Experience With Doppler Radar

[RaymondR]

A couple of years ago I did a boat upgrade. The new to me boat came with a Furuno greyscale radar which I tended not to use very often as it is at the nav station and I am a single hander.

In 2017 during my winter ctuise to the tropics I was passing south and had to make a night passage through a mass of anchored ore carriers at anchor off a coal loading terminal. Because of the vast and confusing plethora of lights I decided to switch on the radar to see if it might assist to de-confuse me. It takes about a minute to warm up and took me another minute or two for me to decide that unless I chose to continuously monitor it, it was of no assistance.

On moving back to the helm I found about a 300,000 tonner passing across my bow a few hundred yards ahead. Mucking about with the radar when I should have been on the wheel might have gotten me run down.

On pondering upon the incident I decided that it would not really have helped even had I remounted it at the helm position as, in the situation I was in, I would not be able to give it the constant attention an interpretation of what was displayed on the screen required. However I also tended to the opinion that because of the ranging of the contacts displayed on the screen radar could contribute to safer navigation in that type of situation.

On perusing marine equipment catalogs I had noticed "dopler" radars but, not being greatly interested, had not evaluated their capabilities. Doing so I realized that one of these displayed at the helm could be of great assistance and consequently purchased a Raymarine product.

I had upgraded to a 9" MFD about twelve months previous to purchasing the radome but found that it had a serious software problem. The subsequent warranty work delayed the installation and I did not check whether or not until yesterday. My first great surprise was that it all worked perfectly and the screen in the attached image came up.

Noticing the red dot on the port bow I glanced in that direction a saw a jet skier about 3/4 nm away. When he went past at about the same distance it turned into a green dot exactly as the description in the brochure had described it would.

I was still following a northerly course after dark last night and came across three prawn (shrimp) trawlers working in proximity across my intended course. These things are always a problem to navigate in proximity to as their intense deck lights tend to obscure their nav lights making it v ery difficult to ascertain their course and since they also blind their helmsmen they tend not to see other vessels.

Rather than just a mass of whitish blobs the dopler radar defined each of them as potential hazards, red, or of little consequence, green and the passage was completely without stress.

Love my new dopler radar after only the first date.

[slug]

It takes time..experience behind the screen .. to understand , tune and interpret radar

The old style grey radars work perfectly

No Need to fall for the latest marketing and purchase a new gee wizz gizmo

Additionally ... the modern radars with all the various overlay features ..are distracting and not needed

I prefer stand alone chart plotter Ais

Stand alone radar

[RaymondR]

Originally Posted by slug

It takes time..experience behind the screen .. to understand , tune and interpret radar

The old style grey radars work perfectly

No Need to fall for the latest marketing and purchase a new gee wizz gizmo

Additionally ... the modern radars with all the various overlay features ..are distracting and not needed

I prefer stand alone chart plotter Ais

Stand alone radar

Or one can accept the vast improvements in usability that modern digital electronics and data processing confers and adopt it for safer, less stressful boating.

I also got some waypoints from the local volunteer marine rescue folks to put into my MFD and had a far less stressful bar crossing than last time so I'm definitely a serial offender.

[Minggat]

Originally Posted by RaymondR

Or one can accept the vast improvements in usability that modern digital electronics and data processing confers and adopt it for safer, less stressful boating.

I also got some waypoints from the local volunteer marine rescue folks to put into my MFD and had a far less stressful bar crossing than last time so I'm definitely a serial offender.

I am going to upgrading soon, so it's good to hear what others appreciate in their choices.

[RaymondR]

Originally Posted by Minggat

I am going to upgrading soon, so it's good to hear what others appreciate in their choices.

In Australia and from the most extensive mail order, recreational marine, supplier the listed price for the non dopler radome was $2,249 and for the dopler $2,649 or $400 more. I consider the very significant improvement in situational awareness conferred by the dopler colour coding of targets to have been well worth the $400 extra.

[Squanderbucks]

I have a Garmin Fantom 24 which is their Doppler Radar and love it. The colors make it much faster to decent things but Doppler works for moving things. Stationary item still require you to evaluate the whole image but at least the Doppler cuts down on the ifs and maybes.

As a power boater I have never understood why nav equipment was put on any boat and not available at the helm or for that matter every helm.

What is the point if you can’t see the chart, depth, etc where you are piloting from.

I use planning software at home or on tablets but that is not the same as knowing data on the spot.

Why not have nav data at the helm?

