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QinetiQ Funtington radar reflector tests
http://www.maib.gov.uk/cms_resources...s%20report.pdf
Recommendations · Based on the results of this report it is recommended that yachtsmen always fit a radar reflector that offers the largest RCS practicable for their vessel. · The RCS of the radar reflector should have a minimum consistent RCS of 2m2. · The Sea-Me is the recommended product if power is available · If power is not available then the passive Large Tri-Lens reflector is recommended · The 4” tube reflector is not considered suitable due to its poor performance. It is also recommended that the 2” tube reflector is not suitable since the performance of this target will be even lower. · It is recommended that poorly performing radar reflectors are not fitted as it is possible that the user could be lulled into a false sense of security believing that their chances of detection has been enhanced. |
QinetiQ Funtington radar reflector tests
Someone sent this to me a few days ago and I was going to post it but you
beat me to it. Wayne's reply to Skip's Look Out thread prompts this request to those in this group who radar consistently: The numbers in the British study aside, what do those of us in midsize fiberglass sailboats generally look like to you in the real world? Do you often see a boat with a radar reflector hanging that didn't show up on the scope? Are we little blips that you could easily overlook? How would you rate the chances of a vessel over running its visibility in fog not seeing a radar reflector equipped boat? -- Roger Long |
QinetiQ Funtington radar reflector tests
On Sun, 12 Aug 2007 07:53:27 -0400, "Roger Long"
wrote: The numbers in the British study aside, what do those of us in midsize fiberglass sailboats generally look like to you in the real world? Do you often see a boat with a radar reflector hanging that didn't show up on the scope? Are we little blips that you could easily overlook? How would you rate the chances of a vessel over running its visibility in fog not seeing a radar reflector equipped boat? Many, if not most, of the cruising sailboats I see offshore have some sort of visible radar reflector. They typically show up very well at 4+ miles. I believe we'd see most of them without a reflector based on my experience picking up small power boats. We see a lot of 20 something fishing boats in near shore conditions, invariably without any visible reflector. Most of them show up pretty decently also. Larger cruisers and sportfish show up very well, most without any sign of a reflector. A lot depends on the radar however. My 26 year old backup system does not do nearly as well and requires a good eye to separate targets from the clutter. Digital technology has advanced a lot in that time and it has made a big difference in my opinion. |
QinetiQ Funtington radar reflector tests
Moonshadow wrote in news:46becafc$1_3
@news.chariot.net.au: Based on the results of this report it is recommended that yachtsmen always fit a radar reflector that offers the largest RCS practicable for their vessel. http://www.shinemicro.com/RadarPlusSM162B.asp Too bad some powerful entities are causing the FCC to drag its bureaucratic feet on approval of this AIS TRANSPONDER that makes your little sailboat look like an aircraft carrier, setting off all the collision alarms on that 950' containership with the half-asleep seaman at the helm, waking him up. It will be most interesting to watch "them" telling the Admiralty Court why they didn't have the Class B targets turned on on the ships REQUIRED AIS system. It would seem that "We didn't see him.", the normal excuse for being run down by the ships, now all AIS equipped, would be moot if you had a real transponder firing away to the horizon. If I were a ship owner or insurer, exposed for the lawsuits, I'd be damned sure __ALL__ AIS targets would be displayed and acted upon on all my ships. It makes good business sense. These *******s keep calling me so I'm feeding them to the spambots. -- Sunrise Communications 1374 E. Republic Rd. Springfield, MO 65804 866-483-1228 417-886-7091 http://www.sunrisecommunicationsinc.com/ 877-842-3210 866-842-3278 United Healthcare http://www.unitedhealthcareonline.com/ |
QinetiQ Funtington radar reflector tests
....
