# Do I need a radar reflector?



## Patbarbeau (Jul 25, 2008)

I plan to sail my new boat on the St-Lawrence river where cargos are frequently present. I am installing a radar reflector but was wondering why the aluminium mast does not reflect radar itself? I am just curious to understand the difference especially since my reflector seems to also be made of aluminium??? Thanks for any source of info.


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## camaraderie (May 22, 2002)

Thin Profile and rounding of mast tends not to show up WELL. Lots of different facets on reflector do a better job at reflecting radar waves back to the sender.


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## SteveInMD (May 11, 2007)

I read an article where they tested radar reflectors. Many performed very poorly. There are active ones that listen for a signal and shoot a beam back with a transmitter. They are very effective. The amount of fog, night time sailing, and proximity to commercial traffic would help decide if the cost is worth it.


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## paulk (Jun 2, 2000)

US Sailing and the RORC have both performed tests on radar reflectors. Both sets of tests seem to indicate that the Davis type, (round interlocking panels that create "pockets") mounted in a "catch rain" position is among the most effective passive reflectors available. It's also one of the less expensive. Actual results can vary because of the way the reflector is mounted, the angle of heel of the boat, the height of waves, and a lot of other technical stuff. We used ours last week in Buzzards Bay with about 200' of visibility, and were glad to have it deployed.


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## Maine Sail (Jan 6, 2003)

*Speaking as someone..*

Speaking as someone from the foggy state of Maine all I can say is YES!

Radar likes right angles and flat surfaces to reflect signal back. Rounded masts are not a good reflector. While many boats do show up without a reflector the target definition and target itself on screen is usually quite small and can be mistaken for a lobster pot or buoy or sea clutter. Make your boat show up on someones radar screen and definitely buy a reflector..

Oh never mind I'll just show you. I took this photo a few weeks ago at my mooring during the set up and install of my new Garmin HD radar that replaced a Raytheon CRT unit.

The target labeled in red as "C-30" is a Catalina 30 with no radar reflector. The much bigger target labeled in green as "M-28" is a Morris 28 with a radar reflector. Hopefully seeing is believing...!

LOOK BIG!!


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## max-on (Mar 30, 2004)

I bought one today; SD convinced me when he was on my boat a few weeks ago, and he also gave me some tips on mounting the reflector gained from his experience. Thanks again Dawg!










You know, I still have not read SD's post linked in his signature that he keeps telling everyone to read. 

Edit: Hal, that radar screen looks sweet; it puts my 1997 model to shame. I guess I will add HD radar to the list!


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## Maine Sail (Jan 6, 2003)

max-on said:


> Edit: Hal, that radar screen looks sweet; it puts my 1997 model to shame. I guess I will add HD radar to the list!


And that was "out of the box" auto settings! I had not even begun to tweak or play with the settings! I really do like it but the Garmin instructions for radar are NON-EXISTENT!! Not kidding they don't have ANY!!!

If you buy a Garmin you better already know how to operate a radar and what the lingo means cause they won't tell ya.....


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## jrd22 (Nov 14, 2000)

I am definitely of the belief that you want to do everything that you can to make yourself visible to the big guys. Even if a reflector didn't do much, I would feel better having it up there. I am hoping to do a test on my boat from another boat with a CRT, with and without reflector at different ranges. I know from running my radar that different boats give vastly different returns, but the best are from the bouys that have the chambers like the Davis (we call them Cormorant motels).

Hal- I noticed that in your screen shot you don't have a "cone" at your location, are you mast mounted or pole? Excellent picture, how do you like color radar for night use, is there a different palette like on a plotter?

