STEALTH

[Bergman]

Read a thing yesterday about radar reflectors.

Apparently yachts don't show up on radar and the funny shaped reflector that we hang in the rigging are invisible too.

The Euro-solution would appear to be having a reflector the size of Anglesey tied to the mast.

If yachts are not visible on radar why did the US government have to spend mega mega bucks on stealth aeroplanes?

Something here does not add up - or am I missing a trick?

 

[Guest]

Actually there was a test conducted in a boat mag last year [i think?] which used a bag of crumpled aluminium foil as a 'control' to measure the performance of the commercial radar reflectors and guess what - it outperformed most of them! So if all else fails in bad conditions, etc then nick your wife's cooking foil, scrunch it up, stick it in a bag and hang it up!

 

[AndrewB]

Yachts dont show up on radar when ...

... the watch-keeper is asleep. Blaming the radar at sea is like blaming the computer in the office - a useful scapegoat for ineptitude.

Radars on modern ships can practically spot a floating tin-can, let alone a yacht. Ask to go on the bridge next time you are on a cross-channel ferry, and you will see why the radar is the only navigational instrument the crew bother to use.

I've used several radars on yachts over the years, and even the cheapest and most basic will pick up a yacht with a reflector at 3 miles, though at worst this may drop to 1 mile in really bad weather. And having a decent reflector really does make a difference. When we go on club cruises, those with are much more visible on radar than those without.

Sorry for the rant, but there is a load of tosh talked about radars. The real problem is that some ships' officers get over-dependent on them.

 

[Guest]

Re: Yachts dont show up on radar when ...

I agree about the bit about the effectiveness of ship's radar. I was surprised just how sensitive they are. That said, I prefer to be proactive and use my radar to see what's out there rather than rely upon someone else using theirs.

Chris Enstone, Rival Spirit

 

[billmacfarlane]

There's an article about radar reflectors in this month's Sailing Today. Apparently the Firdell reflector isn't effective at at any angle from the horizontal and the company asked the orignal designer to come up with an improved design . It's out next month.

 

[davel]

Re: If the original designer was so good....

why didn't he design it right in the first place!!

 

[Guest]

I don't want to get too involved in differences of opinion here but a radar is a tool and the time when you want to be noticed on a big ships radar is when conditions are bad and when there is rain, spray, fog, mist, waves, etc (in other words water droplets in the air) a radar's effectiveness detiorates because water reflects radar waves and the radar automatically retunes or the guy watching it has to turn down the sensitivity and isolate all but the strongest echoes. Newer radars are far better at tuning out the 'clutter' but it doesn't mean all the ships are fitted with them! The main problem for a watchkeeper is tracking multiple targets - modern expensive radars will automatically track targets but if your echo is only on screen for less than 75% [say] of the time then you will be missed! Put this in perspective, I have been on the bridge of the 'Pride of Bilbao' and she is getting on a bit now and so is her equipment! They are really concerned with missing big ships and although [if they spot you] they will try and avoid you they do tend to rely on you keeping out of their way! So just assume you haven't been seen and stay out of their way and out of their channel especially when visibility is bad?

 

[vyv_cox]

I was working with a tanker chief engineer, also a yachtsman, last week. He told me that it is virtually impossible to see yachts on radar or by eye from his bridge. The tanker we were on was 25 years old, so it may well be that age of the equipment is a factor.

 

[AndrewD]

I've no personal experience, but two blue-water yachtsmen of my acqaintance (take a bow, Alan and Mike!) are convinced that radar reflectors are a waste of time. Both have had lengthy VHF conversations with large ships at close range who could NOT see them or their radar echoes. And these were big yachts - a 60-footer in one case. The only advice is to keep out of their way. Remember also, usually there is nobody actually on lookout, regardless of the ColRegs.

No sig is a good sig

 

[Guest]

A fishing mate marks his crab pots with home-made danbuoys using metre lengths of 1/4" aluminium pipe.

He reckons at night he can find them on his radar from about half a mile!!

As others have said "if they're not looking they won't see"!!

Ian D