Many, if not most, of the cruising sailboats I see offshore have some sort of visible radar reflector. They typically show up very well at 4+ miles. I believe we'd see most of them without a reflector based on my experience picking up small power boats. .... Sea conditions play a huge role here. If there are small power boats about you aren't at sea, you're near coastal. Over the last couple of decades of voyaging and delivery work and through many bridge to bridge communications I'd say that there is about a 50/50 chance that a large ship that is looking for you will see a mid-sized cruising boat with a radar reflector at four miles in anything less than ideal conditions in the open ocean. It is extremely rare in my experience for a ship to spot a small vessel offshore before being hailed. My experience has largely been in the Pacific and in many cases in remote parts of the Pacific and may not apply to the East Coast, but I think it is worth keeping in mind that as the seas get large and the radar less effective and the watches get less expectant of seeing vessels and less diligent your chances of both seeing and being seen go way down over what you might be used to in protected waters. -- Tom. |
QinetiQ Funtington radar reflector tests
"Roger Long" wrote in
: The numbers in the British study aside, what do those of us in midsize fiberglass sailboats generally look like to you in the real world? Do you often see a boat with a radar reflector hanging that didn't show up on the scope? Are we little blips that you could easily overlook? How would you rate the chances of a vessel over running its visibility in fog not seeing a radar reflector equipped boat? I have a friend who is a ham radio operator and ship master of a 950' SeaLand container ship. I asked him a similar question, so we went up on his bridge and fired off the ships radar at the dock in downtown Charleston, right in the harbor. It was Saturday and there were LOTS of small boats/sailboats to target..... The big radar antenna is, of course, way up on the mainmast probably 180' off the water, to the detriment of all the 50' radar reflectors it shoots completely OVER within about a mile of the ship. The radar antennas don't point down to avoid sea clutter mucking up the screens. So, the radiated beam is restricted by a plate under it to limit downward radiation. Once you're in the shadow of that plate, nothing will make you "seen" by the radar operator....when it counts the most. From the downtown dock on the seaward side of the Cooper River bridges, the first detectable targets I could see were about even with Ft Sumter on the OTHER side of the harbor. I used a really nice pair of stabilized binoculars to visually spot what I could see on the screen and the nearest target was a big sloop showing a radar reflector hanging under his spreaders. The other targets moving around were past Ft Sumter out in the ship channel. Even then, most of the sailboats never made a dot on the screen with no reflector. The steel ships all made quite a blob, even way out to our horizon. Some of the shrimp boats had a return shrimping offshore. Most of the plastic bubbleboats, even those 60' monsters barely showed up unless they had a reflector, either. This is all with the ship sitting perfectly upright and having a clear view of the horizon on a clear day. From the bridge, I could see quite a ways at sea out past the Jetties and offshore to the South over Noname Island by Ft Sumter. I'm sure if your radar reflector were at 50' in 6' seas, or worse, and the monster ship were rolling, you'd make even less of an impressive blob than I saw. If you ever get a chance to try it for yourselves, do light it off and test your own theories. I sure wouldn't depend on the radar op seeing my 40' plastic boat at all, radar reflector or not. I think it's wishful thinking and a LOT of luck. Cap'n Larry told me to tell all my sailor friends that NOONE on his ship is bothered, at all, if you CALL THEM ON CHANNEL 13 OR 16 TO LET THEM KNOW YOU ARE THERE! I've always gotten a thank you from their bridge after asking them if they see us crossing their path. Some did...many didn't! Why sailors are so goddamned TIMID to talk to ships on the radio has always been a mystery to me. Those guys on the bridge are BORED TO TEARS! They're not busy, at all, as the ship drives itself. Especially on the midwatch, I've spent hours talking to whatever mate is driving on Channel 13 out beyond land. There's just you and him and you're not jamming the dead channel at all. I declined one mate's offer to swap Geoffrey's Endeavour 35 for a 450' freighter full of bananas and fuel....(c; Both our captains were asleep...hee hee. How many bananas can YOU eat?...(c; You'll find them ALL very curious to know all about your boats. They've never been sailing. These *******s keep calling me so I'm feeding them to the spambots. -- Sunrise Communications 1374 E. Republic Rd. Springfield, MO 65804 866-483-1228 417-886-7091 http://www.sunrisecommunicationsinc.com/ 877-842-3210 866-842-3278 United Healthcare http://www.unitedhealthcareonline.com/ |
QinetiQ Funtington radar reflector tests
On Sun, 12 Aug 2007 11:34:21 -0700, "
