I am about to buy a radar reflector ...

[Baggywrinkle]

... the question is which one? Small plastic sailing yacht 11.5m long with a 16m mast.

Do they work? What is your experience of liesure craft and radar? Do we show up?

Any recommendations would be greatly received. I've read some of the threads on the other forums and it all gets quite heated with much speculation so I hope I can get some objective advice straight from the horses mouth.

 

[Reverend Ludd]

Give one of these a look

See Me

 

[channel]

The radar reflector has its use but for me an AIS signal being put out by a small craft is far more effective. Most ships will have an alarm set for targets showing a CPA of less than 1 mile. It forces the watchkeeper to take action. Also ships will know your name and you theres.

 

[homa]

Firdel Blipper

Firdel blipper or equivalent. Retails at about £80'ish. Buy the mounting brackets and fix on the mast just above the spreaders.
I have one.
The Pilot cutters, RNLI and other professionals use them.
Basically the bigger the better for any passsive reflector.
The clear plastic toilet roll type IMHO are not worth the bother.

If I had the spare cash I'd buy a Seame, after that I'd probably get AIS.

AIS is excellent for what it is. But I don't even have an AIS receiver on my own boat.

We use radar and AIS all the time at work, but the AIS has its limitations. Very annoying when in congested waters and the AIS software gets overloaded. hence the need for good old fashioned reflector IMHO.

 

[Baggywrinkle]

Thx. for the answers.

Would love to buy everything I want now but got to prioritise.

Will probably get an Echomax 230 for the time being.

 

[AntarcticPilot]

The Ouzo report on the MAIB suggests that passive reflectors are little use in practical circumstances. An active transponder like the See-Me is much more likely to be seen.

An AIS Class B transponder is recommended by some, but big ship posters on here have suggested that a) AIS is still (IN THE MAIN!) a new system for big ships that is implemented in a minimalist way (this will slowly change as ships update bridge equipment) and b) that Radar is king in the wheelhouse. These has been confusion about filtering of returns; however, it does seem that any "dangerous" AIS target will always be flagged.

One thing to bear in mind about class B is that the update frequency is slow, so a ship might be relying on information sent by your vessel that is out of date.

 

[shaxi]

One thing to bear in mind about class B is that the update frequency is slow, so a ship might be relying on information sent by your vessel that is out of date.

i also dislike this , when you got the information ,you don't know if this is still valuable !

 

[Piers]

AIS is still (IN THE MAIN!) a new system for big ships that is implemented in a minimalist way

Hi AntarcticPilot,

Can I ask a question re AIS, please? From everything I've read, no AIS transmits speed through the water. Is this correct?

Since collision avoidance relies on sea-stabilised info (Speed through the water and ship's heading - not COG and SOG) surely the info cannot accurately be used for collission avoidance.

Am I barking up the wrong tree?

Piers

 

[AntarcticPilot]

Hi AntarcticPilot,

Can I ask a question re AIS, please? From everything I've read, no AIS transmits speed through the water. Is this correct?

Since collision avoidance relies on sea-stabilised info (Speed through the water and ship's heading - not COG and SOG) surely the info cannot accurately be used for collission avoidance.

Am I barking up the wrong tree?

Piers

AIS transmits exactly what it is told to! Speeds are often inverted (Ro-Ro ferries are prone to this - and I've been fooled by it!). I don't know whether what you say about speed is true; I suspect it is as the primary feed will be from the GPS. But any system should be able to allow for that using current information, so I doubt it matters in practice.

However, Thanks for your implied confidence in me, but I am no more an expert on the system that many other people on the forum - and far less than some!

 

[Piers]

Hi AntarcticPilot,

Thanks for the reponse. My apologies - I had thought you were literally a pilot (sea or air...) in the Antartic! Should have checked your profile....

All the best, and again, thanks for the heads up.

Piers

 

[lenseman]

In real desperation you could very loosely scrunch up a roll of Aluminum Baking Foil and gently stuff inside a pair of female tights and hoist aloft. It will be as good as most passive reflectors.

ps: Make very sure the female is not wearing them at the same time!

pps: Cheap too . . . . and I wasn't referring to the female!

 

[onesea]

My thoughts is it depends how much the OOW depends on setting up the radar...

If they are keen and trying they may see you, if not they will not...

I would not spend money on a radar reflector but a "see me" or AIS probably.

I do not know how slow class B AIS are but IF they see the target most OOW's will try and avoid it buy half a mile or more reasonably IF POSSIBLE.

Just be aware no matter what gear you have they might not notice you. Standards on bridges in equipment and expertise varies.

 

[KevinT1]

Firdell Blipper - internal corrosion ?

Apologies if this has already been covered elsewhere.

I'm advised that the Firdell Blipper I have fitted is prone to internal corrosion and that I should change it as it is now over 10years old.

Apparently the internal alloy plates are not protected and as it has drain hole in the bottom which allows moist air to be sucked in

Does anybody have any experience on this ?

 

[Uricanejack]

Many Many years ago I took part in an unofficial unscientific survey with a couple of friends who also worked on big boats and played on small ones.

We would call small vessels on VHF and ask what kind of radar reflector they had if any and how they hung it.. If we got an answer we just thanked them for the info. If they asked why we would tell them we were just curious about how they worked.

