Poll on use of Radar ARPA/MARPA feature

[twistedtree]

I'm curious how many people, when using their radar, make use of the ARPA/MARPA functions. It allows you to "acquire" and track a target, showing the targets speed and direction. If you have radar, please take the poll.

 

[Capt.Bill11]

You'd be crazy to have it and not make use of it.

 

[N4712]

I use it.

 

[Northern Spy]

Radar, but no ARPA or MARPA feature.

PS: Didn't want to be considered "crazy".

 

[twistedtree]

I've found that lots of people don't use it, or even know what it is, hence the poll.

 

[Insequent]

My AIS plots on the radar display as well, it is simpler to just click on the AIS target than to use the radar functions.

 

[caltexflanc]

My AIS plots on the radar display as well, it is simpler to just click on the AIS target than to use the radar functions.

No that many targets have AIS. I use ARPA when there are targets out there I am particularly interested in tracking, but not just for the sake of using it. Great tool.

 

[Sailor of Fortune]

Anything with a 3 mile or smaller CPA gets tracked at sea. Whatever you comfort level will determine.

 

[ksanders]

My AIS plots on the radar display as well, it is simpler to just click on the AIS target than to use the radar functions.

Thats what I do as well.

Before AIS I never used the feature either, even though it is on my Furuno Radar.

I watch the targets around use the echo trail function to get an idea of the targets course

 

[dimer2]

No on the ICW, yes offshore but normally only if it appears to be a concern

 

[Marin]

Our Furuno NavNet VX2 does not have ARPA but it does let you keep manual track of the bearing and range to two targets simultaneously. We have used this feature occasionally when boating in fog.

 

[av8r]

Yes we use it. In the fog to avoid both BC and Washington State ferries, and in good weather to keep in practice.

 

[MYTraveler]

If you don' use it offshore, you probably don't know what you are missing. Note that the A means automaric -- one need only enable.

 

[tpbrady]

When I upgraded my autopilot I lost the heading and GPS input to the radar (Seatalk) and would need a NMEA2000 to NMEA0183 gateway to get it back. At this point my radar is old and dumb and probably will stay that way.

Tom

 

[Retriever]

I do, but I don't totally trust it on my new Simrad system yet. I need to test it more...

When operating in fog or at night, I put a VRM/EBL on any target that looks threatening. If the target comes right down the EBL (constant bearing decreasing range, i.e. collision course), I alter course or speed to pass well clear of it.

 

[Moonstruck]

I use MARPA when offshore. Probably wouldn't if I had AIS.

 

[timjet]

I use MARPA to check speed on other boats especially in no wake zones

I have found the speed read out to be very inaccurate even on my new digital radar and heading sensor.

 

[cafesport]

We only use arpa in limited viz situations. Mainly at night with the alarm zones set an hour plus out. We also have ais and use it in combo with Marpa when things get boring.


Via iPhone.

 

[BlueYonder]

AIS (receive only) is enabled by default. Useful information but nuisance warnings when entering a marina. (Do AIS installations require the system to transmit when a boat is docked?). MARPA occasionally, primarlly to answer the question "Geez, how fast is that guy going?"

99% of my boating is day VFR. If I was out at night or in reduced visibility, I would probably use the MARPA function more often.

 

[Moonstruck]

I use MARPA on the Chesapeake Bay to measure the speed of the freighters. They move deceptively fast. When I was on a 7 knot trawler, they could sneak up very fast. Kept just outside the channel.

 

[caltexflanc]

Our Furuno NavNet VX2 does not have ARPA but it does let you keep manual track of the bearing and range to two targets simultaneously. We have used this feature occasionally when boating in fog.

Furuno has a kit, ARP 11, usually sold in a kit with the PGR 500 heading sensor that adapts the 10.4" and Blackbox Vx2 to ARPA.

 

[twistedtree]

I use MARPA to check speed on other boats especially in no wake zones

I have found the speed read out to be very inaccurate even on my new digital radar and heading sensor.

What Radar do you have that gives inaccurate speed readings?

 

[timjet]

What Radar do you have that gives inaccurate speed readings?

I have a Raymarine E90W plotter and a Ray HD digital closed array radar. I was told at the time I installed the above equipment the MARPA function may not be accurate due to an older heading sensor. I had to replace the heading sensor earlier this year with the most current and noticed no improvement in MARPA function. The speed of a target can be off as much as 10 kts and the target heading though more accurate will be off especially if the target is traveling slow.

 

[twistedtree]

I'm one of the people who voted "on a regular basis", but that doesn't mean I track every passing boat. It just means that I regularly find situations where it's useful.

At night is an obvious one. So are low visibility situations like fog.

But I have found many clear visibility situations where I find it very helpful. I've been in plenty of situations where I am on some sort of intersecting path with another boat. Of course if they have AIS that will tell you all you need, but many boats don't have AIS, and lots seem to think all they need is a receiver, but that's another discussion. Anyway, getting a MARPA lock lets you easily sort out how much of a collision course you are on, and monitor the situation through a safe pass.

I have also had situations where I'm working my way through a fleet of fishing boats with gear out running a depth contour. A MARPA lock makes it much easier to see where you are clear and where you need to make a course adjustment to stay clear. Maybe others can judge all this visually at a long distance, but I can't at the sort of distance that I like to keep from other boats. MARPA lets me do that.

Even on the ICW I have found great use for MARPA. I have encountered other boats that I am overtaking or that are overtaking me, and a MARPA lock lets me see how fast they are going. With that, I can figure out where we will pass and be sure it's a safe location, or adjust speed to cause it to be a safe location. I recall one particular case of this on the St Lawrence (not the ICW) where we were being overtaken by a freighter while passing through a particularly narrow and windy section. By knowing it's speed we were able to figure out where the pass would occur and see that we would be past the narrow section in into an open area. It took a lot of stress out of the next 45 minutes.

 

[BDofMSP]

I've only had radar (and MARPA) on charters but I focused on using it immediately. I downloaded the manuals in advance so I'd know how. Really enjoyed learning about it.