John


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## chuck5499 (Aug 31, 2003)

i put two up above my top spreader - they are round and attache to the stays - one on each side 

had an interesting example on why 2 - recently was coming north in the ocean and another sailboat was following me - we both had our sails up and as he went from my starboard to hard off my port as he went more towards land i lost his footprint on my radar at times - we had talked on radio a bit and i asked if he had 1 or 2 reflectors as as long as i could see the reflector my radar could track it but when his sail covered it - it was a spotty reception and at times i would lose his track all together - i tired using marpa but it would at times tell me no signal - 2 reflectors up high take care of that problem as well as the heeling problem 
just my opinion 
chuck and svsoulmates 
ki4sry 
on the hook cambridge md


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## artbyjody (Jan 4, 2008)

*A Caution*

Radar deflectors in my opinion are one more of those aux gears you can have to make safe voyage passages (and yes I have on on my Barberis). However, nothing accounts more on a boat than standing proper visual watches - anywhere you transit. Odds are on a sailboat under sail - you are the one that needs to get out of the way - not the other way around.


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## sailingdog (Mar 19, 2006)

Max-on's radar unit is an old CRT unit from about WWII.  

Right angles, corners, and hard edges are what you want to maximize radar returns. 

One of my friends, who worked at Aberdeen, once told me that a B52 bomber, although much larger than an 1980s F150 pickup truck, has a far lower radar signature, since the truck is all right angles and flat surfaces with hard edges... 

BTW, getting one larger radar reflector is better than getting two smaller ones, since the smaller ones used together can often partially cancel each other out from what I understand.


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## Maine Sail (Jan 6, 2003)

artbyjody said:


> However, nothing accounts more on a boat than standing proper visual watches - anywhere you transit. Odds are on a sailboat under sail - you are the one that needs to get out of the way - not the other way around.


Unless you sail in this stuff often then your ears and senses become as important as your eyes..


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## Cruisingdad (Jul 21, 2006)

halekai36 said:


> Speaking as someone from the foggy state of Maine all I can say is YES!
> 
> Radar likes right angles and flat surfaces to reflect signal back. Rounded masts are not a good reflector. While many boats do show up without a reflector the target definition and target itself on screen is usually quite small and can be mistaken for a lobster pot or buoy or sea clutter. Make your boat show up on someones radar screen and definitely buy a reflector..
> 
> ...


A good post.

- CD


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## max-on (Mar 30, 2004)

sailingdog said:


> Max-on's radar unit is an old CRT unit from about WWII.


Very funny . . .


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## Vitesse473 (Mar 16, 2008)

Here's an interesting study done on radar reflectors. Basically confirms that the age old Davis octahedral style is the best (and the cheapest). I will be adding this and AIS very soon.

1995 Radar Reflector Test


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## camaraderie (May 22, 2002)

Hal...great screen shot from your new Garmin! Thanks.


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## sailingdog (Mar 19, 2006)

max-on said:


> Very funny . . .


ROFLMAO... I was wondering when you were going to spot that....


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## capttb (Dec 13, 2003)

Had a huge whalewatching boat on my transom once when we hit a "wall" of zero visibility, he reported that my cheap Davis reflector was working well and he'd give me a little more room as I'd requested. I could hear him getting closer to the point I couldn't hear anything ahead so I'd radio'd to make sure my "Tinfoil Hat" was working and ask him to back off. Without radar sometimes you have to keep watch with your ears.


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## craigtoo (Aug 17, 2007)

in a pinch....is it possible to hoist a mesh laundry bag full of crushed coke cans... Sort of a poor mans reflector...of course beer cans would work as well..???


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## arf145 (Jul 25, 2007)

I was going to mention the possibility of a tin foil hat as kind of a poor crazy man's reflector, but this seems like a serious discussion


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## Freesail99 (Feb 13, 2006)

> I was going to mention the possibility of a tin foil hat as kind of a poor crazy man's reflector, but this seems like a serious discussion


Practical sailor did test tin or aluminum foil and it really didn't work.


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## sailingdog (Mar 19, 2006)

Free's also tested his hat....  

No, the problem with cans and foil is that they don't have large flat surface areas of sufficient density. They also don't really have the sharp angular corners and edges that a Davis Echomaster does.


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## artbyjody (Jan 4, 2008)

arf145 said:


> I was going to mention the possibility of a tin foil hat as kind of a poor crazy man's reflector, but this seems like a serious discussion


Just have as many grills as you can on the stern  no need for tin foil hats then!


