Radar Reflectors -- observations and musings

[Factotum]

Just my own experience with the Firdell Blipper radar reflector. When we crossed the Atlantic Ocean in 1990 from England to Tobago, our boat had a Firdell Blipper. One morning in mid ocean, while drinking coffee in the cockpit, I was surprised to see a large container ship about 1/2 mile off of our stern.

As usual, I grabbed my VHS radio to say Hi and to get a fix. I was using my sextant to navigate because GPS had not yet been released. While speaking with the person on the bridge, the crew lined the bulwarks and we all waved. I was told that they picked us up 50 miles away and changed course just to come by for a look and some diversion. I had a lot of faith in that radar reflector from then on.

Chuck

[Ratty1978]

One time anecdote: We were sailing through a fairly busy commercial shipping channel and it was a bit foggy. I heard a freighter report their position and course on VHF, thought it was close enough that I called them, and they responded that they had us (33 foot fiberglass boat, Al mast, tubular radar reflector at the spreaders) on their radar. This was before recreational AIS receivers were generally available -- which would have helped me see them, but not the reverse.

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?

[CaptTom]

Originally Posted by Ratty1978

... This was before recreational AIS receivers were generally available -- which would have helped me see them, but not the reverse.

... Which is why it's kind of a waste to spend good money on a receive-only AIS. Especially if you're sharing shipping lanes with large commercial vessels.

[st0nes]

Originally Posted by sailingharry

I have seen them using motoring and anchoring shapes -- who does that?

All competent sailors do that.

[Srpulpo]

Originally Posted by 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.

I agree, most big ships should and do use AIS and they are the ones to watch out for including commercial fishing boats. you see each other better then just a dot on the screen. radar is becoming what SSB has become.

[sailingharry]

Originally Posted by st0nes

All competent sailors do that.

I'll be sure to take note of one, if I ever see one. Actually, I've probably seen a few dozen anchor balls over the decades, but I don't think I've ever seen a motoring cone.


But there aren't many competent sailors on the Chesapeake, for sure.

[Icarus]

Originally Posted by 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.

Your alu mast is enough

[ChrisJHC]

Originally Posted by sailingharry

I'll be sure to take note of one, if I ever see one. Actually, I've probably seen a few dozen anchor balls over the decades, but I don't think I've ever seen a motoring cone.


But there aren't many competent sailors on the Chesapeake, for sure.

They are really common around here - whenever there’s an RYA assessor on board!

[Dockhead]

Originally Posted by Srpulpo

. . . radar is becoming what SSB has become.

Disagree completely with this! Radar is primary; it's the ship's eyes. Not everything you need to perceive transmits AIS. Commercial mariners rely primarily on radar and ARPA.


Being visible on radar is important. I think size is key -- all the clever geometry in the world can't create a decent radar cross-section out of a thin tube or tiny ball. We are not always as visible on ships' radars as we think. I'm not sure whether that's a matter of tuning or what; but I often check and despite having the largest Echomax reflector quite high above the water, I am often but not always visible on radar.



If you can't mount one of those larger ones like the Echomax, then I think an active radar target enhancer is a good idea.

[LakeSuperior]

The Tri-Lens reflectors were highest rated 10 years ago. That is considering total radar cross section and off axis performance. I just looked them up and it appears like they are no longer made.

[Lodesman]

Originally Posted by 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.

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.

I agree that AIS is a great tool - but it does have its own limitations. I wouldn't count on it being safer than radar.

Based on your comments, I assume your location is Vancouver, BC - you should be aware of Rule 40 in the Canadian Rules, that requires small non-metallic vessels to have a radar reflector. An octahedral reflector in the "catch rain" orientation gives good (not great) performance - it's an inexpensive added layer of safety, and meets the legal requirements.

Masts don't make very good reflectors, particularly when underway and heeled over - poor angle of incidence. Frequently, radar picks up the engine or other chunks of metal.

[CaptTom]

Originally Posted by Dockhead

...Radar is primary; it's the ship's eyes. Not everything you need to perceive transmits AIS. Commercial mariners rely primarily on radar and ARPA...

Excellent point! Commercial and, especially, commercial fishing vessels aren't always looking out the windows.

The crew of a large, steel ship can afford to rely (more) on their electronics. They don't worry about lobster/crab buoys, driftwood, deadheads or any of the thousand other things which can sink our small, fiberglass boats. Frankly, even a collision with us would be an inconvenience to them, not an existential threat.

For us, our own eyeballs are the primary "eyes" of our vessels. They can be augmented with technology, but none of that absolves us of maintaining an adequate, constant lookout

[SVNeko]

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

Not in my experience. I don't know how many times I've called a ship I see on AIS and warned them that I was in the area, and they were not aware of me. Not that a radar reflector would do any good.

[Kettlewell]

I have been nearly run down several times in poor visibility by tug boats with every navigation aid and presumably someone on watch. Under the conditions and how close they came there is no way we did not appear on radar and yet no sound signal or call was made on the VHF. In both cases what saved us was instant application of throttle and evasive action on the part of the helm on our boat. We came within feet of the tugs. In my experience, small commercial fishing boats are rarely paying attention when on the fish, though they do often respond when either on their way to or from fishing. Just don't expect them to notice you or make any maneuver to avoid you when fishing.

[boatpoker]

Originally Posted by st0nes

All competent sailors do that.

My cruising range for the last 30 years has been between Duluth MN and Antigua. I have seen two other anchor balls and one inverted cone.
I guess that makes five of us