Radar - what to look for

[Dockhead]

Originally Posted by Tayana42

My radar is an old Si-Tex from 1989. Monochrome, takes about 5 minutes to warm up, uses lots of juice, display is at the nav table, not interfaced with anything, shares a screen with the same vintage chart plotter, you have to switch from one to the other. Problem is it still works, nothing wrong with it. Any thoughts on if I should spend the money replacing this old but functional electronics?

No one can answer that but you!!! There is no objective, universal answer to such questions.

You will get a dramatic improvement in radar performance with a modern set. What is sold now is already three or four generations beyond what was available in 1989 (real generations, not Navico's bogus generations). On the other hand, the longer you hold out, the better and cheaper will become what you replace it with. Nothing wrong with holding out if it works, and you're comfortable with it, and you prefer not to spend the money. OTOH, nothing wrong with replacing it if you have the money and crave the advantages of a newer set.

[roland stockham]

Two things nobody else has mentioned which I find critical are stability and independence. Radar is useless unless the picture is effectively stabilized so make sure it is linked to a good electronic compass and has sufficient damping when yawing through a seaway. The second is that independent provides a second means of position fixing to GPS but if it shares the same display as the GPS, ie chart-plotter overlay, you lose a level of redundancy, loose the display and you loose both

[Dockhead]

Originally Posted by roland stockham

Two things nobody else has mentioned which I find critical are stability and independence. Radar is useless unless the picture is effectively stabilized so make sure it is linked to a good electronic compass and has sufficient damping when yawing through a seaway. The second is that independent provides a second means of position fixing to GPS but if it shares the same display as the GPS, ie chart-plotter overlay, you lose a level of redundancy, loose the display and you loose both

I did mention the importance of good quality heading data - it's essential for chart overlay and for usable MARPA. But I would not recommend using radar for position fixing except as a desperate last resort. That's because radar is very accurate for range, but fairly poor for bearing. If the whole GPS system goes down, you'll get a much better position by doing a normal three-point fix with a hand bearing compass. And if the GPS system itself doesn't go down, then you're bound to have multiple backup receivers, don't you? Even most phones these days will give you a GPS (and GLONASS!) position.

[monte]

A question on guard zones setups and how you use them DH and others...
I usually set up a semicircle or larger at maybe 7M and back to our yacht, depending on traffic facing forward. This works well in detecting but when the alarm goes off it continues to go off every 30 seconds the target is in the zone, so I usually alter the bearing to put the target outside the zone. This can work ok but means the full zone isn't guarded till after the ship has passed and I can reposition the zone. Another option I sometimes do is to reduce the outer zone until the ship has passed down to 3 M or less. I guess a donut shape would work but I would be concerned about small yachts and fishing vessels or flotsam that may not show on radar till under 1M away, which is why I like to keep the zone right back to our yacht.
I'd be interested to hear others strategies..

[Dockhead]

Originally Posted by monte

A question on guard zones setups and how you use them DH and others...
I usually set up a semicircle or larger at maybe 7M and back to our yacht, depending on traffic facing forward. This works well in detecting but when the alarm goes off it continues to go off every 30 seconds the target is in the zone, so I usually alter the bearing to put the target outside the zone. This can work ok but means the full zone isn't guarded till after the ship has passed and I can reposition the zone. Another option I sometimes do is to reduce the outer zone until the ship has passed down to 3 M or less. I guess a donut shape would work but I would be concerned about small yachts and fishing vessels or flotsam that may not show on radar till under 1M away, which is why I like to keep the zone right back to our yacht.
I'd be interested to hear others strategies..

Much the same way I use mine. I don't keep the zone right back to the boat, though, because that's where you will get false alarms from clutter. You don't really need the zone to cover right next to the boat, because a target will have to get through the zone to get there anyway.

I tune my guard zones according to what's around, and my system has two zones which you can leave preset to, for example, long range, and close range. The more open and clear the water, the larger the radius of the zone.

I usually use the sector shape, rather than the doughnut, just because this results in fewer false alarm. I admit that this does reduce situational awareness somewhat. But a crucial factor in these alarms being effective is to get down the number of false ones. I tune the sector to be wider or narrower depending on the situation.