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## arf145 (Jul 25, 2007)

artbyjody said:


> Just have as many grills as you can on the stern  no need for tin foil hats then!


Yes, but do grills also serve to deflect thought control waves?


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## Cruisingdad (Jul 21, 2006)

First time I met Cam, he had one of those tin foil hats on. I asked him why he was wearing it. I assumed it was a radar reflector. But no! Cam said, "Aliens from Outer Space, CD. They been wanting to sexually assault me. The hat keeps them away."

Weird, I thought. Probably keeps the women away too.

Then I saw him a week later. He was not wearing his hat. I asked him why. He said, "Didn't work."

Eeewwww! Freaky!

Here he is before the abduction:










- CD

PS I guess this thread has now officially gone off topic???


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## Cruisingdad (Jul 21, 2006)

Luckily, he did protect his cat too. Poor ole kitty.


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## sailingdog (Mar 19, 2006)

CD-

at least the OP got a good answer before the thread derailed.


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## camaraderie (May 22, 2002)

I wear that hat whenever I'm near CD's boat. Did you see Halekai's scope shot of the floating Barbeque???


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## Patbarbeau (Jul 25, 2008)

Well... thanks for everyone's reply and info.... and everything else. That was more than exepcted! Camaraderie, I like your screen shot!


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## sailingdog (Mar 19, 2006)

Cam-

Wouldn't that be Grills with attached C400??? The big stone and brick BBQ Pit probably helps a lot with the radar return.


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## capttb (Dec 13, 2003)

Come on Dad, Let's say it together "Ya'll can just bite me!"


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## Bene505 (Jul 31, 2008)

I'd like to thank Chuck for the 2-reflectors story. I just bought a Beneteau 505 that came with the last small "piece" of a radar reflector still attached. I will definitely be replacing it with 2 reflectors. (Not sure how I'll get them above my top spreader, it HIGH up there!)


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## Boasun (Feb 10, 2007)

max-on said:


> I bought one today; SD convinced me when he was on my boat a few weeks ago, and he also gave me some tips on mounting the reflector gained from his experience. Thanks again Dawg!
> 
> 
> 
> ...


This isn't the most effective way to hang it. You should have it in the rain catcher mode for the best reflections. This means making a three leg sling for it, plus a three leg sling at the bottom to stablize it.


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## christyleigh (Dec 17, 2001)

Boasun said:


> This isn't the most effective way to hang it. You should have it in the rain catcher mode for the best reflections. This means making a three leg sling for it, plus a three leg sling at the bottom to stablize it.


 I think that 2 dimensional picture may be misleading. If in the picture it is in fact hung from a fin, then yes it is wrong. The one I bought 5 or 6 years ago came with the mounting hardware that attached in the center/apex or what ever the place where all the fins meet in the middle is called with an eye on the top and bottom so it only needs 1 line top and bottom to keep it in the "rain catcher" orientation (which means if all the joints were sealed the top 3 dimensional triangle would fill with water). I think that is what the picture actually shows but the attachment may be blurred into looking like it attaches to the fin which IS wrong.


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## sailingdog (Mar 19, 2006)

Boasun-

The photo is of the deluxe echomaster and it is hanging from a piece that passes through the core. It is in the rain catcher position, but doesn't require a three point sling, since the mounting system takes care of that and allows you to use a single line passing through the center. If you look closely, you'll see the line is actually attached to a bail that is passing through the center of the radar reflector.


Boasun said:


> This isn't the most effective way to hang it. You should have it in the rain catcher mode for the best reflections. This means making a three leg sling for it, plus a three leg sling at the bottom to stablize it.


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## rikhall (Feb 7, 2008)

Greetings

We are recreational sailors. We sail in New Brunswick, Canada and the coast of Maine. We see LOTS of fog. (We also have beautiful clear blue hot days - so don't be afraid of this area)

Radar reflectors, unless they are very good ones, can give you a very scary sense of protection. An excellent paper of the usefulness of reflectors can be found here:

http://www.ybw.com/pbo/pdfs/radar_reflectors.pdf

We have just upgraded to an Irwin Citation 34, but our 28 foot Tanzer had radar, radar reflectors, GPS, chart plotter and AIS. We don't like surprises. I want to know what is out there and who they are.

