Sailing yacht radar visibility

[Bobc]

I am aware of the variables of when it comes to radar range, such as the height of the radar, height of the target, power of the radar, sea conditions, etc.

Someone was telling me recently that a sailing yacht, even with the sails up, has very poor radar reflective capabilities. According to him a large ship with a radar mounted high up, in most cases could only see a 30 foot sailing vessel from only 3 nautical miles away!

Is this true?

I'm sure we have some recreational users with radars fitted, is a small sailing vessel without any radar reflectors really only visible from within a few miles?

I had an encounter with a ship in fog in the English Channel a couple of years back. The ship was passing behind me (I could see him on AIS and radar) and then he altered course and steered directly for me. He was only about 1km away, so I called him up to ask if he could see me on his radar. He said that he couldn't.

This was a 50ft yacht under full sail with an Echomax radar reflector fitted.

You must assume that they can't see you, no matter what you have fitted I'm afraid.

 

[Daydream believer]

Multiple radar reflectors on a yacht CAN under some conditions cause an incoming search pulse to miss you by cancelling the return signal in some way. Stick with one and please dont buy the tube type Mobri.

Conversely:-Following a discussion with a "friend of a friend into naval radar " I was told that the sum of 2 reflectors can often be greater than the 2 individual components. I , therefore, fitted 2of 4 inch diameter Plastimo reflectors which in tests are said to be useless. I fitted them on the mid shrouds so that they were angled. The idea being that one should always be nearer vertical, if that was possible.
I had occasion to be assisted by the RNLI when taken ill one night in very rough weather ( max speed of the lifeboat 11kts & I was doing 5.3 kts under bare poles as recorded by CG)
After the rescue the Coxswain came to see me to look at my reflectors. He said that the return in the waves was extremely good. I said that was down to his posh gear & he said no because his boat was down to have new radar fitted shortly.
So perhaps there is something in the 2 reflector theory
That being said I later fitted AIS transponder & Echomax 2 band & an Evergreen container ship missed me by less than 2 boats lengths & sailed serenely past blissfully unaware of my existence. On another occasion Polarstream, a supply vessel, changed course in the channel, almost running me down.
The moral being- If they ain't looking it does not matter how good your gear is. Just make sure that you are looking.

 

[JonWA]

So, given various 'they won't see you anyway' accounts, I'm thinking I'll rely on AIS transceiver and not bother with fixed reflector which seems to be all but useless when you really need it. Sounds like it's best to assume they won't see you,

 

[wully1]

In some yotty magazine test several years ago the conclusion was that a GRP boats engine gave a better radar reflection than a ‘radar reflector’

A bunch of scrunched up aluminium foil inside a plastic box riveted onto several meters of aluminium does not convince me of their worth.

An active transponder + AIS + your own radar (and the knowledge to use it) if you are that worried.

 

[jamie N]

I've no connection with Echomax, but if you're in any way serious about 'being seen', then anything else isn't enough.

 

[Sandy]

All sorts of answers coming in.

Let me phrase this another way. If you were in a 30 sailing yacht with the sails up, with or without radar reflector, do you think any radar could reasonably pick it up from 20 nm away?

It's not the ship's at 20 NM I worry about its the ones at 1 NM.

 

[st599]

My question is WITHOUT radar reflector.

The guy is trying to convince me to fit radar reflectors. So I'm interested in knowing APPROXIMATE visibility without radar reflector compared to with. And is his line about a yacht with the sails up and no radar reflector only being visible from 3 nm away true?

After Ouzo got run down, Qinetiq (defence research establishment) did some tests. It's available on the net somewhere.

Conversely:-Following a discussion with a "friend of a friend into naval radar " I was told that the sum of 2 reflectors can often be greater than the 2 individual components. I , therefore, fitted 2of 4 inch diameter Plastimo reflectors which in tests are said to be useless. I fitted them on the mid shrouds so that they were angled. The idea being that one should always be nearer vertical, if that was possible.
I had occasion to be assisted by the RNLI when taken ill one night in very rough weather ( max speed of the lifeboat 11kts & I was doing 5.3 kts under bare poles as recorded by CG)
After the rescue the Coxswain came to see me to look at my reflectors. He said that the return in the waves was extremely good. I said that was down to his posh gear & he said no because his boat was down to have new radar fitted shortly.
So perhaps there is something in the 2 reflector theory
That being said I later fitted AIS transponder & Echomax 2 band & an Evergreen container ship missed me by less than 2 boats lengths & sailed serenely past blissfully unaware of my existence. On another occasion Polarstream, a supply vessel, changed course in the channel, almost running me down.
The moral being- If they ain't looking it does not matter how good your gear is. Just make sure that you are looking.

