Radar Reflectors

Advice
#14

A decade or so ago, my local club did a test of various radar reflection strategies (including one commercial reflector on the market at the time) with the local Coast Guard. The other makeshift things we tried were wrapping a paddler in a Mylar blanket, covering a helmet with aluminum foil and one guy actually wore a steel colander on his head. It was on a windy, rough day and the bottom line is that even though they could see us visually, nothing made us visible to radar. According to the radar operator, we never looked any bigger than a sea gull on the water and couldn’t be readily distinguished from the surface noise. If he hadn’t known where we were, he never would have given what he saw a second thought. This was at close range, so at a distance our visibility would have been even worse.

Perhaps if you got a large enough reflector high enough on smooth water, they might be able to see you, but it’s questionable. Additionally, putting anything on a 6’ pole attached to a kayak is a recipe for being capsized by the wind. It’s really a dumb idea and anyone who markets a product like that obviously has no idea what they’re doing, and shouldn’t be trusted.

#15

Ya, but did anyone test an aluminum kayak?

Though the mental picture you painted of a guy with a colander for a hat is pretty good.

#16

Subs hiding under surface ships is a common practice. They can run at higher speeds, their engine noise effecively hidden in the noise interference created by the large marine diesels. It is prossible that the destroyer was tracking, or trying to track, a sub (of either Chinese or Russian signature - though most of china’s sub fleet consists of old russian boats - November class, mostly, IIRC). In this region, only the Chinese subs are of major concern to the US Navy (though tracking all subs is a routine practice, especially for destroyer and submarine crews).

Discipline on container ships may be lax to the point of negligance (it has been in the past and that probably hasn’t changed). Generally, the computer systems use radar and respond to contacts quite effectively. Collisions are rare, and seem to happen only when (usually for dubious reasons) someone overrides the computer system and takes the ship where it has no (legal) business. The computer systems are quite reliable and plot a course that should be maximally efficient. The deck hands are involved with loading and unloading and have little to do while out at sea except to respond to emergencies (fire, someone overboard, etc.). Captains are overly reliant upon the automated systems and, despite their knowledge and skills, spend less and less time on the daily management of the ship and more on crew management. Specialists in radar and ship navigation systems are expensive and are considered redundant to the automated systems. They, generally, are not part of the crew.

The course of the container ship in the first incident was under control of such as system (according to http://www.zerohedge.com/news/2017-06-23/container-ship-was-autopilot-when-it-struck-uss-fitzergerald?page=3). The ship did not report any mechanical problems and did not report the collision until an hour after leaving the point of the accident. In at least one prior incident (APL ship vs. a lowly junk, the APL ship nav system could not be overridden by the captain and crew and APL had to pay massively when the ship left the scene of the incident). in this case, the Nav system seems to have tried to power through the destroyer, backed off, made a course adjustment only to resume it’s normal course after a 15 minute diversion. What the captain and crew were doing, I have no idea. The ship did return (almost) to the point of the collision, but never attempted to render aid and it is probably that it simply was trying to maintain its schedule.

Thus, the fault seems to be on the destroyer crew and since the navy will not report on it’s activites, we can only assume what may have happened. There is a good chance that the ship was carrying on some type of activity where they felt a need to approach the container ship.

Rick

#17

@bnystrom I want to see a photo of the guy with a colander on his head. Or did he make sure they were all destroyed?

#18

Sadly, I don’t think anyone took pictures that day. The weather was pretty miserable and most people other than the kayakers were either inside the station or inside the CG vessel.

#19

@bnystrom said:
A decade or so ago, my local club did a test of various radar reflection strategies (including one commercial reflector on the market at the time) with the local Coast Guard. The other makeshift things we tried were wrapping a paddler in a Mylar blanket, covering a helmet with aluminum foil and one guy actually wore a steel colander on his head. It was on a windy, rough day and the bottom line is that even though they could see us visually, nothing made us visible to radar. According to the radar operator, we never looked any bigger than a sea gull on the water and couldn’t be readily distinguished from the surface noise. If he hadn’t known where we were, he never would have given what he saw a second thought. This was at close range, so at a distance our visibility would have been even worse.

Perhaps if you got a large enough reflector high enough on smooth water, they might be able to see you, but it’s questionable. Additionally, putting anything on a 6’ pole attached to a kayak is a recipe for being capsized by the wind. It’s really a dumb idea and anyone who markets a product like that obviously has no idea what they’re doing, and shouldn’t be trusted.

