Active Radar Reflector - My recent experience

[lw395]

Irrelevant, because a ship in unrestricted open water will not be aiming to miss by a hundred yards. Half a mile at a minimum, I would guess, and a mile or two is better.

pete

Where is this unrestricted open water of which you speak?
A ship in the English Channel not only has yachts to dodge, also the other ships on roughly parallel courses.
But yes, they are typically panicking if they think you are coming within 500m.
That is not many boat lengths to them, I think we underestimate how far away they are visually.

 

[Conachair]

It's an interesting comment but I'm wondering how realistic it is. Dont for a minute doubt that you think you are correct but at 20 miles a one degree change of course would miss a target by 700 metres. So if a big ship thought it necessary to take avoiding action and miss you by 100m , he would need to change course by 0.15 degrees only. Even at 5 miles he would only need to change course by 0.6 degrees

Does AIS record courses to that accuracy?

Plus of course, at 20kn it takes an hour to cover 20nm. What yacht keeps a steady course for an hour. Or even 10 minutes?

I'll check the log just in case i wrote any of it down, but from memory it was more like a 10deg for a few miles then back to previous course to give me some more miles searoom, clearly visible dog leg on the ais screen.
A yacht going downwind in the trades with a windvane will keep a fairly steady course for weeks

 

[Conachair]

Irrelevant, because a ship in unrestricted open water will not be aiming to miss by a hundred yards. Half a mile at a minimum, I would guess, and a mile or two is better.

pete

That was my experience, they always gave me loads of room. And from watching the ais often any actions taken to do so took place a long way away, even before you could see the ship.

 

[alant]

I agree in part... it really can depend upon the sailing you are likely to be doing.

In the past though I have been caught in a white-out during a day sail off Osborne Bay (Solent), and instead of one crew up front with a fog horn and me dreading the thought of a big ship coming through the gloom, I am now able to 'see' and 'be seen' by having an ais receiver, radar and an Active radar reflector.

Last winter I set the boat up for longer cruising.
This summer a 5 month trip going to Scotlands Western Isles and back from Portsmouth was accomplished.
We did use the radar, ais and Active radar reflector several times during the two thousand miles and most important for me, it gave swmbo far more confidence when she could concentrate her efforts on collision avoidance rather than "When we're hit, what shall we do first?"

The extremely sad result of the Ouzo recently may have been avoided if more money had been spent on 'toys'
Just a thought

Presumably in a T35, your real concern, is not being able to get out of the way quickly enough?

 

[Tidewaiter2]

Echoes to Port, to Stbd, dead ahead and astern , suggest we sink where we are

WTF are you on about, Sailorman ? One minute you are on about ships 10 miles away, now 75miles away.

When crossing shipping lanes, its not the ships you can visibly see as the closest that are the problem, they pass in front of you, it is the ones just over the horizon which create the closest CPA.

WTF are you on about, Sailorman ? One minute you are on about ships 10 miles away, now 75miles away.

When crossing shipping lanes, its not the ships you can visibly see as the closest that are the problem, they pass in front of you, it is the ones just over the horizon which create the closest CPA.

+1, it's the fact that they are doing perhaps twice your best speed or more than, in staggered echelon, on parallel courses, spread across the whole TSS width, or off the Cherbourg Penisula, where you have no TSS, but Ships joining the main flow from the Race, the Seine, the Inshore Zone,or heading for Soton, or the Westbound TSS + the ferries.Oh, and fog when the tide turns usually.

Lots of targets on the AIS, but with our 20nm pick up, you can think long term about your tactics as they close to visual on the horizon and 6nm on the radar rings+ AIS gives so much info as to speed, COG, etc.

It eases that total rabbit in the headlights/nut in the cracker jaws feeling, that you got before we had a boat with AIS and radar

Even so, returning in August, I had to gybe and parallel one east bound tanker (as per John Goode's PBO booklets{remember them?}) til it was past and clear, it was definitely aiming at a sub 400m CPA (or else the OoW was having their Tomtit)

Experts; Would an RTE dual band on a pushpit pole height about 3m overall above sea level give you a strong echo out to 10nm with say 20 degree heel max?
The OP seems to have had less than calm xing conditions, and that's when you need a good return to traffic.

