radar-open or closed?

[markpierce]

Well, Magna, get radar and increase your margin of safety. Personally, I've found radar convenient but have yet seeing it help provide avoidance of hazard. The eyes have.

 

[rslifkin]

The practical difference. So the owner of a turtled trimaran hired me to find and salvage his sailboat 17 miles offshore. It had drifted after his rescue. I have many years of radar experience. That night I had a new 24” radome. I looked for hours with no luck. Later at night, I saw the lights of the Lake Express crossing Lake Michigan. I asked him if he could give me a fix. His huge array spotted the hull which was just 3’ above the surface. He gave me the coordinates 5 miles away and a bearing from my boat to the casualty. Impressive. I did not see it until I was 1/4 mi away. That was one of the very few times I needed more than a 24” radome. Unless you have a huge boat and plan to cruise extensively, a radome should be just fine. The latest generation units are impressive.

In that situation, his radar being mounted higher may have also had a better angle to pick the hulls out of the waves.

 

[psneeld]

If the trimaran was wood or glass with very little metal above the waterline....there is no substitute for power once the beam angles aren't an issue.

 

[rslifkin]

If the trimaran was wood or glass with very little metal above the waterline....there is no substitute for power once the beam angles aren't an issue.

That too. The ship very well could have had radar much stronger than most small-boat sized open arrays.

 

[Codger2]

When i bought my last car i got all the accident avoidance options and i was criticized by some.
I have a friend who does a lot of fishing in the sound and he has had fog roll in and has been a scary situation. He just idles along but has no idea someone is going to hit him.

I agree with your "safety choices." My new Toyota has so many that I won't name them all. The best (IMHO) is the audible & visual warning of traffic (vehicle or human) when backing out. This has saved me at least 8 times in the past year! There are others but at 79 years old, that's a big one! Not to mention blind spot mirrors, adaptive cruise control, etc.

For the boat...a good radar with AIS and the know how to understand and use it! There's no reason in this day & age to not have good instrumentation when in low visibility conditions. Cost? If you can't afford it, stay off the water in those conditions. It's not only for your safety, it's for mine as well!

 

[syjos]

Well the one good thing about an open array:

IT LOOKS SO COOL!!!!

I buy and sell used marine equipment. I sell an unbelievable number of non working radars and satellite domes.

Many buy these non working items because they can't afford to buy a working one and they want to look cool. Or the arch or mast does'nt look right without a radar dome.

One guy had an 18" radar that came with the 50 foot boat he purchased. He thought a 50' boat with the 18" dome looked wimpy so he bought a nonworking 6' array to look more macho. The 6' for show and the 18" for go.
.

 

[syjos]

If you have to look cool .........hmmmmm. ...

Too many barely can dock but that big ole array is still spinning at the dock.....they look cool till the guy in the 35 lobster boat slides it in with 5 inches either side, single, no thruster, wimpy dome. He/she becomes the cool one.

After that no one even notices you have an open array till after dark and everyone reminds you your radar is still on.

I see that all the time.

And I don't say anything, waiting to see if the owner notices and turns the radar off.

Entertainment!

 

[tiltrider1]

Adding radar is adding a safety feature. Upgrading from a 4K 18” dome to a 4K 48” open array only improves the situation in some very narrow niches. In the PNW we use radar for traffic avoidance in the fog were visibility is often less than 1/4 mile. The radar tells you were to look to spot the traffic with your own eyes. If everything out there had AIS we wouldn’t need radar. Reality, almost nothing out there has AIS.

 

[syjos]

If the trimaran was wood or glass with very little metal above the waterline....there is no substitute for power once the beam angles aren't an issue.

Sandpiper is equipped with a 2' 4 kw and a 4' 11 kw open array. Both Furunos.

The 11 kw sees logs and other floating debris in the fog. With calm sea.

The 4 kw does not always see the floating debris.

 

[rsn48]

My now retired buddy - a BC Ferries captain - skippered a number of ships in the fleet. One day he was leaving Horseshoe Bay on the Queen of Oak Bay when he contacted me on my radio to say hi. At that time I owned a 27 Catalina sailboat, somewhat new to me. He was roughly half a mile from me so I thought I'd find out what kind of a radar footprint my boat had.

So I asked him how well my boat showed up on his radar. You can appreciate these ships have decent radar, open array and multiple units. He said he couldn't see my boat on radar at all even though he could visually see me.

 

[tiltrider1]

My now retired buddy - a BC Ferries captain - skippered a number of ships in the fleet. One day he was leaving Horseshoe Bay on the Queen of Oak Bay when he contacted me on my radio to say hi. At that time I owned a 27 Catalina sailboat, somewhat new to me. He was roughly half a mile from me so I thought I'd find out what kind of a radar footprint my boat had.