Never assume the radar reflector will keep you safe. Relying on a reflector assumes:


the other guy has radar
the other guy has his radar turned on
the other guy is looking at his radar
your reflector is giving his radar a target

Pretty big assumptions!

Be aware, keep proper lookouts and stay out of the big guys way!


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## Maine Sail (Jan 6, 2003)

*Yep...*



rikhall said:


> Greetings
> 
> We are recreational sailors. We sail in New Brunswick, Canada and the coast of Maine. We see LOTS of fog.


Yep!!!!!



rikhall said:


> Never assume the radar reflector will keep you safe. Relying on a reflector assumes:
> the other guy has radar


Even in Maine it's less than 50%!!!!!



rikhall said:


> 2. the other guy has his radar turned on.


Now we're down to 25% with radar..!!



rikhall said:


> 3. the other guy is looking at his radar


Crap now we're down to 15% and half of those can't see the targets cause the display is 10 feet away in the cabin and their glasses are steamed up!



rikhall said:


> 4. your reflector is giving his radar a target.


Your odds of this are much higher than the others!! I've yet to see a boat with a reflector, even a crappy one or "lesser performing one", give worse returns than a boat with none...

Considering I usually put in lots and lots of hours per season in thick fog this is what I feel really helps.

Display at the helm
Radar overlay
Automated fog horn
Nose, ears eyes and polarized glasses
VHF turned ON

Last weekend; rain fog and 8 knots on the nose welcome to Maine:


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## sailingdog (Mar 19, 2006)

Halekai-

The fog looks a bit thin in that photo.


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## Maine Sail (Jan 6, 2003)

sailingdog said:


> Halekai-
> 
> The fog looks a bit thin in that photo.


Yes, that is thin for up here! It was about 50-75 yard vis & sometimes it's hard to see the bow clearly.....


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## mrwuffles (Sep 9, 2008)

halekai36 said:


> Yes, that is thin for up here! It was about 50-75 yard vis & sometimes it's hard to see the bow clearly.....


you obviously have to look harder......


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## timebandit (Sep 18, 2002)

Where is the best mounting position?

Fwd, aft, port or stbd??

Rick


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## sailingdog (Mar 19, 2006)

On a halyard going up to the spreaders is probably best.


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## GaryHLucas (Mar 24, 2008)

Radar reflectors work, not because they are flat, but because they have internal corner cubes. A flat surface reflects a beam off at an angle exactly the same as it came in. In other words, it is nearly impossible the get a reflection back from a flat surface! Hence all the FLAT surfaces on stealth aircraft and ships. A round mast reflects better than a flat surface because a there is a line on the surface somewheres that is exactly perpendicular to the radar beam, and that is what the radar sees.

A corner cube reflector has a unique property. A beam going in gets reflected two or three times and comes out exactly parallel to the direction it went in! So virtually the entire beam goes right back to the radar that sent it. If the radar beam is exactly perpendicular to any face, then it won't work well. If it is bent up and the angles are not exactly 90 degrees it also won't work well.

Those bright reflectors your headlights hit along the road? those are corner cube reflectors too.


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## GaryHLucas (Mar 24, 2008)

Patbarbeau said:


> I plan to sail my new boat on the St-Lawrence river where cargos are frequently present. I am installing a radar reflector but was wondering why the aluminium mast does not reflect radar itself? I am just curious to understand the difference especially since my reflector seems to also be made of aluminium??? Thanks for any source of info.


Have you consider AIS? I made a trip across the eight lanes of ship traffic in and out of New York Harbor on a boat with AIS. It is amazing to be able to see every ship within 15 miles shown right on your chartplotter, and get all kinds of data about exactly what the ship is doing.