I think your conclusion is not based on data. The reflector in question weighs much less than a pound, is about 14 inches high, has a round diameter of 2 inches, is meant to be used in foggy conditions when the seas are generally calm (no wind), is hung from thin flexible lightweight driveway marker fiberglass rod and is optimized to reflect x and s band marine radar…about 9 square feet of metal higher above the water than a nonreflective plastic sheet.

However, as soon as I get a chance I will ask for and share results from a recreational craft or government boat.

#20

Anyone use a Luneberg Lensatic radar reflector?
For my long distance friend Reinhardt Zollitsch it seems to work

#21

@rjd9999 said:
Subs hiding under surface ships is a common practice. They can run at higher speeds, their engine noise effecively hidden in the noise interference created by the large marine diesels. It is prossible that the destroyer was tracking, or trying to track, a sub (of either Chinese or Russian signature - though most of china’s sub fleet consists of old russian boats - November class, mostly, IIRC). In this region, only the Chinese subs are of major concern to the US Navy (though tracking all subs is a routine practice, especially for destroyer and submarine crews).

Discipline on container ships may be lax to the point of negligance (it has been in the past and that probably hasn’t changed). Generally, the computer systems use radar and respond to contacts quite effectively. Collisions are rare, and seem to happen only when (usually for dubious reasons) someone overrides the computer system and takes the ship where it has no (legal) business. The computer systems are quite reliable and plot a course that should be maximally efficient. The deck hands are involved with loading and unloading and have little to do while out at sea except to respond to emergencies (fire, someone overboard, etc.). Captains are overly reliant upon the automated systems and, despite their knowledge and skills, spend less and less time on the daily management of the ship and more on crew management. Specialists in radar and ship navigation systems are expensive and are considered redundant to the automated systems. They, generally, are not part of the crew.

The course of the container ship in the first incident was under control of such as system (according to http://www.zerohedge.com/news/2017-06-23/container-ship-was-autopilot-when-it-struck-uss-fitzergerald?page=3). The ship did not report any mechanical problems and did not report the collision until an hour after leaving the point of the accident. In at least one prior incident (APL ship vs. a lowly junk, the APL ship nav system could not be overridden by the captain and crew and APL had to pay massively when the ship left the scene of the incident). in this case, the Nav system seems to have tried to power through the destroyer, backed off, made a course adjustment only to resume it’s normal course after a 15 minute diversion. What the captain and crew were doing, I have no idea. The ship did return (almost) to the point of the collision, but never attempted to render aid and it is probably that it simply was trying to maintain its schedule.

Thus, the fault seems to be on the destroyer crew and since the navy will not report on it’s activites, we can only assume what may have happened. There is a good chance that the ship was carrying on some type of activity where they felt a need to approach the container ship.

Rick

Two destroyer radars were turned off? The radars of tanker/cargo ships, carrying millions of dollars of goods, were turned off ? No one was on watch in two destroyers outfitted with thermal imaging gear, AiS receivers, electromagnetic emission suites??? No one was on watch on the tanker/cargo ships? The tanker which returned to a suspected collision event went to a geographical location rather than to a radar blip?

Or, the destroyers were cruising within 100 feet of the ships, in their radar shadows.

I may be wrong about subs under the tankers…perhaps the destroyers were using the ships to hide their own acoustic emissions and to become indistinguishable on radar.

#22

@kayakmedic
Thanks for the name! It was Reinhardt that Jim and I ran into at Thief Island some years ago. He had just rounded Pemaquid in what he said would be his last transit of the full Maine Island Trail. In the Sea Wind, his Kruger boat, that is pictured in the article. He was staying on Thief for a night before heading for Penn Bay.

Neat guy. Anyway, he also mentioned that he had done tests on various radar reflectors for kayaks relatively recently, maybe in the last couple of years then.

If he found something that worked for his purposes, I would pay attention. Here is a link for anyone who wants to read about his trips.
http://www.zollitschcanoeadventures.com/

#23

Two destroyer radars were turned off? The radars of tanker/cargo ships, carrying millions of dollars of goods, were turned off ? No one was on watch in two destroyers outfitted with thermal imaging gear, AiS receivers, electromagnetic emission suites??? No one was on watch on the tanker/cargo ships? The tanker which returned to a suspected collision event went to a geographical location rather than to a radar blip?

