Association Forum - Radar reflectors

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Radar reflectors

New Topic

Topic Locked

Printer Friendly

Author

Topic

Page: of 2

Oscar
Master Marine Consultant

Members Avatar

USA
2030 Posts

Response Posted - 04/12/2007 : 13:27:49

Good article. Answers my long lingering question about the reflective flag.....fogeddaboutit.

The tri-lens seems to be the winner, although not as effective on s-band as on x-band. The former is when I need it most......

Thanks a lot.....anothr $500 item on my wish list.....

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 04/12/2007 : 15:32:22

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Oscar
 The tri-lens seems to be the winner, although not as effective on s-band as on x-band. The former is when I need it most...... Thanks a lot.....anothr $500 item on my wish list.....

<hr height="1" noshade id="quote"></blockquote id="quote">
My heart bleeds!

Seems to me on a 42-footer that's about the cost of a pair of winch covers.

That big Tri (5 BUs) might be considerably better for S-band than the standard size, since the lense diameters are more than 2 wavelengths. Where I expect to be, they'll have their X-band on. I'm more worried about fast ferries, tugs with tows, and big SeaRays racing to and from Block Island. The latter will be invisible on my screen--primarily because they don't know they need a reflector. Damned stinkpotters!

Edited by - Dave Bristle on 04/12/2007 15:37:08

Oscar
Master Marine Consultant

Members Avatar

USA
2030 Posts

Response Posted - 04/12/2007 : 16:19:48

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Seems to me on a 42-footer that's about the cost of a pair of winch covers<hr height="1" noshade id="quote"></blockquote id="quote">

Actually, it's not too bad. As long as you do EVERYTHING yourself, and have the resources to make many parts and pieces you can do pretty well. After the shock of the first year it's pretty much down to regular maintenance, and as I said, I do that myself.

Edited by - Oscar on 04/12/2007 16:20:44

redviking
Master Marine Consultant

Members Avatar

USA
1771 Posts

Response Posted - 04/17/2007 : 17:03:18

About the MOBRI - I just received the Life Raft & Survival Equipment catalogue, and these folks sell the MOBRI - it doesn't look like the Defender model at all. I decided to google MOBRI and found the following...Proven superior, named best Radar Reflector by US Coast Guard ... the standard by which all other reflectors are measured
The Mobri was first tested in 1980 by designer Mogens Pederson with fishermen and yachtsmen in Denmark. Tests were also carried out at the Admiralty Research Department in England with favorable results. To date many thousands have been sold worldwide to sailors, power boaters, and fishermen, as well as to the U.S. and Canadian Coast Guards for use in navigational buoys.

http://www.uscg.mil/systems/gse/gse2/Specifications/450-D.pdf

I googled MOBRI on the Coasties website and came up with the MOBRI spec'd for buoys and the like...

sten

Edited by - on

Oscar
Master Marine Consultant

Members Avatar

USA
2030 Posts

Response Posted - 04/17/2007 : 18:40:25

That's a much better price!!!

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 04/17/2007 : 20:42:34

From what I can deduce, the Mobri will be reliably seen from forward or aft of your boat, since it will be generally perpendicular to the radar. (A friend reported that when following another friend's boat in fog, their Mobri shined nicely on his screen.) From the side, the returns apparently depend greatly on a sailboat's angle of heel, going to zero at 20 degrees or so (up or down). So one solution might be to set up three Mobris--one parallel to the mast, one angled 20 deg. to port, and one 20 deg. to starboard. Then, from abeam, at least one of the three will be perpendicular whether you're motoring or sailing on either tack. Perhaps one each on the upper shrouds above the spreaders and one on the mast.

Alternatively, you could assume that you'll be under power or sailing upright in poor visibility or at night--then it appears one Mobri will do. However, note that the CG calls for multiple Mobris within a bouy.

Otherwise, I'd opt for the TriLens (also three reflectors built in, but Lunebergs.) I believe the TriLens came out after 1998 (the date of the document linked above).

Edited by - Dave Bristle on 04/17/2007 20:53:14

redviking
Master Marine Consultant

Members Avatar

USA
1771 Posts

Response Posted - 04/17/2007 : 21:37:21

OK, WM has one "mini" TriLens for $150.... Sold.

Then again....Nearly all of my fog runs have been vertical under power. I'm afraid of my 135 jenny chafing as it comes across the TriLens on a tack. Probably wouldn't, and admittedly I secretly want one because it would look cool. I just worry that the "mini" isn't any better and I've drilled holes in my mast for not much more.... The Coasties spec'd the Mobri in 1998 and Practical Sailor rated the Tri in 2001... No better technology has emerged since then? Coasties didn't switch to the Tri or any other design that I can tell - so I do believe that it does work - preferably as stated before, in the vertical position.

sten

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 04/17/2007 : 22:00:29

Speaking of Lüneburg, if you are ever in Hamburg, take a drive over to Lüneburg. Nice town...Lübeck to the north is pretty amazing.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 04/18/2007 : 07:42:34

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by redviking
 OK, WM has one "mini" TriLens for $150.... Sold.<hr height="1" noshade id="quote"></blockquote id="quote">
P/S didn't like the Mini. For $50 more (regular size at Defender) you get something like 4x the return. I haven't seen any new info from the CG, but the Navy uses Luneberg lenses (as in the Tri). That said, under power and vertical, the Mobri appears to be adequate. (Note that the CG specifies the M-series, which is larger in diameter than the S-series.)

