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[dserrell]

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[edbuchanan]

Hi David,

Molly has a Plastimo "cylindrical" small sailboat radar reflector.  I attach it to our flag halyard with spring-type flag clips and hoist it up to the spreaders.  The radar reflectivity is unknown to me, but we put it up in fog as the best we can do.  Defender still sells them.

Ernie (Molly 23/II, 1984)

P.S.: this Saturday was one of the nicest Chesapeake sailing days we have had in some time: smooth seas, the boat was making a steady 5 knots, with very clear and cool weather.

[Craig Weis]

Yes but not the 'round' slab sided reflector, but a tubular one that sits above my starboard spreader. Suppose to have more reflective surface ares then the ball type. That's the selling point for me. I know it works by asking a passing freighter if he had a good hit? Came back, "thumbs up, 5 x 5" so I guess that means OK. The freighter was 'on my horizon', all direct line of site. skip. Picture in Frappr, I think. Picked it up at a vender's table at the All Sail Boat Show, Chicago about three or four years ago. Sail can not 'snag' on it and the reflector won't move about with the motion of the boat.

[edbuchanan]

Hi David,

Uh oh, it looks like my reflector won't do much good except on a radar hit directly in it's "sweet spot".  The radar cross section is ok, but if you look at the "dihedral corner" equation (fig. 1) for angular response at 32 degrees the reflectivity drops to 1/10 of the maximum value (useless).  I chose the dihedral version because the third plane (disks) are not much more than a wavelength.  Skip's result "might" be just some luck.  At 3GHz it probably does not work at all.

I tried treating the mast of my 23 like a cylinder reflector using the same equations and it is amazing how little it reflects.  The rigging probably reflects very little due to the stays being largely vertical.

Where did you sail in the Chesapeake?  We usually sail near Annapolis.

Ernie (Molly 23/II, 1984)

[edbuchanan]

Hi David,

I still have a Plastimo Octrahedral in the basement, it looks like it is time to get it back into action.  The tubular version was purchased with the thought  that it was more aerodynamic, always assembled and less of a slicing hazard.  My radar reflector is  run up the rigging only when it is foggy, as the bay is usually clear.

Wow, you were right on our normal stomping grounds.  It is a shame that I didn't see your boat at AYC as Com-Pacs are fairly rare.  Our boat was just across the draw bridge in Eastport.

This past weekend we saw a sizable boat approaching us with her crew waving wildly at us.  I couldn't figure out why they were so excited until I saw the Com-Pac logo on their sail.  It was a 35 and looking quite sharp, like a nice, proper ship.  A picture would have made a good advertising photo.

A similar event happened when we arrived back at our marina after a two week trip on the bay.  A man was smiling broadly at us and I figured he was just an overly enthusiastic dock hand.  No, he was a Com-Pac 23 owner who couldn't believe he was seeing a boat  just like his (a 1985?).  He and his wife were quite eager to see our boat as they cruise with children (same as us) and wanted to see how we were equipped for long trips.  They keep their boat in North Carolina.

Ernie (Molly 23/II, 1984)

[Craig Weis]

dserrell...I thought that the surfaces of the radar reflector shown in the picture posted are soppose to be not East-West-North-south but canted a bit. I think I read that some where. No 'flat surfaces'. I think I read that in Skunk Works.
This reflector pictured is anchored in a really neat bracket. Of course when she laid over it's canted. I guess it's no big deal.

By the way...how did you like that 1970 22' McGregor Venture. One is docked not far from me and has the 'look' of a fine shear and a really neat stern wrap-a-round tap rail using turned teak [?], pins. I don't know what to call the 'gingerbread'. She is molded in primrose yellow with white uppers.
skip.

[Craig Weis]

Thanks for the thought, yes Hunter's and then Macgregor's all of them are cheap 'rental type boats' and nobody cares too much what happens to them. Some models look good, some are so weird that they ought to be sunk on site, like the 26 footer. And water ballast??? But in there defence it gets the family out on the water for a day or week, and back with pocket change left. The taste of sailing I guess. Good place to start.
skip.

[Craig Weis]

skippy's R/F on the starboard spreader. Suppose to have more surface area then the 'ball' types...I don't know.