So I asked him how well my boat showed up on his radar. You can appreciate these ships have decent radar, open array and multiple units. He said he couldn't see my boat on radar at all even though he could visually see me.

That makes no sense. I see kayaks with my radar.

 

[Baker]

I have to say being a ATP airline type rate pilot would hardly ever leave without my it working my issue with most is that I have no tilt control which just drives me up the wall.

While I struggled with your jumbled message, I got the gist of it. As a commercial pilot I too am always trying to find the tilt adjustment....I feel your pain!!!

 

[Baker]

Flying and boating have similarities....but are completely different in some.

Tilt control on marine radar?

5000 hrs and ATP rated USCG helo time and I NEVER have even thought of why I needed tilt on a marine radar if it was mounted correctly for the boat it was on..

It's habit. He wasn't nor am I saying that tilt is needed on marine radars. But if you fly the absolute first thing you do when you turn on a radar is adjust the tilt so you know for sure that the damn thing is working first and foremost. TIlt requirements change as altitude and pitch changes. So wherever the tilt was when the radar was turned off is likely not the tilt that is needed when you turn it on....so it must be adjusted. ANd the first thing one does is point it at the ground to get a gauge of what tilt is needed. I can lik you to a youtube video if you need some schooling.... Obviously radar for airplanes and radar for boats or for two totally different things....one for weather avoidance and the other for collision avoidance. I use radar on the airplane about 100 times more than I use it on the boat. The newest radars on airplanes can do some pretty wild stuff....not to mention an auto mode that I like a lot. But just like any radar anywhere, its use is more art than science.

Oh and BTW, the term for what is referenced in one of the first replies is called "beam width smearing". The narrower the beam, the less this happens and of course the opposite being true.

 

[psneeld]

It is true that many wood and glass boats are difficult to pick up on radar....much of it has to do with how the radar is tuned.

I used radar to search for things on the water throughout a 23 year USCG career with both surface and airborne radar, then a 15 year professional boat captain career and now another 5 years as a retired guy crusing over 2500 miles per year.

Not much has changed....first and foremost is user capability....then power counts most, ....then tuning unless horribly wrong, then mounting unless horribly wrong.....

Sure the gimmicks a radar can do have blossomed dramatically....but the basics remain the same....the biggest change is broadband which I have no experience with.

 

[CarlF]

Big open array antennas stopped looking cool to me after I rode on some of those boats and discovered the captains had no idea how to keep a radar watch. These were also the type who left the marina on a clear day with 50 miles visibility with both radars turning but never looked at the radar screen.

I've cruised foggy Maine for 45 years. Last summer I probably turned the radar on a half dozen times.

When I first got a radar in 1980, it was a miracle. It meant I wouldn't run into an island and could find buoys in the fog. But my first chart plotter made that use unimportant.

Then AIS came along with a much better way to track the North Haven ferry than radar. Now, even most pleasure boats over 50ft are transmitting AIS.

And then Verizon finally put in enough 4G in coastal Maine that I can get a much better real time weather radar map on my phone than my boat radar. Offshore is another matter but I'm not beyond 4G all that often.

I find radar pretty useless for looking for lobster pots - many are barely above the surface. It's easier to pick them out by eye 50ft ahead of the bow than try to make sense of the radar screen.

So now I use my 24" Garmin dome radar for only two things:

1) Coastal - I watch for kayakers and boats without AIS when the fog has reduced visibility to less than 1/2 a mile (it's always set to a 1 mile range). That's plenty of time to avoid them.

2) Offshore at night - set to 6 miles to watch for boats without AIS. Most boats you find offshore at night on the US East coast and Bahamas these days have AIS but there are just enough that don't that the radar is helpful a few times a night.

For both these uses, my 24" dome is more than enough. There's no way I'd spend money on a more expensive radar for these really limited uses. And if I were to buy another radar, I'd probably drop to an 18" dome for less cost and less windage.

 

[MOJO]

Big fan of the Simrad 4G broadband radar. Here's a photo off the back of my boat while anchored at jam packed Block Island over the 4th of July in THICK fog - less than 100' visability. Below the photo are two screen shots from my Simrad radar, one on the 1/8th mile range and one on the 1/4 mile range. I have the radar image offset to the stern to maximize the screen real estate for aft targets. Talk about good horizontal separation, you can see the dinghy behind the sailboat behind me as a separate distinct radar signal... Click on the images to open the up.



1/8th mile range:



1/4 mile range:

 

[stow it]

I think some of you are missing the point, IMO, at what range is your radar the most important? IMO, I don't worry about things that are so far away that they can't hurt me. I'd rather focus on what's in close to the boat or ship. The open arrays lose separation in close, say under one mile.

If I were traveling through a congested waterway and every target had a relative motion vector on it I will only look at or be concerned with the targets within a 3 mile range. I'll worry about a target that is 6 miles or more off later in the watch.

