[Paddlewise] Kayak Radar visibility

Jack Martin wrote some interesting stuff about radar reflectors.

There have been a series of articles on the subject recently in Practical Boat
Owner magazine. During the course of the articles a number of commercial passive
reflectors were tested on a sailing yacht for radar visibility from a large
commercial power vessel - the conclusions as far as I recall were that these
passive reflectors at best made virtually no improvement to the radar reflection
of the yacht, and in several cases actually reduced the reflection. This caused
some consternation, and the reflectors were taken to a military radar test
facility, where it was found that in certain circumstances they could cause
interference which cancelled radar reflections from the yacht itself!

I would guess that if a reflector up a 50ft mast doesn't help, its not going to do
much on a kayak/paddler which is completely (at least from sea level) obscured
when  sitting in the trough of waves bigger than say 3-4 ft. Stealth kayak! -  I
would assume that you are invisible to the eyes and radar (if anyone is actually
looking at it) of other craft.

I personally don't have much concern about being run down by commercial vessels
(kayaks are pretty much the only craft which tend/are capable of nosing around/in
the local sea cliffs where I do maybe 90% of my paddling). However, I wonder
whether some sort of active transponder would give kayaks a noticeable radar
signature. As a research student I spent some time at a wildlife field station
radio tracking deer. At this time (~1990) active radar transponders were being
tested for wildlife telemetry/tracking. Units were fitted to pink footed geese.
Geese obviously swan (sic) around somewhat higher above the water than kayaks (at
least those which aren't equipped by inflatable crotch dirigibles) but as far as I
remember you could follow geese fitted with transponders around quite effectively
(at least when they were airborne) over the range of a standard marine radar
outfit. GPS/satellite transponders came on the scene about the same time for
wildlife telemetry and I haven't heard anything more about the use of radar, but
the units were obviously relatively small and light if they could be carried by
birds (I assume <5% of the body weight of a goose)- presumably because most of the
weight would be the battery, which can be relatively small because the unit only
transmits when it receives incoming radar.

This may have already been tried on kayaks/boats, I don't know, but food for
thought.

Cheers

Colin Calder
57º19'N  2º10'W






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