2 reflectors could increase the signal or null it out. Depends on orientation and distance between them.

 

[john_morris_uk]

I’m a bit confused/bemused by one or two comments. It’s basic seamanship to assume you haven’t been seen. It doesn’t mean you don’t give way as required and stand on as required. It just means if you’re stand on you stand on and watch carefully. (Exactly in accordance with IRPCS) AIS is a great aid here as you can see what the ships are doing. It’s no good complaining about the wonderful radar reflector you bought if circumstances (including poor watch keeping) means you were involved in a collision.
However in my experience 99.9% of ships keep a lookout and comply with IRPCS. It helps if yachts do the same. I admit that most collision avoidance on a ship is done by radar and it helps if you can be seen by radar.

 

[Daydream believer]

I’m a bit confused/bemused by one or two comments. It’s basic seamanship to assume you haven’t been seen. It doesn’t mean you don’t give way as required and stand on as required. It just means if you’re stand on you stand on and watch carefully. (Exactly in accordance with IRPCS) AIS is a great aid here as you can see what the ships are doing. It’s no good complaining about the wonderful radar reflector you bought if circumstances (including poor watch keeping) means you were involved in a collision.
However in my experience 99.9% of ships keep a lookout and comply with IRPCS. It helps if yachts do the same. I admit that most collision avoidance on a ship is done by radar and it helps if you can be seen by radar.

I think that is a very important comment. I often see remarks on the forum where forumites state that they just keep out of the way of big ships. However, unexpected changes of course by yachts must be very confusing to a ship with limited manouverability. I have had ships call me up as far away as 8 miles & actually asked me NOT to change course. I have had some call & ask me to confirm my track. ( possibly because I have been wandering a bit due to wind variation) .Then ask me to hold that course.
Sometimes I have called them & asked if they want me to change & more often than not they will say no. If there is traffic, as in the Dover Strait, or more towards the Netherlands they do sometimes ask me to change my direction of travel. But we agree it first.

 

[Stemar]

Unfortunately, the biggest part of being seen is someone actually looking.

I always work on the basis that, especially on smaller ships, there's only one bloke on watch, and he's watching porn and/or halfway through his bottle of vodka. When I'm proved wrong, which I usually am, it's great; on the rare occasion I'm right, at least I'm ready for it.

 

[Neeves]

Our communication, VHF, with large commercial vessels, primarily bulk carriers (coal, iron ore and bauxite) have always been, immediate, courteous (in the extreme, clear and positive.

They are always, reassuringly, aware of our presence.

Jonathan

 

[Bobc]

Our communication, VHF, with large commercial vessels, primarily bulk carriers (coal, iron ore and bauxite) have always been, immediate, courteous (in the extreme, clear and positive.

They are always, reassuringly, aware of our presence.

Jonathan

Whenever I've felt the need to call up a ship on VHF, they've always been very polite and helpful. Better to call them up early and agree a plan than later when you're trying to avert disaster.

 

[fredrussell]

Recently someone posted a link to a MAIB report where they tested various radar reflectors. It wasn’t long ago, anyone recall it and able to link to it?

 

[rogerthebodger]

The Spirit of Tasmania, a car ferry, used to run from Sydney to Devenport in Tasmania, the standard route is Melbourne to Tasmania. They were following us down the coast (and passed us ) and picked us up at 16nm. We knew they were behind us and had spoken to them on VHF as we were on the same passage - so they were specifically looking for us. We had a long chat with them about radar. Cruise ships are very attentive to small craft - but usually have a much larger ships crew than other large commercial vessels.

I think a lot depends on how much attention is being paid by the crew on watch and location. I suspect more attention is paid in the English Channel or Singapore Straits than crossing the Pacific.