If I'm operating in fog and trying to differentiate between a moving target and a buoy or two moving targets I'm probably zoomed into 1/2 mile range. If my big, open array cannot deliver target separation at those ranges then its worthless in my book.

I am outfitting a new boat and chose the Simrad Halo 24 for the above reasons. It is interesting to note that a well known singing celebrity recently put together a new very fast boat and one would suspect that he could have installed any radar. The captain told me that they chose a dome because it provided superior close in separation to the open arrays.

When I used to work super tankers we only had large open arrays but they were very high up. Properly tuned, I was able to pick up logs, trees and dug out canoes. Sometimes our ARPA display looked like a bowl of spaghetti, which is how I got to zooming in to pick out the critical targets.

Hope that helps.

 

[CaptClay]

Open or closed radar antenna

I had a 2002 18" closed antenna on an olcer Raymarine system on my Mainship when I bought it.. couldn't discern an iron bridge at 1/2 mile. In 2012 I put a new at the time Garmin 18" closed antenna with my new at the time Garmin electronics. At standard factory settings I was able to see a small runabout pulling a water skier behind, clearly separated into two distinct targets 1/2 mile away. That made me a believer! Get newer digital electronics.

 

[alfamike]

oen aray or doam

I feel I can see the difference, & IMHO it is enough that I made the choice for the open array on my boat as my main RADAR.

Go with open array (4 KW is fine for power level) with the biggest antenna - (like 48 inches is good choice) you can fit - mount it as high as you can. - And mount it solidly, as remember the open arrays are 4 times heavier.

Now if your going to have a back up or second radar, which I do on my boat, then maybe a dome would be a good way to go for your second unit. It's light weight allows mounting it higher on your mast, etc.

Good luck.

Alfa Mike

 

[Ski in NC]

A couple of years ago I was on an express where they installed a brand new dome radar. Can't remember the brand, but going down my creek it painted the docks and banks with incredible clarity. I asked him about it and he said it was the new "digital" radar. I was impressed!

My old dome Furuno still works well, but if it poops, I'm going in shopping for the new stuff. Very impressive.

I don't think the new ones it matters much between the open and the dome units. Some boats like mine do not lend themselves to open units. And since the array is only going to be 14' above WL, big power is not going to do much good.

Target discrimination is important up close. At three miles, all you need to know is that there is a target.

 

[twistedtree]

I think some of you are missing the point, IMO, at what range is your radar the most important? IMO, I don't worry about things that are so far away that they can't hurt me. I'd rather focus on what's in close to the boat or ship. The open arrays lose separation in close, say under one mile.

If I were traveling through a congested waterway and every target had a relative motion vector on it I will only look at or be concerned with the targets within a 3 mile range. I'll worry about a target that is 6 miles or more off later in the watch.

If I'm operating in fog and trying to differentiate between a moving target and a buoy or two moving targets I'm probably zoomed into 1/2 mile range. If my big, open array cannot deliver target separation at those ranges then its worthless in my book.

I am outfitting a new boat and chose the Simrad Halo 24 for the above reasons. It is interesting to note that a well known singing celebrity recently put together a new very fast boat and one would suspect that he could have installed any radar. The captain told me that they chose a dome because it provided superior close in separation to the open arrays.

When I used to work super tankers we only had large open arrays but they were very high up. Properly tuned, I was able to pick up logs, trees and dug out canoes. Sometimes our ARPA display looked like a bowl of spaghetti, which is how I got to zooming in to pick out the critical targets.

Hope that helps.

What makes you say that an open array loses target separation at less than a mile? I've not experience that at all.

 

[syjos]

My open array separates close in targets as good if not better than my 24" dome.

Radar performance close up depends on the mounting angle of the array/dome. I have both of mine angled downward so the array is angled slightly down under way to counter bow rise.

 

[w8n4sun]

I really liked the Raymarine Quantum II 18" dome radar on our previous boat. Provided excellent targets and felt safe running in foggy conditions.


On our current boat I elected to go with all Furuno gear (plus NUC pc running Coastal Explorer). The 6' open DRS-NXT takes it to another level with the ability to "see" logs floating on the water.


Most current radar have the option for doplar as well and having the ability to concentrate on only the targets in Red makes it less stressful when running in low visibility with a lot of boats in the area. Red targets are objects closing in at 3kts or better. Green targets are safe as they are either running parallel or away from me.


All new electronics are incredible once you learn how to use them. Good luck with your decision for your new 45.

 

[Nightflyer]

I have to say being a ATP airline type rate pilot would hardly ever leave without my it working my issue with most is that I have no tilt control which just drives me up the wall.

My 2007 Garmin dome radar has tilt but not a separate knob you may be familiar. Not good for finding TRW tops though, more of initial set up.