One feature which may radar does not have which I really wish it did is the ability to silence the alarm. Best of all -- to acknowledge a target, so that the same target does not keep sounding the alarm, while leaving the zone active with respect to new targets (this could be implemented using the MARPA module). This is one reason why the guard zones quickly become useless when there is much of any traffic. It does help somewhat in more constricted waters to make the zone shallow, so that targets set off an alarm when they enter, but quickly exit the zone and stop setting off the alarm. By this time, you have been made aware of the target, and after that it's up to you to keep track of it.

By the way, for your flotsam and other small targets, you could set up two shallow guard zones -- one a few miles out, and the other close in, but shallow. With FMCW radar, which has better resolution in close, no main bang, and being less subject to clutter, this second guard zone can be quite close if you like. You could, for example, set up a wide but very shallow doughnut as your "perimeter", so that nothing can get into your general location from any direction without your becoming aware of it, and then a close-in sector to give you final warning of anything close off your bow.

[Neptune's Gear]

Agreed Dockhead, you and I use the guard zone pretty much exactly the same way. Mine is normally a doughnut outer at 4-6 miles, inner maybe 1/4 mile. Gives sufficient warning to do something, even for small vessels. Works great!

[poiu]

I have a 2003 Raymarine Pathfinder RL80CRC and I can't get the guard zones to work as well as described here. Actually it is pretty much useless and will miss everything but an oil tanker,which the AIS and the MkI eyeball will have got anyway.

It's great for weather, but those little fishing boats and small yachts - useless, no matter what settings I fiddle with. I wonder if it is normal or if there is a fault to investigate?

Also, are the modern radars good enough to allow a nap whilst solo offshore or will you be woken too often or not enough?

[NSboatman]

Originally Posted by roland stockham

Two things nobody else has mentioned which I find critical are stability and independence. Radar is useless unless the picture is effectively stabilized so make sure it is linked to a good electronic compass and has sufficient damping when yawing through a seaway. The second is that independent provides a second means of position fixing to GPS but if it shares the same display as the GPS, ie chart-plotter overlay, you lose a level of redundancy, loose the display and you loose both

Sorry, disagree completely here re heading indication. Sure, it will be 'more useful' if you have a heading indicator, but radar is FAR from useless without a heading indicator. In fact, I'd bet that 75-80% of the radars out there on s mall commercial boats (fishing boats in particular) right now are NOT linked to compasses. None of the charter boats, fishing boats, pilot launches, sail trainers or small tugs I've worked on had radars tied to a fluxgate compass... And even though the majority of that experience is now 20 years old, I can emphatically state that the radars on those boats were VERY useful anyway!

I do agree on the all your eggs in one basket thing though. Even though I have an MFD that is NMEA 2000 linked to just about everything... and I use it daily... it makes me nervous and I need a backup. I prefer a completely separate, non-networked radar set - even if it's just a wee monochrome LCD like a Furuno 1623 for less than $1500. at least that little beast (which admittedly looks like a toy - but I can attest that it is not) will still be running when the NMEA 2000 backbone breaks... and will allow you to avoid traffic, thread entrances, pick up buoys and get home safely in the fog. That particular model I've worked with a lot on small boats and even in this fog-laden area, it's all ya need really.

[Dockhead]

Originally Posted by poiu

I have a 2003 Raymarine Pathfinder RL80CRC and I can't get the guard zones to work as well as described here. Actually it is pretty much useless and will miss everything but an oil tanker,which the AIS and the MkI eyeball will have got anyway.

It's great for weather, but those little fishing boats and small yachts - useless, no matter what settings I fiddle with. I wonder if it is normal or if there is a fault to investigate?

Also, are the modern radars good enough to allow a nap whilst solo offshore or will you be woken too often or not enough?

Whether you can take a nap and rely on radar guard zones is a hotly disputed topic -- read the earlier posts in this thread. I'm not going to stock my neck out any more on the subject!


My present radar set replaced a Ray RL80CRC+/Pathfinder radar set, the last version of the legendary Pathfinder radar. I sold it for an amazing amount of money, more than half of the cost of the new radar.

My experience was exactly the same as yours -- the guard zones and MARPA practically useless. I replaced the magnetron my last year of using it, and that didn't make a bit of difference. Very low sensitivity to small objects. I think that's normal performance for that set.

I would suggest that you are in a good position to upgrade since your existing set still has value. You will be amazed by the difference.