 

[lw395]

....
Experts; Would an RTE dual band on a pushpit pole height about 3m overall above sea level give you a strong echo out to 10nm with say 20 degree heel max?
The OP seems to have had less than calm xing conditions, and that's when you need a good return to traffic.

I wouldn't say I'm an expert (because you're not paying me!), but
The ship's radar will be installed high enough to give a 10nm horizon
The 20 degree heel is close to where the RTE falls over, but you are not going to be heeling directly towards the ships you have CPA problems with.
The output power of the RTE is plenty to be seen.
I think it ought to work, but not having full information, the heel angle concerns me a little.
It would be interesting to have the conversation with the people who designed it.

 

[SHUG]

I sailed to the Med in 2003 without SeaMe and had quite few "Collision" prospects even though I was the right of way vessel. ( I know that's another debate). After fitting SeaMe in 2005 the situation changed significantly and large vessels would change course appropriately.
When discussing this with a professional seaman ,he told me that on large vessels the radar display is recorded and if a significant signal appears on the screen and the Collision Avoidance System indicates a possible collision then they MUST make a course alteration. If there subsequently was a collision, then the evidence could be damming.
The signals from yachts is usually not significant amid the clutter so it is usual to resort to visual observation if avoidance is thought to be necessary.
So keep your active reflector on in shipping lanes even in good visibility or at any time when ships are around.
Better safe than..................

 

[bbg]

Coming a bit late to this thread but FWIW ---

To those who think a lot of these will clutter up ships radars in tight waters:
- my understanding is that they give STRONG (i.e. clear) radar returns, not LARGE radar returns.
- I have been told that it is illegal to have them switched on within a certain distance of the French coastline, specifically to avoid the problem of overcrowding ships' radars. I would nevertheless use one in fog, at night or in heavy ship traffic if I thought it would help

An anecdote. A couple of years ago my nav lights failed and I was forced to use those useless D cell emergency lights (as an aside, after that experience I got a couple of Navisafe emergency lights). On two occasions (with my RTE switched on) I passed half a mile or so away from a fishing boat. Absolutely no risk of collission, but as I got nearer both boats swept the sea and eventually lit me up with their spotlights. I suspect that they saw the strong radar return but didn't see the useless deck-level lights, and wanted to see what was out there.

Obviously I have no idea if they would have done the same without the RTE, but I will definitely have one on my next boat.

 

[lw395]

Coming a bit late to this thread but FWIW ---

To those who think a lot of these will clutter up ships radars in tight waters:
- my understanding is that they give STRONG (i.e. clear) radar returns, not LARGE radar returns.
- I have been told that it is illegal to have them switched on within a certain distance of the French coastline, specifically to avoid the problem of overcrowding ships' radars....

By 'strong, not large' do you mean a powerful signal level coming from a small area?
They are certainly a powerful signal.
The area that they 'appear' to come from will be dictated by the beamwidth of the radar antenna, which will be 1 to 2 degrees at a guess. The radar can't really differentiate between a pinpoint and something as wide as the beam, so your RTE will look like a fairly big thing.
(this is the ladybird book level of explanation).
Range-wise it will look like a small thing, but that's often the way anyway.

 

[bbg]

I think the size becomes more clear as the boat get closer together?

 

[lw395]

I think the size becomes more clear as the boat get closer together?

1 degree at 5nm is 160m, so you are going to be indistinguishable from a hefty vessel.
but I expect your 6kt speed will give the game away.
I can see it being a nuisance close to the harbour entrance.

 

[Tidewaiter2]

I wouldn't say I'm an expert (because you're not paying me!), but
The ship's radar will be installed high enough to give a 10nm horizon
The 20 degree heel is close to where the RTE falls over, but you are not going to be heeling directly towards the ships you have CPA problems with.
The output power of the RTE is plenty to be seen.
I think it ought to work, but not having full information, the heel angle concerns me a little.
It would be interesting to have the conversation with the people who designed it.

Thanks for that, I'm thinking of an fitting an Echomax dualband in that location.
We have a Duoball at masthead, and the previous owner left us a Trilobe upgrade which he had not fitted, and we have not yet, but keep in a locker.

I think we have a fairly good radar signature in most weathers, because Jobourg Radio have called us up a couple of times, thinking we were a commercial out of station.
My main concern is the thick fog banks you hit off there and down to St Malo. Pre the Condor/trawler collision, I've had close ones with them in fog from Nab-St Malo and fastcats off Dover moving very fast in fog.