I did not say that the distroyer radars were off. I did say that the destroyer(s) were at fault for the collisions. For some reason, they approached these ships for whatever reason and bungled badly. Why they approached these ships at all is, at best, a guess, though certainly someone in the navy knows.

And it is likely that nobody was on watch on the cargo ships. Most of the time, the bridge of these ships are manned in high traffic areas, but not always. As I said, it is common to let the automated systems do their job when ships are fully out at sea. I know of at least one instance (the APL collision with the junk) where the captain was unable to override the nav system to render aid (the bridge was unoccupied and he was wakened by a collision warning system that sounded in his wardroom. Once on the bridge, he was unable to obtain control of the ship and render aid).

So yes, the tanker returned to a geographical location, not to perform a rescue or respond to the collision, but to return to its planned course several miles away from the point of contact. This suggests (not proves) that the bridge was not manned.

Or, the destroyers were cruising within 100 feet of the ships, in their radar shadows.

Possibly, but there is little benefit to be had from same unless there was some wargaming going on.

I may be wrong about subs under the tankers…perhaps the destroyers were using the ships to hide their own acoustic emissions and to become indistinguishable on radar.

Again, possibly, though the why would be nice to know. That they were struck amidships shows a marked lack of situational awareness that should not be possible by a system as elaborate and reliable as is installed on this ships. Clearly, there is something going on that won’t be admitted until a lot of time has passed.

Rick

#24

Celia. Willow leaf is not on this thread
Shiraz. I take it you have never worked a lobster boat. Especially when there is no stern man they are always on autopilot when returning to the co op

#25

@kayakmedic
Sorry!! Thanks to you for the name. I just couldn’t quite remember it.
I had just responded to willowleaf in another thread. I fixed it above a d named you. Dangers of doing my internet work sitting in the front seat of a car so I am within range of Wifi. They can’t get it down thru the trees to where I stay.

#26

@kayamedic said:
Anyone use a Luneberg Lensatic radar reflector?
For my long distance friend Reinhardt Zollitsch it seems to work

No but supposedly the company makes premium stuff…products are used on F22/F35 stealth aircraft when training to prevent collisions when flying with commercial traffic.

#27

@Barge said:
I think your conclusion is not based on data. The reflector in question weighs much less than a pound, is about 14 inches high, has a round diameter of 2 inches, is meant to be used in foggy conditions when the seas are generally calm (no wind), is hung from thin flexible lightweight driveway marker fiberglass rod and is optimized to reflect x and s band marine radar…about 9 square feet of metal higher above the water than a nonreflective plastic sheet.

However, as soon as I get a chance I will ask for and share results from a recreational craft or government boat.

How about posting a link to the product you’re talking about?

Speaking of data, how do you get “about 9 square feet of metal” from a 14" x 2" tube? There’s no way that math works.

“Meant to be used in calm conditions”? Assuming it’s mounted on the aft deck, exactly how are you going to remove and stow it when the wind picks up?

Something of that size flying 6’ above the deck can easily torque the boat enough to cause control problems or a capsize in any significant wind. Fiberglass poles are only “flexible” to a point. If it’s flexible enough not to cause handling issues, it’s never going to stay upright.

This is not a new idea; this same kind of product was marketed over a decade ago and failed because it didn’t work.

BTW, Mylar Space blankets **are **radar reflective.

#28

@Celia said:
@kayakmedic
Sorry!! Thanks to you for the name. I just couldn’t quite remember it.
I had just responded to willowleaf in another thread. I fixed it above a d named you. Dangers of doing my internet work sitting in the front seat of a car so I am within range of Wifi. They can’t get it down thru the trees to where I stay.

I can relate. I’ve been using my phone for two months. I’m tired of peering at a tiny screen.

#29

@bnystrom said:

@Barge said:
I think your conclusion is not based on data. The reflector in question weighs much less than a pound, is about 14 inches high, has a round diameter of 2 inches, is meant to be used in foggy conditions when the seas are generally calm (no wind), is hung from thin flexible lightweight driveway marker fiberglass rod and is optimized to reflect x and s band marine radar…about 9 square feet of metal higher above the water than a nonreflective plastic sheet.

However, as soon as I get a chance I will ask for and share results from a recreational craft or government boat.

How about posting a link to the product you’re talking about?

Speaking of data, how do you get “about 9 square feet of metal” from a 14" x 2" tube? There’s no way that math works.

“Meant to be used in calm conditions”? Assuming it’s mounted on the aft deck, exactly how are you going to remove and stow it when the wind picks up?

