Experience With Doppler Radar

[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

[Paul L]

Originally Posted by Dockhead

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.






So true. Great post

Or select the target to be followed with ARPA, then you have a course arrow as well as CPA/TCPA.

[Dockhead]

Originally Posted by Squanderbucks

. . . 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?

On a well-crewed vessel, traditionally, the helmsman was crew only and NOT in charge of the vessel. The skipper or whoever is in charge would be watching the plotter and giving orders to the helmsman.


Nowadays with excellent autopilots there is no need for a dedicated helmsman, and the person in charge would often be at the helm in complicated situations where having a display there is really useful. Nevertheless, many boats still mount their instruments under the spray hood, rather than at the helm itself.

[Dockhead]

Originally Posted by Paul L

Or select the target to be followed with ARPA, then you have a course arrow as well as CPA/TCPA.

Sure, if you HAVE ARPA. I do not, and the crappy MARPA on my B&G system is utterly useless. By the way, with true ARPA you don't even have to select the target -- it's acquired automatically.



Yes, ARPA if it really works is the killer app for this. Furuno anyone?


The rest of us have to make do with the VRM and EBL.

[Paul L]

Originally Posted by Dockhead

Sure, if you HAVE ARPA. I do not, and the crappy MARPA on my B&G system is utterly useless. By the way, with true ARPA you don't even have to select the target -- it's acquired automatically.



Yes, ARPA if it really works is the killer app for this. Furuno anyone?


The rest of us have to make do with the VRM and EBL.

On my Furuno setup ARPA only automatically picks up targets within guard zones, so for targets outside that I am interested in I left click on the blip and a target is tracked. This is usually the case when I am trying to gather target info for planning a passing.

[Dockhead]

Originally Posted by Paul L

On my Furuno setup ARPA only automatically picks up targets within guard zones, so for targets outside that I am interested in I left click on the blip and a target is tracked. This is usually the case when I am trying to gather target info for planning a passing.

In any case, that's a superior implementation. One reason why I seriously consider Furuno for my next boat.


I can't say it's a "must have" for me -- big majority of targets of interest are on AIS, VRM shows very well whether range is increasing or decreasing, and EBL shows very well the relative motion so whether you're on a collision course, without needing to do an actual radar plot. This only breaks down in the kind of situation you describe -- where you have multiple potentially dangerous targets at once. That must be fairly rare, but yes, well implemented ARPA is the killer app for that.

[Orion Jim]

Last year was my first season with a Garmin Fantom Doppler Radar and it was very intuitive when compared with my previous mid-eighties generation Raymarine unit. The technology has really matured during those years. Must compliment Raymarine, never had any issues in all those years of use. Hope to get the same from my Garmin unit.

[RaymondR]

Originally Posted by Dockhead

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.

The two screen at the helm arrangement is partially a result of a fairly constant desire for redundancy by an old, single handing dude with a strong desire for a stress free as possible existence (In addition one of them has Navionics and the other Cmap charts) However, having now experienced the plethora of information available at a glance without constant screen shuttling, it's an arrangement I would recommend to other single handing geriatrics struggling with the new electronics age.

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.

During the south going leg of my winter cruise I traversed a stretch of coast with 7 metre tides which occasion some pretty fierce tidal runs. For one of the legs the northerly winds required an anchorage within an island group from which, because of the need to round a cape to the east and the tide times I was needing an exit in the dark of the night. The winds ease back during the night and I was hopeful that I would be able to get around the cape against the NE wind at the top of the tide during slack water.

Having found the right menus and bits of the screen to touch I managed to get the radar image to overlay the chart and was exceptionally pleased with the result. It is a fantastic confidence builder to be able to observe that the actuality of the radar images position exactly mirrors that of the chart plotter whilst I wended my way around the various islands to clear the anchorage.

I almost made it to the cape but the wind freshened and I was obliged to an alternate route south and then east through a place called Strong Tide Passage, which I was able to traverse at slack water.

So in addition to being a big fan of the dopler colouring of moving targets I am also a big fan of the ability to overlay the radar image onto the chart plotter image with the radar image automatically scaling to the moving map image.