Radar - what you see.- or don't!

[Guest]

Radar - what you see.- or don\'t!

I have recently installed a Raytheon SG72. It was extremely interesting to see what could and could not be seen.

A 25 foot motor boat of the Binliner variety did not register at all bows on, and only showed a good echo when broadside on. The wake the boat made showed up better than the boat!

A small launching trolley on the beach had a clear echo

A contessa 32 with no radar reflector could not be seen until abeam 45 degrees.

All the yatchts on the moorings nearby (all with radar reflectors), and head on had very sharp reflections.

The small channel bouys were visible but came and went

Perhaps radar reflectors do work.

 

[Guest]

Had you not heard, contessas are .............

fitted with stealth technology, It is the wake of a binliner that does the most damage, so it is far more important to keep any eye on that! Now try the same exercise, in driving rain and a force 6. then turn of the toys and revert to Mk1 eyeball's. You see, they saw it all, and your radar did not!

 

[Guest]

Stealth Contessas

So I've wasted my money then! The Mate wanted the radar after all the ships we didn't see in a channel fog. I wanted to put a furling jib on - I lost!

 

[Guest]

Mate foresail...........................

Sell the Mate, and buy the fore sail, much more use than Radar, after all, you did not hit any of these ships, did you, and what is the point in spending all that money watching things you cant see? If in doubt, a radio call stating your possition and asking if they can see you is much more effective. I have found, that if you do that, one of them will tell you how many of them there are, and which if any are likely to give you a problem. This also has the advantage, of letting them know you are there if they had not spotted you on their Radar.......essential if you have a Contessa dont ya think.

 

[Guest]

Re: But Wait

Chris,

Don't lose heart too soon. It takes half a season to get used to the radar and then you'll love it.

You have to get the book out and twiddle a few knobs, especially if its an LCD set. After that you can safely head for the ship infested fog bound areas at full speed with only one pair of pants. You'll be glad that you left your new sail until next year then.

Gary

 

[Guest]

Radar +\'s & -\'s

A really big radar reflector would be (a lot) cheaper, lighter, have less windage, use (a lot) less battery, and be less likely to break down than a radar dome + normal size radar reflector up the mast.

Not so much fun, though.

Signed An owner of a stealthy Contessa

 

[Guest]

Re: Radar +\'s & -\'s

I seem to remember an article in YM that concluded that passive radar reflectors were virtually useless.

I also remember vividly sitting on a mooring in the Orwell watching a ferry coming up the river and being completely unable to find him on the radar, despite the bouys being clearly visible on screen.

Don't know the answer, maybe the operator makes a lot of difference. There were lots of knobs and switches on the machine - perhaps they should have been twiddled in a different order

Is practise the answer?

 

[Guest]

If you don\'t see them - why worry

My mate doesn't go allong with this theory.

After several foggy crossings, and listening to the frightening tales of close encounters from the people with radar, we had not seen or heard a single ship so had totally stress free crossings.

I can't bear to think of all that electricity being used to power it! (mean Scotsman by decent)

Still - I've got the thing now and the mates happy - now to get her to actually come on the boat!

 

[Guest]

Re: Radar - what you see.- or don\'t!

A few key elements are missing from your post: height of the scanner, range on which the radar was set and distances at which the visual sightings took place. I have noticed on my Furuno 1621 that targets 2 miles away show much better on the 2 miles range than on the 4 miles range and that they are next to invisble on the 8 miles range. If you scanner is too high, the sea clutter return will be much stronger so that the nearby buoys will be less visible. john

 

[Guest]

Re: Radar - what you see.- or don\'t!

John the scanner is mounted on the mizzen - I would guess about 5 mtr above the sea - the range was 1/4 to 1/2 a mile.

 

[Guest]

True story about a happening in fog.

Told to me by the tutor when I took my VHFDSC. He and one other were acting as lookouts on deck in very thick fog on a yacht which was I believe was on route from France to Cornwall. They had radar running and it did not show any boats or rather dangers near them, there was no noise other than their own boat, and yet as they were talking a lit cigarette end fell from above and landed on the deck between them. No one on board smoked. so hmmmmmm....

Dave Beckett

 

[Guest]

Re: Radar - what you see.- or don\'t!

Mine's on a post about 3 meters above water (check pictures of Vendee Globe and other boats to see at what height they have theirs). AT a range of 1/2 nm, I had the entrance of Rye harbour (in New hampjire, USA ...) completely masked by the returns of lobstdr pots floats (they were acting like the "chaff" thrown by allied bombers in WW II to confuse German radar.... Methinks you should get somebody who's expeerienced in radar to look at yours (poor tuningor something like that) john

 

[Guest]

If only you\'d bought the RL72

nm