[redneckrob]

Originally Posted by slug

It takes time..experience behind the screen .. to understand , tune and interpret radar

The old style grey radars work perfectly

No Need to fall for the latest marketing and purchase a new gee wizz gizmo

Additionally ... the modern radars with all the various overlay features ..are distracting and not needed

I prefer stand alone chart plotter Ais

Stand alone radar

I spent a couple years dealing with the old AN/SPS-64 to the point I was as proficient as it's possible to be on a radar. And I can't believe why anyone would advocate for continuing to use something that provides inferior situational awareness, increased chance for confusion, and generally crappy target resolution and clutter rejection when far better options are available. A model T also works perfectly, but not for nothing not many of us are still using one to get to work every day.

[roland stockham]

What has put a lot of people off yatch radar is that lots of very small array unstabilised radar wher fitted. the result is large blobs dancing all over the screen that are very hard to interpret. Compair that to a 24 inch stabilized set and you see why all commercial boats use them. I may be that new tech has brought this quallity to smaller array sizes now.

[RaymondR]

I'm learning how to use it by having it on during daylight as I coastal cruise which provides a plethora of returns environments and the more I use it the more impressed I'm becoming with it's ability to discriminate and display targets. The color coding of moving targets brings one's attention immediately at a glance and the target displays on screen appear to be very well related to the size of the target. It is picking up all the nav markers both buoys and fixed on poles.

One of the reasons I decided to try the upgrade was that coastal cruising often requires one to enter anchorages after dark and whilst the chart plotter does a good job of placing the vessel in relation to permanent features it doesn't help at all with anchor light free vessels, dingies on long painters etc. However I'm fairly certain that when I get the radome properly adjusted for angle and have gained interpretive skills via daylight usage it will become a valuable aid to navigation in these circumstances.

[a64pilot]

Originally Posted by Squanderbucks

I have a Garmin Fantom 24 which is their Doppler Radar and love it. The colors make it much faster to decent things but Doppler works for moving things. Stationary item still require you to evaluate the whole image but at least the Doppler cuts down on the ifs and maybes.

As a power boater I have never understood why nav equipment was put on any boat and not available at the helm or for that matter every helm

What is the point if you can’t see the chart, depth, etc where you are piloting from.

I use planning software at home or on tablets but that is not the same as knowing data on the spot.

Why not have nav data at the helm?

I think it comes from back in the day it was large and fragile, needed a CRT for instance and that just doesn’t fit at the helm, just like when I was a kid a decent fish finder was a chart recorder with two rolls of paper, it was that or a flasher, a chart recorder wasn’t going to fit at the helm either.
Now we have thin, flat MFD’s that will fit at the helm, and it makes more sense to have them there.
That is where mine is, and I repeat the signal over WiFi to an IPad below decks, so in theory when I’m off watch I can still see what’s going on.
I say theory as we are a couple only, and realistically only Coastal Cruise, so I’m always on watch .

However don’t be too reliant on Doppler discerning a Moving target from a truly stationary one if it’s a slow mover, even the multi million dollar Longbow Fire control Radar sometimes missed a slow mover

[BMD21]

Well, to learn how to use radar, one has to use it. This means turning on the radar in daylight, seeing what's on the screen and comparing it with reality. Use the adjustments and see what they do. Radar overlay is almost mandatory since one can see what returns are with what nav aid.


You might look at the Lowrance line of small radars which use transistors for power instead of a magnetron. This means they transmit at low power levels and have a good return at range which mean something to a sailboat, I have a 3G and the return is wonderful. Overlay is enabled with a Point1 GPS ($200) and works fine. The 4G has a few more bells and whistles that the 3G, but I've never missed them. Actually, the Lowrance HALO 20+ ($2200) now does pulse compression via fast Fourier transforms. This allows good performance at both close and far ranges (36 nmi.) Another advantage is instant on, but if you're in that much of a hurry, you've waited too long.


Another benefit of using Navionics radar is that the connection is via ethernet. This means one can run the radar cable into an internet router and feed both a OpenCpn PC and the Lowrance/Simrad/B&G MFD with radar at the same time. Thus the PC can serve as ones 15" main display or as a backup to ones MFD.


Boris

[RaymondR]

Originally Posted by a64pilot

I think it comes from back in the day it was large and fragile, needed a CRT for instance and that just doesn’t fit at the helm, just like when I was a kid a decent fish finder was a chart recorder with two rolls of paper, it was that or a flasher, a chart recorder wasn’t going to fit at the helm either.
Now we have thin, flat MFD’s that will fit at the helm, and it makes more sense to have them there.
That is where mine is, and I repeat the signal over WiFi to an IPad below decks, so in theory when I’m off watch I can still see what’s going on.
I say theory as we are a couple only, and realistically only Coastal Cruise, so I’m always on watch .