Something of that size flying 6’ above the deck can easily torque the boat enough to cause control problems or a capsize in any significant wind. Fiberglass poles are only “flexible” to a point. If it’s flexible enough not to cause handling issues, it’s never going to stay upright.

This is not a new idea; this same kind of product was marketed over a decade ago and failed because it didn’t work.

BTW, Mylar Space blankets **are **radar reflective.

I already a posted a link. Look up. I think you should look at it.

Also don’t confuse reflective area with physical area.

#30

Again, it’s nothing new and the “max reflective area” is deceptive, as it’s only the area facing the radar that has any effect. While I don’t doubt that this is helpful when rigged high on a sailboat, it’s not going to do much for a kayak unless you’re willing to compromise your ability to control your boat, plain and simple.

Do whatever you like, but if you think this is going to make you safer, you’re kidding yourself. IMO, having full control over your boat is far more important than any minor radar visibility you may gain.

#31

@bnystrom said:
Again, it’s nothing new and the “max reflective area” is deceptive, as it’s only the area facing the radar that has any effect. While I don’t doubt that this is helpful when rigged high on a sailboat, it’s not going to do much for a kayak unless you’re willing to compromise your ability to control your boat, plain and simple.

Do whatever you like, but if you think this is going to make you safer, you’re kidding yourself. IMO, having full control over your boat is far more important than any minor radar visibility you may gain.

I don’t get your point at all given the discussion of close calls with lobster boats and the unwelcome sound of a motor approaching in the fog or the use of autopilot radar. I would gladly compromise some changes in handling in order to avoid becoming lobster food. Even if there was a change, at least you could hold the pole up when a boat is approaching and no one is in the pilot house.

The reflector in question is symmetrical (its round) and is comparable to 9 sq feet of flat metal struck by a radar from any direction. It uses a physical phenomena called resonance to increase the reflected power to the same value that a non-resonating 9sq feet metal plate would reflect.

Reflective area is a useful metric for comparing two or more reflectors as they can become very large or small.

#32

My experience with Maine lobstermen is that the only way you’re going to be safe is to get as far away from them as possible and/or paddle water that they can’t navigate. That often means hugging the shoreline and making open water crossings as fast as possible. As far as getting them to avoid you, an airhorn is likely to be more effective than a radar reflector, as from what I’ve seen, they are so focused on their task at hand that the only things in the cockpit that they notice are the throttle and steering wheel.

As for holding up the pole, are you serious? You’re willing to be a “sitting duck” and rely on the hope that they’re actually using their radar? No thanks, I’d rather have both hands on my paddle so I can get the heck out of the way if necessary. I understand how unnerving it is to have a lobster boat in your vicinity in the fog (been there several times), but I’m far more concerned about my ability to move quickly and control my boat than with gimmicks that might make me more visible to a lobsterman who might be using his radar.

Do whatever you think it best and good luck to you.

#33

@Barge
I doubt that anyone can understand the issues of ducking the lobster boats (or ground fishing boats where there is still a fleet) on autopilot in Maine without a few near misses. There are just too many variables that people from lower down will not expect. I have run into just about all of them, including these errors from highly qualified coaches from lower states. Some of them -

Right on red to figure out where the boat channel is. Nope, this one only works on one side of the many little harbors along that coast. On the western side it’ll have you in the middle to get run down.

Working boats staying within marked channels. Not always - with a tide range at 12 feet by midcoast and higher as you go further east, a boat coming in at high tide can be outside of the usual channels because there is plenty of water for their draft at that tide state. Local fishermen may take advantage of that, in fact that is often where some of their pots need to be retrieved from. Kayakers need to heed proximity to rocks, not where the channel is marked on the chart for a lower tide state…

Assumption that they can hear - not always. Years of diesel engines tend to have reduced the hearing of many, more so by simultaneously playing country and western music very loud to be heard over the engines. (Makes a heck of a wake up call when you are camped on an island.) The ones who want to protect their hearing wear headsets, so those guys can’t hear any better than the ones who are partially deaf.

I am not saying a radar unit would never work, but I am with bnystrom on relying on something like that. Your best bet is to stay the heck out of their way, and that is not always easy. Even after 17 years of paddling Muscongus and knowing the bay without a chart (though I still carry one), I still have at least one moment a year where it is unclear that I have chosen the correct path. That is why I prefer paddling Muscongus to the bay on either side, I have a whole lot less working boat traffic to avoid than in Casco or Penn Bay.