[Roy M]

I like electronics, a lot. I've installed a fair number of them on other folks' boats over the years. I just traded my entire Raymarine Classic E-120 system to a rigger friend in exchange for his helping me overhaul my old mast and rigging. It is being replaced with B&G Zeus 12" displays, one in the cockpit under the hard dodger, one at the chart table, and a wi-fi tablet in the overhead above my bunk. Did I say I love electronics? For me, there is nothing comparable to being able to determine the position, course, and speed of a target in my vicinity when it's pitch dark and nasty out there. I particularly love overlay radar on the electronic chart, to verify that the radar is seeing the coastline that I see on the display. Then, adding the AIS images to the overlay, gives me confirmation that the target is a vessel, which I can then identify and call on the vhf. Oh, and I also have forward looking sonar, just to add a little piece more of info to the situational awareness. Everything has alarms to assist if I'm grabbing a cup of coffee while alone on watch. I love electronics.

[colemj]

Originally Posted by NSboatman

I do agree on the all your eggs in one basket thing though. Even though I have an MFD that is NMEA 2000 linked to just about everything... and I use it daily... it makes me nervous and I need a backup. I prefer a completely separate, non-networked radar set - even if it's just a wee monochrome LCD like a Furuno 1623 for less than $1500. at least that little beast (which admittedly looks like a toy - but I can attest that it is not) will still be running when the NMEA 2000 backbone breaks... and will allow you to avoid traffic, thread entrances, pick up buoys and get home safely in the fog. That particular model I've worked with a lot on small boats and even in this fog-laden area, it's all ya need really.

If your NMEA2000 backbone "breaks", you will still be able to use your current radar just like the standalone one you are considering adding. All the NMEA data provide are the compass and other inputs - it has nothing to do at all with the radar data to the chartplotter.

I would put a "breakage" in an NMEA2000 backbone WAY down on the list of possible problems.

Unless you regularly get drunk and pull out the sawzall on your boat…

Mark

[Neptune's Gear]

Well, I do use the radar guard zone when singlehanding, along with AIS and Fwd Sonar, all linked to loud alarms, so I can sleep. (Ducking for cover now ) Yes I have been woken by false alarms, but not often. A wooden vessel got to with 3/4 of a mile of me before the radar saw it. Once. Normally, for a ship, both the radar and the AIS alarms will go off, at or near the max range I have set.

All the units in my system work standalone, and just share their data to make things better. However, I only have one display generator - the PC, which mirrors it's display to the cockpit monitor and the laptop. If it fails, I potentially have an issue, so I carry a spare laptop, setup to be a plugin replacement. A cheap and simple system.

I have hit something - there was someone on watch - a mostly submerged large log, at night, that the sonar did not see in the wave clutter - you would never have seen it yourself - and it was my fault because I had tuned the sonar a bit to prevent false alarms in the chop at the time.

Never hit, nor been close to hitting anything when single handing.... Modern Electronics are fantastic, but not a substitute for common sense. Use as you see appropriate, and accept the responsibility for any errors you may make.

[george123]

I have a 42' sailboat and will be mounting a Furuno dome about 20 feet up the mast. I am going back and forth on what size to get DRS2D 19" 2.2KW or DRS4D 24" 4KW. I am not planing to use a dome guard. There was a 17" furuno dome in this location that I will be replacing. The weight is very similar 14.3 vs 16.5 lbs for the 24". Price is only $200 difference.
I am leaning towards the 24" for better performance.

George

[Paul L]

Originally Posted by george123

I have a 42' sailboat and will be mounting a Furuno dome about 20 feet up the mast. I am going back and forth on what size to get DRS2D 19" 2.2KW or DRS4D 24" 4KW. I am not planing to use a dome guard. There was a 17" furuno dome in this location that I will be replacing. The weight is very similar 14.3 vs 16.5 lbs for the 24". Price is only $200 difference.
I am leaning towards the 24" for better performance.

George

I'd strongly favor the DRS4. You get a horizontal beam width of 3.9degs vs 5.2degs. So you have significantly higher resolution -- you can see small targets better, plus more power -- you can see through rain storms better. All for a small percentage increase.

[JPA Cate]

Our radar is completely separate from our chartplotting (which is done on laptops secured belowdecks.) Like most of you, we have many GPS backups, too. What we do not have is radar overlay on the charts. I can see that some of you think that is very useful, others, not so much.

I am totally with NSboatman on not having all your navigational eggs in the one basket: all it takes is one electronics glitch, and you're in a pickle. having separation means that you may not lose it all.

Another thing: placement of the scanner. Ours have always been up the mast, and I like that for the height of eye, and being centered on the boat.

Ann