Our unofficial unscientific results were.

The Firdells were best. Picking them up at the furthest ranges.
A properly hung Radar Reflector was pretty good..
Incorrectly hung radar reflectors not so good.
No Radar reflectors. No data we just didn’t see em. Darwin’s theory suggests they will die out.

I have read articles suggesting the firdels have no real advantage but my observation is they do. No I’m not a share holder or sales rep..

The Correct way to hang the traditional Radar reflector is so it fills up with water when it rains..

A short explanation is radar is reflected well by materials which transmit electricity and poorly by materials which don’t. If you can remember doing reflections in physics at school you may remember something about angle of reflection and the angle of incidence which is pretty boring long winded way of saying round metal objects reflect most of the radar wave away from the scanner it came from and so do flat ones a anything other than 90 degree angle.

Most boats are made of plastic and are rather round. Even the metal bit are round and made of aluminium which does not conduct.

A Skip would be an ideal radar target but they don’t sail very well.

Human body’s are mostly water 90% or something like that. Water conducts. You are a better Radar reflector than you boat.

As you can see yacht designers and builders developed stealth technology long before the US military.

Where I currently live work and play. Firdels are not common. The traditional radar reflectors are commonly used and work well enough.
.
The advantage of the firdel is it has multiple reflectors at multiple angles inside the fender so is unaffected by angle of heel.. The traditional radar reflector works best at a specific angle. Heel the boat 45 degrees and you would be better to have hung it wrong.

As for AIS. If it beeps buzzes or makes other noises Its annoying so I turn that feature off. I don’t look at it much and if I did I need glasses to read small darkly lit led screens so I cant see it any way. If you are relying on AIS for your survival Darwin suggests your species will not make it.

I do look out the window. And I do look at the radar.

There used to be an add campaign about see and bee seem for motor bikes. I never did like the putting the reflective stuff on my leather jacket even if it was sensible but I do ride with my headlight on. And I always assume cars trucks busses are all driven by blind deaf drunken idiots who pay no attention to anything else on the road.. The same applies to big boats when I am in a little one..

Have good Nav lights a Radar reflector and a big bright torch to shine right in his eyes on the bridge without embarrassing him of course. And alter your of course if you have to. Darwin’s prediction should be favourable.

You were correct about the ground speed from the GPS and AIS. I expect there will be an AIS assisted collision some day I have not read of one yet but its inevitable. Most young navigators on big ships nowadays are very good with computers and gadgets and like to use GPS speed input to their Radars or ARPA. And don’t understand why this it dumb. They also set them to auto tune and auto clutter also dumb.
Makes the screen look pretty though. Unfortunately while this works well on a nice day. Its not so good on crappy days. If I remember UK weather. Crappy happens a lot..

 

[lenseman]

. . . . . Even the metal bit are round and made of aluminium which does not conduct. . . . . .

How amazing !!!

 

[cliff]

One thing to bear in mind about class B is that the update frequency is slow, so a ship might be relying on information sent by your vessel that is out of date.

Reporting intervals for Dynamic Data on AIS Class A units

Ship’s Manoeuvring Condition Nominal.....................................Reporting Interval
Ships at anchor or moored and not moving faster than 3 knots...3 minutes
Ships at anchor or moored and moving faster than 3 knots........10 seconds
Ship 0-14 knots................................................................10 seconds
Ship 0-14 knots and changing course.....................................3 1 / 3 seconds
Ship 14-23 knots...............................................................6 seconds
Ship 14-23 knots and changing course...................................2seconds
Ship >23 knots..................................................................2 seconds
Ship >23 knots changing course............................................2 seconds


Information included in the various message types is:
• Static information: Every 6 minutes and on request
– MMSI;
– IMO number (where available);
– Call sign & name;
– Length and beam;
– Type of ship; and
– Location of the position-fixing antenna on the ship (aft of bow/ port or starboard of centreline).
• Dynamic information: Dependant on speed and course alteration (see above)
– Ship’s position with accuracy indication and integrity status;
– Position time stamp (in UTC);
– Course over ground (COG);
– Speed over ground (SOG);
– Heading;
– Navigational status (e.g. at anchor, underway, aground etc. - this is input manually); and
– Rate of turn (where available).
• Voyage related information: Every 6 minutes, when
is data amended, or on request
– Ship’s draught;
– Hazardous cargo (type);
– Destination and ETA (at masters discretion); and
– Route plan (waypoints).
• Short safety-related messages:
– Free format text message - sent as required.

Dynamic data for AIS Class B units (message 18) is sent every 30 seconds if the speed over the ground (SOG) of the craft is greater than 2 knots or every 3 minutes if the SOG is equal to or less than 2 knots.
For both AIS Class A and AIS Class B static data is transmitted once every 6 minutes.

I don't see the speed of transmission on Class B units being a major issue for leisure sailors but there again I am sure some will think 30 seconds for updating is too long a time, I mean one can travel a long way in 30 seconds - I mean at 6 knots one could travel a whole 1/20 nm - (96.6m or approx 303' 9" or approx 101¼ yards)

 

[PilotWolf]

How amazing !!!

Worrying... I'm sure aluminum is electrical conductive and most of the rain catching types of reflectors are made of of it!

I would hazard a guess that most round metal things on boats are stainless steel...

W.