However don’t be too reliant on Doppler discerning a Moving target from a truly stationary one if it’s a slow mover, even the multi million dollar Longbow Fire control Radar sometimes missed a slow mover

I've noticed the problem with very slow moving targets and wondered if there was an adjustable threshold somewhere in the settings.

I can monitor the A7 on my tablet using a Raymarine app but have not tried to connect to the Axiom 9" which is the one with the radar on it. Future project.

I also have found that whilst it will pick up almost anything metal it has problems with the more modern fibreglass boats with all radiused corners even to fairly large cruisers.

I am now in a river with a lot of moored boats which are not required to have any lights. The good target discrimination I am observing is tending me towards a degree of confidence that it will be a valuable tool in entering and leaving anchorages on dark nights.

In crossing the Wide Bay Bar I noticed it showing breaking waves about one mile away as moving targets but there was no ground clutter from the building swells before they broke.

It gave very strong returns on the metal nav markers mounted on poles. These things are very difficult to make out against the dark green and shadows of the mangroves.

[Dockhead]

Originally Posted by slug

It takes time..experience behind the screen .. to understand , tune and interpret radar

The old style grey radars work perfectly

No Need to fall for the latest marketing and purchase a new gee wizz gizmo

Additionally ... the modern radars with all the various overlay features ..are distracting and not needed

I prefer stand alone chart plotter Ais

Stand alone radar

Well, to each his own. But radar overlay on a chart is a fantastically useful function, giving you full radar navigation at a stroke, and besides that giving you a way to check the chart accuracy and your position accuracy continuously. The other really useful function on modern radars is effective guard zones, which work much better with newer radars because of improvements in DSP. The Doppler function the OP is talking about is probably also a pretty meaningful enchancement to interpreting the radar picture, even if it doesn't tell you anything that a decent radar operator can't figure out. But it reduces the work load, and that's always good on a short handed vessel.



Standalone radar is great, but who has room for two screens at the helm? It's much more convenient to operate both radar and plotter from the same device.

[RaymondR]

The usability of the new radar being mounted at the helmsmans (or helmswomans) position beside the chart plotter is so vastly improved that I would never again have it any other way.

My practical experience with the prawn (shrimp) trawlers during the night encounter firmly convinced me of the value of the dopler driven colour coding of moving targets entirely convinced me of the value of this function.

Three non colour coded targets working in close proximity directly on my course line would normally require a lengthy course diversion had I the room to make one. However the trawlers were working across the mouth of the bay in which I wanted to anchor and consequently I was obliged to pass through them.

These things have trawls which follow them hundreds of metres astern and if you cannot ascertain their course direction judging where to pass safely astern of the trawls is very stressful.

Although my experience with the new radar is yet fairly limited I already highly value the functionality of the colour coded targets.

From the viewpoint of distractions.

The biggest and possibly worse distraction for the single hander when working in proximity to other vessels or in narrow waters is the struggle to maintain situational awareness. Being able to ascertain the situation in relation to geographical position and other vessels at a glance with good instrumentation is a great advance in safe navigation.

[Dockhead]

Originally Posted by RaymondR

The usability of the new radar being mounted at the helmsmans (or helmswomans) position beside the chart plotter is so vastly improved that I would never again have it any other way.

My practical experience with the prawn (shrimp) trawlers during the night encounter firmly convinced me of the value of the dopler driven colour coding of moving targets entirely convinced me of the value of this function.

Three non colour coded targets working in close proximity directly on my course line would normally require a lengthy course diversion had I the room to make one. However the trawlers were working across the mouth of the bay in which I wanted to anchor and consequently I was obliged to pass through them.

These things have trawls which follow them hundreds of metres astern and if you cannot ascertain their course direction judging where to pass safely astern of the trawls is very stressful.

Although my experience with the new radar is yet fairly limited I already highly value the functionality of the colour coded targets.

That makes sense to me. I don't have Doppler radar, so the way I would handle such a situation is to set a VRM on the nearest target. If something is getting closer, you'll see that in a few sweeps in relation to the VRM.


But the color coding would be even better, and less work. Work load is very important on a short handed vessel -- one person can get quickly overwhelmed with a really tricky traffic situation.

Originally Posted by RaymondR

From the viewpoint of distractions.

The biggest and possibly worse distraction for the single hander when working in proximity to other vessels or in narrow waters is the struggle to maintain situational awareness. Being able to ascertain the situation in relation to geographical position and other vessels at a glance with good instrumentation is a great advance in safe navigation.

So true. Great post