Radar Reflectors -- observations and musings

[sailingharry]

So, both of my big boats came to me with a Blipper radar reflector (the big tubular white thing). It's there, I ignore it.


The other day, I was down at the Naval Academy boat yard. There were several of the current (MK2) 44's, with no visible radar reflectors. There was also one of the MK1 44's with a Blipper. Huh?


USNA runs a program with an (over?) emphasis on safety. Certainly they prioritize safety and seaworthiness over performance, and to a certain degree they don't let cost get in the way of safety. They are no bleeding edge win-at-all-cost operation. They also regularly compete in major offshore races and visit foreign countries, so compliance with "rules" is high (I have seen them using motoring and anchoring shapes -- who does that?).


Now, I realize that radar reflectors have universally performed absolutely abysmally on field tests. Even the Blipper, a respected and expensive unit (current version about $250 + installation), has performed poorly. I also know that for vessels with an AIS transponder, any vessel of significant concern (say over 100' LOA) will have been tracking you for miles before radar sees you, so being seen on radar is less important than it once was (I know, there are MANY pleasure boats that don't have transponders, and many that would rather focus on radar than look at an AIS target -- but I'm talking boats with AIS transponders being seen by merchants).


So, inquiring minds want to know. Why would a safety conscious program like USNA not have radar reflectors? Are they not required under the Offshore Special Regulations (ie, racing rules?). Are the USNA boats using some better and less visible technology? Am I missing some obvious (or not so obvious) alternative? Or maybe... the boats that I was looking at were on the hard for maintenance -- maybe they were removed for some reason?


EDIT -- on further digging, I may have answered my own question. The Offshore Special Regulations require either
4.10.1 A passive reflector
or
4.10.2 A Radar Target Enhancer (RTE) which complies with ISO 8729-2:2009 or
equivalent
So, they probably have an enhancer, and I can't see it.

[CaptTom]

I've also seen the poor test results from those "tube" style reflectors.

What I've always used (and which seem to do OK on the tests) are the diamond-shaped metal reflectors that the fishermen use on their high flyers. I figure if it works for them finding their gear, it'll work for me. I actually asked another boater once to check out my radar return. I was the brightest blip in the group, and I was in a low, fiberglass express cruiser at the time.

Per the recommendations, I keep mine in the "catch rain" position. This puts the reflecting facets in position for a horizontal return. On my current boat it's out of sight on the flybridge so you wouldn't see it.

[Kettlewell]

Many years ago I used to ask various vessels how my sailboats looked on radar and I was always showing up well. I think most sailboats with aluminum masts show up fairly well. We should ask those of you have radar onboard what you think?

[hjohnson]

To me, a radar reflector is significantly less important In the age of AIS. I’ve got a transponder on my little Ericson 27, and wouldn’t sail without it. Not only do I show up on their radar screens, they also now know my name, making it much easier to call me on the radio if something needs to be discussed.

Last summer, I was lazily tacking my way down one of the channels in the Canadian Gulf Islands. A deep sea was heading northbound towards one of the anchorages. Instead of blowing their horn at me, or blindly calling for the sailboat in Trincomali Channel, they were instead able to simply call “Sailing Vessel Sagres” and got my attention instantly.

Much safer than relying on a radar return.

But even then, modern X-Band radars should be able to pick up an aluminum mast without much trouble. We were stuck in Vancouver harbour with a bad engine, and as we were talking to Traffic they reported that they could see us both on AIS and radar.

[wholybee]

I carry a reflector, but it is not installed. When I raced in the Pacific Cup (Which is based on US Sailing SER), the rule was that you needed to carry one, but it did not need to be permanently installed. I note in Offshore Special Regulations a radar reflector is listed as required portable equipment. So, the same idea that it doesn't need to be installed may or may not be the case.

I opted not to install it because it would be in the way, and likely catch my sails. My observations are that it is entirely not needed. Perhaps with a 20 year old radar, but anything more modern is plenty capable of seeing a boat. They can see a Panga that is much smaller and doesn't have a huge aluminum mast. Better ones can see a log floating in the water, or a few birds flying in the sky. In every case where I have asked either another sailboat or a larger shipping vessel how I looked on radar, the answer was that I had a very strong return. It isn't just the mast, it is also all the shrouds, the furler foil, winches, your anchor, etc. There is potentially a lot of metal on a fiberglass sailboat.

[Don C L]

My bet is they have the RTE, as you say, since that is so superior to a reflector. Still, those Blippers are supposed to be the best of the passive bunch from what I have read.

[Benz]

I have a Davis sphere-shaped radar reflector mounted at the masthead where it can't be shielded by a sail. Every ship I've talked to has testified that I gave a good return. It's mounted on a solid rod in the "catch rain" position.