Another poster here mentioned the French regard it as illegal -anyone got a definite distance off and the legal regulation which applies?
I cannot believe they would outlaw a good radar signature in those waters?

 

[Conachair]

It's an interesting comment but I'm wondering how realistic it is. ........

Following on from previous post, the only log entry recording how much a ship changed course was from 70deg to 63deg(ships cog). On passage from Azores - UK. Doesn't say how long for. There are other entries of ships changing course but no mention of by how much.

One thing of interest is how often the log differs from memory, if you want to know what happened, read the log. Memory might not be as accurate as you like to think it is..

 

[Scotty_Tradewind]

Presumably in a T35, your real concern, is not being able to get out of the way quickly enough?

Ah but the mere fact that with radar, ais and the Active doo da means that I do hopefully stand a better chance than I would without them.

Our old Tradewind is definitely built for comfort and not speed and on our recent 5 month excursion we were often able to confidently sail in conditions that many lightweight speedy vessels skippers and crew would probably find more than challenging.

Ya pays yer money.........

S.

 

[Malabar]

The MAIB report into the OUZO accident included some detailed analysis of radar reflector performance. In general, passive radar reflectors are pretty pathetic. For radar auto detection and ARPA tracking you need continuity of return. An active responder e.g See Me etc gives you at least a fighting chance of being seen.

 

[Ric]

The MAIB report into the OUZO accident included some detailed analysis of radar reflector performance. In general, passive radar reflectors are pretty pathetic. For radar auto detection and ARPA tracking you need continuity of return. An active responder e.g See Me etc gives you at least a fighting chance of being seen.

I have tube static reflectors on my boat, and they do give a good return. I know this because whenever a large ship is heading for me rather than rather rudely asking them "have you seen me", I ask them "how big is my radar return". I thus get useful information from them, and don't risk offending them by implying they might not be paying attention.

Note that I have several reflectors - one on each shroud, and a third on my wind generator pole. At least one reflector is therefore always approximately vertical, whatever angle of roll of boat.

Tube reflectors only work if they are vertical - I see a lot of boats with just one mounted on a shroud (meaning tube is only effective on one tack) or worse on the backstay (meaning it is hardly effective at all)

 

[shaunksb]

I find no problem sailing without a reflector at all and the stats show very few boats ever being run down.

Just a thought.

Perhaps you don't do much night sailing but it's this or poor visiblity when they come into their own.

As someone has just said it would probably have made a big difference in the Ouzo case.




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[Topic]

Active Dual Band Reflectors

Most interesting story from OP. Having been told by Dover Coast Guard that my 13m aluminium motor cruiser had an intermittent echo, after I complained about a near miss, being waked by a ferry heading for Dover at 20 knots in less than 100m visibility, I have taken a keen interest in the preceding discussion. Echomax and Sea-Me both make dual band active reflectors at the somewhat eye-watering price of about £650. Anyone care to comment on service response or reliability from either company as technically the two units appear to be almost identical? I proceed in the dark and in fog and I would like to be seen by the big boys.

Thank you


Phillip Carr

TSDY TOPIC

Portland

 

[Georgio]

Tests have shown that the Echomax RTE (both the original single-band and the newer dual-band) gives a slightly better (more powerful?) response than the Sea-Me, however both work very well indeed and there is not much in it.

I fitted one of the first Echomax dual-band RTE's in the UK and it has performed faultlessly, including extended periods offshore when it was left on continuously.

I hope this helps.

 

[AntarcticPilot]

Tests have shown that the Echomax RTE (both the original single-band and the newer dual-band) gives a slightly better (more powerful?) response than the Sea-Me, however both work very well indeed and there is not much in it.

I fitted one of the first Echomax dual-band RTE's in the UK and it has performed faultlessly, including extended periods offshore when it was left on continuously.

I hope this helps.

I have a SeaMe, and it's difficult to see what service it could require! Barring an on-off switch and an LED that flashes when it is "painted" by a radar, there's no controls and nothing to fail. The LED provides evidence that there's a signal path from the black box to the antenna; there's no way you can monitor whether it is actually transmitting short of asking another radar equipped vessel.