T&T: Radar Detectors at Sea

[Patrick And Margie Connor]

In reading some of the articles on short handed transits I got to thinking 
about using automobile radar detectors on boats to detect the radars on 
approaching commercial vessels.

There used to be companies that manufactured radar detectors for boats.  As 
I remember, these indicated a rough bearing (i.e. which quadrant) to the 
detected radar.  Also, these were fairly pricey.

I'm not suggesting using these automobile devices as a first line system on 
your boat.  Nor should they be counted on to replace good watch standing 
practices.  But, if you've got one in your car why not take it along on your 
next offshore/overnight transit and see how it does.

Without any real testing, here's what I think you might expect in the way of 
performance:

I think the frequency of commercial marine radars will fall into one of the 
operating bands of the automobile radar detectors (S, X, or K), i.e. it will 
detect them.  Police radars are doppler radars.  Most basic marine radars 
are probably simple pulse radars.  I still think the device will detect 
them.

It will have line-of-sight range.

If your vessel has a radar and it's operating, it won't work as the radar 
detector will be overwhelmed by your own radar.  On military vessels that 
have both radar and radar detectors, the radar sends a blanking pulse to the 
radar detector (ESM) when it transmits so the radar detector won't detect 
the vessel's own radar.

These devices will not provide any kind of reliable bearing information. 
The best you can hope for is an audible warning that will encourage you to 
scan the horizon

I'd be interested to know if anyone has experimented with these automobile 
radar detectors.  It might help to keep you awake on that next long watch.

Patrick Connor
"Cheers", Prairie 36
Fort Myers, FL