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## sailingdog (Mar 19, 2006)

Not such a good idea IMHO, since you might be able to see them, but they'll have no idea you're even out there, and if you have a problem and end up in the path of one of the big container carriers, all AIS will do is show you how you're about to die.... granted, you might be able to contact them on the VHF... but it would help them more if they could see you.

BTW, not all chartplotters have the ability to take in AIS data. Only fairly recent ones will show AIS data on the screen. Same thing with DSC data, not all will show the plot of a ship issuing a DSC call. The chartplotter has to have the software capabilities to do either.



GaryHLucas said:


> Have you consider AIS? I made a trip across the eight lanes of ship traffic in and out of New York Harbor on a boat with AIS. It is amazing to be able to see every ship within 15 miles shown right on your chartplotter, and get all kinds of data about exactly what the ship is doing.


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## GaryHLucas (Mar 24, 2008)

sailingdog said:


> Not such a good idea IMHO, since you might be able to see them, but they'll have no idea you're even out there, and if you have a problem and end up in the path of one of the big container carriers, all AIS will do is show you how you're about to die.... granted, you might be able to contact them on the VHF... but it would help them more if they could see you.
> 
> BTW, not all chartplotters have the ability to take in AIS data. Only fairly recent ones will show AIS data on the screen. Same thing with DSC data, not all will show the plot of a ship issuing a DSC call. The chartplotter has to have the software capabilities to do either.


So you trust a guy on a big ship to be watching the radar for a tiny little blip that is you, in a field of large blips from ships that could sink him? You trust a guy that won't even know he sunk you, more than you trust getting out of his way MILES before he gets to you? You sir are a braver man than me!


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## sailingdog (Mar 19, 2006)

No, I just don't think AIS by itself is a good solution. You need to know where they are, but they also need to know where you are. Sometimes, you'll have a problem that prevents you from getting out of their way...and if they can't see you, you're screwed.



GaryHLucas said:


> So you trust a guy on a big ship to be watching the radar for a tiny little blip that is you, in a field of large blips from ships that could sink him? You trust a guy that won't even know he sunk you, more than you trust getting out of his way MILES before he gets to you? You sir are a braver man than me!


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## dugout (Nov 3, 2007)

*Radar reflectors*

The locals here mark narrow channels with 1"PVC pipes and the tops of the pipe are wrapped with the silver reflective tape, the type used down the side of tractor trailers. Yes it's designed to reflect light, and it does, but these channels show up like lighted runways on radar. I took some and applied it to a local day marker which has always been a poor radar target but not any more.
I added a few pieces to the mast vertically and wrapped horizontally, near the spreaders. One would need to look for it to see it, even from the dock. The difference in the radar signature is dramatic! Radars love this tape. 
Put some on something and take a look with your radar at the before and after. I am sure you will be impressed. Even adding some to the flat surfaces of the Davis would probably make a good thing even better.


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## sailingdog (Mar 19, 2006)

dugout-

do you have a link to the tape in question??


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## Maine Sail (Jan 6, 2003)

*It's..*

It's most likely due to the 3D nature of the reflective dots that make up the tape. The 3 dimension crystals of say Solas approved tape give much more light reflection, can't comment on radar, than does a 2D reflector tape and it's my guess that this tape uses 3D crystal reflection technology and it may be bouncing back some radar signal? It seem like a stretch but.......

I have Solas tape on my radar pole, a little hard to see in the day time, and I also have it on my mast. It's great for a potential night time rescue and also for seeing the boat in a crowded anchorage with a headlamp late at night. That stuff REFLECTS!!!!


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## GaryHLucas (Mar 24, 2008)

dugout said:


> The locals here mark narrow channels with 1"PVC pipes and the tops of the pipe are wrapped with the silver reflective tape, the type used down the side of tractor trailers. Yes it's designed to reflect light, and it does, but these channels show up like lighted runways on radar. I took some and applied it to a local day marker which has always been a poor radar target but not any more.
> I added a few pieces to the mast vertically and wrapped horizontally, near the spreaders. One would need to look for it to see it, even from the dock. The difference in the radar signature is dramatic! Radars love this tape.
> Put some on something and take a look with your radar at the before and after. I am sure you will be impressed. Even adding some to the flat surfaces of the Davis would probably make a good thing even better.