On the east coast of Australia we have the East Australian Current running from north to south. Any ships or yachts transmitting the coast try to piggyback on the current, so all going south follow the same passage plan and all going north are closer in shore. So - going south we watch our backs . Going north is not such a big issue as yachts can get much closer inshore than a commercial ship would risk.

Jonathan

We have almost the exact setup on the east coast of Africa. The has only been one time where I had to call a ship that did not see us on radar. This was at night and once I raised the OOW he came on the radio in a very sleepy voice.

This was in a 50 ft GRP boat without a AIS transponder only a AIS receiver displaying on the chart plotter.

 

[johnalison]

With my own radar I generally see yachts at about 2 1/2 miles, sometimes a bit more or less. I have tried to check with a friend's Sea Me to establish the distance for that but didn't do enough to come to a firm conclusion, though it clearly worked. By extrapolation, I assumed that ships see us at double this distance, possibly more. I would regard a folding octahedral reflector as the absolute minimum for anyone going into waters with shipping, and the rigid type fixed to the mast for anyone doing this regularly. An active 'transponder' type is so obviously superior that I would expect anyone who can afford one to fit one.

 

[Graham376]

When sailing in a flotilla some years ago, some of us played with our radars. A few nearby yachts without reflectors showed up on our Furuno, some further away with narrow diameter (toy) reflectors didn't, those with Blippers or Echomax showed up well. We have an Echomax on this boat and when I've called up ships, they've usually seen us at 8 -10 miles, occasionally further. As said before, SOLAS requires a reflector to be fitted if possible and I wouldn't want to be without.

 

[mattonthesea]

I think that is a very important comment. I often see remarks on the forum where forumites state that they just keep out of the way of big ships. However, unexpected changes of course by yachts must be very confusing to a ship with limited manouverability. I have had ships call me up as far away as 8 miles & actually asked me NOT to change course. I have had some call & ask me to confirm my track. ( possibly because I have been wandering a bit due to wind variation) .Then ask me to hold that course.
Sometimes I have called them & asked if they want me to change & more often than not they will say no. If there is traffic, as in the Dover Strait, or more towards the Netherlands they do sometimes ask me to change my direction of travel. But we agree it first.

Apart from I've never been called I was going to say exactly the same.

Out in the ocean, when called, you can tell if they've seen you by the length of the pause after you ask them.

Are you aware of my presence?
pause < 1 sec, Yes = Yes
pause >1 sec, Yes = No ?

 

[rogerthebodger]

Apart from I've never been called I was going to say exactly the same.

Out in the ocean, when called, you can tell if they've seen you by the length of the pause after you ask them.

Are you aware of my presence?
pause < 1 sec, Yes = Yes
pause >1 sec, Yes = No ?

I find monitor my AIS receive , if the ship has a particulate CPA and the CPA starts to get larger the ship OOW has seen you it it does not they haven't

 

[CAPTAIN FANTASTIC]

Overall, the low cost radar reflectors have a mix performance, sometimes they work really well sometimes don't work at all, pending on many variables. I used the ordinary reflectors over the years in the 80' and 90' where that's all we had. Nowadays, I would install the active reflector variety to ensure effectiveness. However, at present I only have an AIS transponder; also, I would never rely to seen by others.

 

[rotrax]

All sorts of answers coming in.

Let me phrase this another way. If you were in a 30 sailing yacht with the sails up, with or without radar reflector, do you think any radar could reasonably pick it up from 20 nm away?

Unlikely.

A sailing mentor who was a JSASTC Skipper was off the Canaries in a Nic 55 when the QE2 passed within within view.

He spoke with the bridge and asked about the Radar signal of the Nic 55.

Despite having a big Echomax he was told it was poor and intermittent.

There was a big swell running and the signal would deteriate in the troughs.

Thinking was the Radar pulse was going over the top when the Nic 55 was in a trough.

Another time, off Caribean Columbia he was called up at night by a US Warship on anti drug smuggling duty.

" Who are you, what are you, what are you doing? " he was asked.

After answering he said " You seem to have the advantage of us. We have the best leisure Radar available but we dont have you on our screen. You, however, have us located to the last decimal point. "

A blip came up on his Radar screen some miles further offshore and the laconic American voice said " Is that better...................."