up on every sweep. The fact that a particular return has turned red (or green) just speeds up the process and is particularly helpful when one can only look at the display periodically.

Interesting. I’m beginning to think that I might regret not spending the (proportionally) small additional amount to have Doppler. I particularly like that it aids interpretation for the infrequent user of radar - which is me. Also that it gives an immediate representation of what is going on around the boat (as described above) rather than waiting several paints before a picture might become clear. Not much value in the empty waters of West Scotland but we won’t always be there. The decision becomes more difficult….

 

[jlavery]

I've been making sure to get familiar with ("play with" according to my wife ) our doppler Raymarine Quantum. The point being to be used to interpreting it with reference to what I can see going on, before really needing it.

I've found the doppler feature useful. Gives that extra bit of information relating to what might be hazards.