What you are saying is a real surprise to me! I use to build a product that used the reflective tape for bar codes in a greenhouse. I did a lot of experimenting with various types of reflective tape to get the best results. There are two kinds, one uses glass spheres that work by internal reflection. I suspect those wouldn't work. The other kind uses micro-molded corner cube reflectors, and the back appears to be aluminized. So that probably accounts for it working with radar.

It sounds like putting a strip of this stuff up you mast would give you incredible visibility to a search light, and work as a radar reflector. It doesn't get much better than that if it works as you say!


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## GaryHLucas (Mar 24, 2008)

sailingdog said:


> dugout-
> 
> do you have a link to the tape in question??


Look for a company called Reflexite, that's one brand I used to use. I don't know if this the one that works though. As far as I know they were the original inventors of the corner cube micro-molded product.


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## sailingdog (Mar 19, 2006)

Thanks Gary... I'll take a look and see what I can find out.


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## dugout (Nov 3, 2007)

sailingdog said:


> dugout-
> 
> do you have a link to the tape in question??


Sure, it's common stuff. It's more correctly called DOT reflective or Prismatic tape. I don't have enough posts for a link but these should be good clues. Just put the dots back in, change Xs to W and make cod into com.

XXX gemplers cod/product/10259/2x12-White-Reflexite-Reflective-DOT-Strips-4-pk]2"x12" White Reflexite® Reflective DOT Strips (4/pk.) - GEMPLER'S

This is some detailed information.
// dotsafetytape cod/DOT Approved Reflective Conspicuity Tape - BUY ONLINE

The white disapears on a mast. It's really cool stuff!

Be well!


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## rikhall (Feb 7, 2008)

sailingdog said:


> No, I just don't think AIS by itself is a good solution. You need to know where they are, but they also need to know where you are. Sometimes, you'll have a problem that prevents you from getting out of their way...and if they can't see you, you're screwed.


The last three summers we have had AIS on our 28 foot sailboat as well as radar and a radar reflector. With AIS I can see a boat coming around a corner or out of a harbour that I could never see on radar and that she could never see me no matter how many reflectors I was hanging out.

I can see a boat much farther away with my AIS (yes - assuming they are the kind of boat that is required to have AIS) than I ever can with radar.

So, alone - no, not my first choice, but as an inexpensive addition to my survival tools - you bet. When I already had FUGAWI, my laptop, radar and GPS, the $200.00 for an AIS receiver was a no brainer!


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## SeaFever12438 (Jan 16, 2009)

I was wondering if anyone else experimented with Reflexite. From what I've read about radar reflectors, it seems that their utility decreases a lot as size goes down -- you need at least a wavelength's dimension (or several) in your corner cube. So all those micro-cubes in Reflexite . . . how does that work? Like an army of ten thousand Lilliputians?

Anyway, if anyone else has empirical evidence on Reflexite, please let us know. Seems like a wonderful, simple, cheap solution -- if it really works.

---------------------------------------

Pasting in from my reading:

"The one thing that is key to the performance of any reflector design is size. The reflective performance of any type of reflector is proportional to the fourth power of its linear size. In other words, doubling the size of a reflector results in an increase of effective area of 16 times, or a 12 dB increase. Stated differently, an increase in size of a reflector of 19% will double its performance. *Further, as the smallest dimension of a reflector gets down to a few wavelengths of the radar signal, it quits acting as a reflector and starts to act as a lump of metal. *Remember that a wavelength is 3.2 cm (1¼") for X-band, and 10 cm (4") for S-band. So small detectors must be looked at with a great deal of suspicion, as there really is no substitute for size."

From ussailing DOT ORG /safety/Studies/radar_reflector_test DOT htm


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## GaryHLucas (Mar 24, 2008)

I have acquired a fairly large piece of coner cube reflector from one of my old sources and had planned on testing it at the end of this past season. Looks like a project for the spring now.