[leecea]

On page 112 they list a radar reflector as being on "Mast 1st spreader (Port)"

https://www.usna.edu/Sailing/_files/...2020_FINAL.pdf

[SailingHarmonie]

Originally Posted by Don C L

My bet is they have the RTE, as you say, since that is so superior to a reflector. Still, those Blippers are supposed to be the best of the passive bunch from what I have read.

I am pretty sure that RTE's (like RACONs) don't work at all with modern small boat broadband radar. In the current state of technology, an AIS is multiple orders of magnitude more valuable as a collision avoidance tool than an RTE. But rules are slow to change.

This discussion seems focused on a yes/no question of is a boat is visible to radar, except that is obviously NOT a yes/no question. On my current broadband radar large ships show returns out to 30+ miles. A typical small sailboat does not show a reliable return separate from sea clutter at ranges of more than about 3 miles. A center console fishing boat, needs to be within 2 miles for a reliable return. At shorter ranges, I can see small crap pot buoys. So all of those things are certainly visible to my radar, but all at very different ranges. When I come into an anchorage, I can see every boat there with my radar at a 500 yard range, but that is pretty worthless as a collision avoidance tool when underway.

If I KNOW a boat is there, I can usually manually tune it up out of the clutter at ranges 25% greater than usual, but without a target to tune to, those are the ranges I expect.

[Sailer_Med]

Originally Posted by Kettlewell

Many years ago I used to ask various vessels how my sailboats looked on radar and I was always showing up well. I think most sailboats with aluminum masts show up fairly well. We should ask those of you have radar onboard what you think?

Sailboats show up fine on my radar (Quantum). The regs here require a radar reflector on sailboats also, so I'm not assuming that it doesn't help, although the tests would indicate the tubes everyone has are little use. I "acquire" sailboats as radar targets quite often to see their speed, heading...just for fun

I'm a coastal guy so I'm not usually running my radar much more than 6nm range. The good thing here is that alot of boats have AIS. Having AIS really helped me learn to tune my radar. Like mentioned by another, if you know something is there you can tune to it.

[Don C L]

Yeah, I am less concerned about other sailboats as I am about local fishing boats and ships in the shipping lane!

[deblen]

There are thousands of 64 ft & under commercial fishing vessels from Cape Cod to NFLD that are not equipped with AIS xmit or reception ability. They can't see your AIS transmission.
99% of these fishing vessels have one or two working radars that can pick up a decent radar reflector at several miles,even in the snotty sea conditions common to this area. A plastic boat without a reflector,in the same snotty conditions,may be picked up at roughly 1/2 that distance.
A vessel going 20kts covers 5nm in 15minutes.
An oval aluminum mast is an extremely poor radar reflector.Read up on the principles of radar reflection.
We have fog,wind,rain & darkness up north-it ain't all sunny days & flat ass calm
I have had a Davis alum. reflector on over my backstay for many years-no sail damage,no close calls& I don't care what others think about the look of it
Cheers/Len

[JPA Cate]

The Luneburg Lens radar reflectors work best. With our old radar, we could see our friends who have one at 8 mi, and regular corner reflectors at about 4 mi. We'd see ships at 10 mi. Height helps with distance. Fiberglass boats and timber boats are very poor targets.

All the tools help, especially in fog. Rain, not so much: we've had heavy rain create a signal return blackout.

Ann

[sailingharry]

Originally Posted by deblen

There are thousands of 64 ft & under commercial fishing vessels from Cape Cod to NFLD that are not equipped with AIS xmit or reception ability. They can't see your AIS transmission.

Sadly, you are probably right. AIS receive requires a new VHF radio (under $500) and a 2 conductor wire, and nothing else. Maybe 4 hours for an amateur to install. HUGE return on investment. Those same boats that don't have AIS receive in all likelihood do have a thousand dollar +++ radar, which can barely pick up my plastic boat even with a radar reflector -- assuming they are attentively watching it. There is a good chance that if they are so indifferent about AIS receive, they probably aren't glued to their radar either.

You are probably right. And it blows my mind!

I'm equally dismayed that they don't have AIS transmit, but that is a lot more money, work to install, and all those privacy concerns.

[deblen]

Originally Posted by sailingharry

Sadly, you are probably right. AIS receive requires a new VHF radio (under $500) and a 2 conductor wire, and nothing else. Maybe 4 hours for an amateur to install. HUGE return on investment. Those same boats that don't have AIS receive in all likelihood do have a thousand dollar +++ radar, which can barely pick up my plastic boat even with a radar reflector -- assuming they are attentively watching it. There is a good chance that if they are so indifferent about AIS receive, they probably aren't glued to their radar either.

You are probably right. And it blows my mind!

I'm equally dismayed that they don't have AIS transmit, but that is a lot more money, work to install, and all those privacy concerns.

Yes.It is dismaying.However,that is the way it is at present.
Sort of like COLREGS-All vessels should know & follow the rules-but they don't.