wrote: ... Many, if not most, of the cruising sailboats I see offshore have some sort of visible radar reflector. They typically show up very well at 4+ miles. I believe we'd see most of them without a reflector based on my experience picking up small power boats. ... Sea conditions play a huge role here. If there are small power boats about you aren't at sea, you're near coastal. Agree on both counts. Most of the prior discussion relates to near coastal cruising. Over the last couple of decades of voyaging and delivery work and through many bridge to bridge communications I'd say that there is about a 50/50 chance that a large ship that is looking for you will see a mid-sized cruising boat with a radar reflector at four miles in anything less than ideal conditions in the open ocean. It is extremely rare in my experience for a ship to spot a small vessel offshore before being hailed. My only experience with commercial vesels is in near coastal, relatively calm conditions. I know that I have been spotted in those circumstances, even with out a reflector. We're a bit bigger than the average cruising sailboat however. My experience has largely been in the Pacific and in many cases in remote parts of the Pacific and may not apply to the East Coast, but I think it is worth keeping in mind that as the seas get large and the radar less effective and the watches get less expectant of seeing vessels and less diligent your chances of both seeing and being seen go way down over what you might be used to in protected waters. Makes sense unfortunately. |
QinetiQ Funtington radar reflector tests
Larry wrote:
If you ever get a chance to try it for yourselves, do light it off and test your own theories. I sure wouldn't depend on the radar op seeing my 40' plastic boat at all, radar reflector or not. I think it's wishful thinking and a LOT of luck. Aww crap Larry...now all I gotta do is find a genuine Homeland Security approved active ECM critter and I'm good. Wonder how the Coasties and Skimmers will feel about this... |
QinetiQ Funtington radar reflector tests
In article ,
Larry wrote: The big radar antenna is, of course, way up on the mainmast probably 180' off the water, to the detriment of all the 50' radar reflectors it shoots completely OVER within about a mile of the ship. The radar antennas don't point down to avoid sea clutter mucking up the screens. So, the radiated beam is restricted by a plate under it to limit downward radiation. Once you're in the shadow of that plate, nothing will make you "seen" by the radar operator....when it counts the most. Ahhh, Larry but you didn't gives us the most important piece of information abut this "BIG" radar. Was it X-Band or S-Band????? That will make a HUGH difference, in what Targets it paints, at what distance.... ALL these 1500 Gross Ton or larger carry both...... Bruce in alaska -- add a 2 before @ |
QinetiQ Funtington radar reflector tests
Larry wrote:
I suppose my point is plastic boat sailors THINK the big guys can spot them, on radar and visually. I suppose they COULD if we move the bridge to the bow or take off all the containers in the way, but that isn't gonna happen. The flag is 930' in front of the helm. You all know what the genoa does to your ability to see those damned crabpot toilet floats from your helm. Imagine if the obstruction were 900' FORWARD of your bow! They can't really see anything less than a full sized ship, on radar or out the windows. There are hardly any sailors aboard these huge ships run by computers. The crews are, to increase profits, tiny in respect to the size of the beast. There aren't 15 people with binoculars standing on the bow, in a crow's nest looking out for icebergs and Catalinas, guys standing on the bridge wings scanning the horizon for 4 hours like a Navy ship has. There's one guy, walking around the bridge, bored to tears as the computer watches the GPS and flogs on towards Holland....just like last week, last month, last year... (yawn).....zzzzzZZZZ. I think (from memory) the IMO rules require you to see only 2 boat lengths from the BOW. So visibility can be impaired say anywhere within 1800' of the bow... I ALWAYS assume I am invisible to big ships and steer accordingly. On offshore passages I've called passing ships and ask if they can see me on radar. Often the reply is "let me get it warmed up"... Evan Gatehouse |
QinetiQ Funtington radar reflector tests
On Aug 14, 5:25 pm, Evan Gatehouse
wrote: .... I think (from memory) the IMO rules require you to see only 2 boat lengths from the BOW. So visibility can be impaired say anywhere within 1800' of the bow... .... I haven't read the IMO treaties and case law but the way it was taught to me was that a lookout had to be as far forward and low as practicable (preferably but not necessarily off the bridge). Five, as written, clearly doesn't allow 1800' blind spots, but maybe the courts do. However, I don't mean to quibble. You are absolutely right to assume that you are invisible to all targets that pose a risk of collision unless you have had positive communication with them and come to a passing agreement. -- Tom. |
QinetiQ Funtington radar reflector tests
Evan Gatehouse wrote in news:Bmuwi.58787
$_d2.38488@pd7urf3no: I've called passing ships and ask if they can see me on radar. Often the reply is "let me get it warmed up"... I think that's a more common response than we'd like to think about. They just don't care or have the time to care....which makes no difference as you go under the bulb. Sailors offshore need to take a more intense interest in calling them to KEEP THE WATCH AWAKE, out of his stupor, especially on the midwatch. |
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