Edited by - on

redviking
Master Marine Consultant

Members Avatar

USA
1771 Posts

Response Posted - 04/18/2007 : 08:58:26

Thanks Dave - i did catch the M series reference, however the catalogue from Life Raft and Survival shows the 2" diameter M and S series at a range of 3 miles or less... The 4 inch diameter model either S or M series is rated for 3 plus miles... Either way, plenty for me in Narragansett Bay and Long Island Sound...

sten

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

Members Avatar

USA
4479 Posts

Response Posted - 04/18/2007 : 21:45:02

Having decided to purchase a Tri-lens, I spent a bunch of time online looking for the best price. I found a vendor who has the standard reflector for about $180. The website seemed to be wanting to charge me California state tax even though I live in Washington, so I called the company to ask about it. I ended up talking with the owner and after some negotiations he's going to offer the members of our association a group discount similar to what we're getting from Online Outboards. We will be able to purchase a Tri-lens Standard for a bit less than $170 plus shipping (and tax if you live in CA). The details are still being worked out, but expect the offer to be up and running over the weekend. I'll start a new thread when we have the deal finalized. The next best deal I was able to find was more than $20 more. So Sten if you haven't bought your mini yet, and don't mind another $20 for a standard, you'll be able to order one this weekend.

Edited by - delliottg on 04/18/2007 21:49:36

DaveR
Master Marine Consultant

Members Avatar

USA
2015 Posts

Response Posted - 04/18/2007 : 22:17:41

When I read this tread I remembered That I had a radar reflector. It came with the Quicksilver inflatable I bought (another story). Turns out it's a Davis Echomaster 153. Pretty cool. I'm not in an area where I have to deal with a lot of commercial traffic but awful nice to have!

Edited by - on

britinusa
Web Editor

Members Avatar

USA
5404 Posts

Response Posted - 04/19/2007 : 07:06:06

This is one of the threads that I didn't read till now, not a high priority subject for our primary sailing zone (at least that was my thought on first seeing the subject line.)

Having read the posts to date, it reminded me of the value of this forum.

All of the testing agencies out there, particularly those of sailing magazines that have much more limited testing facilities, tend to have a singular point of view, that obtained from their own tests.

This forum brings a whole bunch of views together, expands the subject, adds anecdotal stories, practical experience, personal preferences, and additional issues to the plate.

We really do have an incredible valued forum here.

Just wanted to offer appreciation.

Paul

Edited by - britinusa on 04/19/2007 07:07:01

Nautiduck
Master Marine Consultant

Members Avatar

USA
3704 Posts

Response Posted - 04/19/2007 : 13:04:34

David, thank you for working on this. I will order the tri-lens after you post the info. That is a great price.

We did just put the mast up but maybe this is an opportunity to hoist the Admiral up the mast. Heck the tri-lens will go just above the spreaders, not that high.

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

Members Avatar

USA
4479 Posts

Response Posted - 04/19/2007 : 14:05:09

Randy,
Above the spreaders should be fine, that's where I plan to mount mine as well, although I'm a bit worried about vertical clearance with it while trailering as it'll add an additional foot to the height of the trailer.

Here's an email exchange with Tim Rozendal, the makers of the Tri-lens:

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Good afternoon,
I've been doing research on radar reflectors for my sailboat and have concluded that the standard Tri-Lens is the most appropriate for the safety of my family and my boat. It's a masthead rig boat, so I can't easily mount the reflector just above the mast dogs like you could on a fractional rig, so I've got some questions:

* Is higher better as far as "visibility" to inbound radar energy? In other words, the closer I can get it to the top of my mast, the better? Or could I mount it about at my spreaders (maybe 20+ feet above the water line?) and call it good?
* Will the reflector interfere with VHF transmission / reception if it's situated very near my antenna? Conversely, will the antenna interfere with the reflector's ability?
* Presuming at some point I add my own radar set will the reflector interfere with it's operation if it's vertically above or below it with some separation? For instance the Tri-Lens at the spreaders and the radome 2-3 feet higher on the mast?

Thanks for your time,
Sincerely,
David

Tim Rozendal <trozendal@rozendalassociates.com>
Apr 11

David,

20 feet above the water level would be great, higher is not necessary better. The tri-lens will not interfere with UHF or conversely. As long as the tri-lens is below or above a radar system there is no interference.

Tim Rozendal

Rozendal Associates, Inc.
9530 Pathway Street
Santee, CA 92071
Telephone: (619) 562-5596
trozendal@rozendalassociates.com
<hr height="1" noshade id="quote"></blockquote id="quote">

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

Members Avatar

USA
4479 Posts

Response Posted - 04/23/2007 : 10:16:27

OK, the deal with [url="http://www.downwindmarine.com/xcart/home.php"]Downwind Marine[/url] is up and running. I'll start a new thread with the details.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 05/23/2007 : 08:44:33

Here's more than you ever wanted to know, from a 2007 study in the UK...

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

It seems to indicate the Tri Lens is the best reasonably affordable option for a sailboat (considering heel angles), and the standard size is adequate if not spectacular... (See Section 5 - Conclusions.)

Edited by - on

Page: of 2

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.