Interesting tidbit. You've probably heard of military aircraft using 'chafe' to fool radar seeking missiles. I always wondered how a bunch of aluminum foil could possibly reflect back a good signal. Guess what it is really made of?


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## sailingdog (Mar 19, 2006)

Actually, it is chaff, not chafe, which is what happens to halyards when you don't check the exit slots to lead fair.  What are they made of??


GaryHLucas said:


> I have acquired a fairly large piece of coner cube reflector from one of my old sources and had planned on testing it at the end of this past season. Looks like a project for the spring now.
> 
> Interesting tidbit. You've probably heard of military aircraft using 'chafe' to fool radar seeking missiles. I always wondered how a bunch of aluminum foil could possibly reflect back a good signal. Guess what it is really made of?


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## GaryHLucas (Mar 24, 2008)

You are right 'chafe' is what I do when someone corrects my spelling! The chaff is made of metalized corner cube material, like reflexite.


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## captxtina (Aug 5, 2008)

max-on said:


> . . . he also gave me some tips on mounting the reflector gained from his experience.


Hi. I plan on installing a Davis radar reflector on my Pearson 28 this week. I noticed the above comment indicating that there are better and worse ways to mount these. Do Tell! I've never done this before.

We were originally informed to drill holes in the spreaders, and put a mini-halyard up with a block so we can raise and lower the radar if need be. Is this right? Where along the spreader (inboard, outboard)? Note that when running downwind the sail does touches the spreaders.

Any tips are welcome. 
--Christina


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## GaryHLucas (Mar 24, 2008)

Patbarbeau said:


> I plan to sail my new boat on the St-Lawrence river where cargos are frequently present. I am installing a radar reflector but was wondering why the aluminium mast does not reflect radar itself? I am just curious to understand the difference especially since my reflector seems to also be made of aluminium??? Thanks for any source of info.


Radar, and light, only reflect back to the source from surfaces that are EXACTLY perpendicular to the source. Hence the only spot on a round or oval mast that can reflect directly back to the radar transmitter is a thin line running vertically. A square mast with flat surfaces would be even worse. IT would only show up if exactly perpendicular to the radar transmitter and that wouldn't happen often.

Radar reflectors use a corner cube principal. Three surfaces perpendicular to one another in a corner will reflect an incoming beam exactly parallel back to the way it came in. This is true for almost any angle of incidence, except exactly parrallel to any surface. Hence hanging it up in "rain catcher" position pretty much ensures that can't happen very easily. What blocks radar reflector the most is the mast! So two reflectors can work much better because both of them will never be behind the mast at the same time.

The very bright reflectors you see along the road are nearly all corner cube reflectors. Signs though are ussually made from glass sphere material which also exhibits a similar but not as bright effect.

Hope this helps,

Gary H. Lucas


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## sailingdog (Mar 19, 2006)

I'd point out that the radar reflector, especially one like the Davis Echomaster Deluxe,* should be hoisted on a halyard that runs through TWO blocks mounted under the spreader that are about a foot or so apart. *

This allows the Davis Echomaster to be hoisted without having it chafe the halyard it is being hoisted upon._

BTW, do not bother getting the "non-deluxe" version of the Davis Echomaster, as it really is a waste of money and does not come with the hardware to attach it to a halyard._

I'd point out that a line should connect one apex of the Davis Echomaster to the halyard running up, either via a loop or a bowline around the halyard. This will help prevent the Davis Echomaster from spinning in heavy winds.

Finally, the line should go from the bail on the top of the echomaster to the bail on the bottom, as a safety precaution.



captxtina said:


> Hi. I plan on installing a Davis radar reflector on my Pearson 28 this week. I noticed the above comment indicating that there are better and worse ways to mount these. Do Tell! I've never done this before.
> 
> We were originally informed to drill holes in the spreaders, and put a mini-halyard up with a block so we can raise and lower the radar if need be. Is this right? Where along the spreader (inboard, outboard)? Note that when running downwind the sail does touches the spreaders.
> 
> ...


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