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Subject: TWL: Radar Location
From: Bob Austin (thataway4@XXX.XXX)
Date: Fri Nov 01 2002 - 21:03:30 EST
On my Force 50 Ketch I had the Radar on the Mizzen mast. On the Cal 46
(cutter
rig) I had the Radar on top of a 9 foot Radar arch all of the way aft(About
13 feet off the water). On
this same arch were Ham antennas, GPS antennas, support for the 23 foot SSB
whip, brackets for two outboard motors, a davit which could be transfered to
either side and could lift up to 150 lbs (motor scooters or larger outboard
motors) , holder for stern anchor line (300 feet) and fishing rod holders.
With tens of thousands of miles under the keels of both of these boats there
was not significant "shadow" of the main mast on the radar. Boats move
around enough that a degree or two of obscuring target--if it even happens
is not significant.
As for tilting the Radar up or down--it should be horizontal with the
boats attitude at cruising speed. However most Marine Radar units have
about 25 degrees of vertical discrimination.
As for the resolution vs screen size: Yes the large Raster scan color units
may have better resolution--but the real issue is descrimination of
targets--and that is a function of scanner size--the larger the scanner the
better the descrimination. My personal experience is over 80,000 miles of
cruising with Radar--all with 7" screens. My close friend who has made
three circumnaviations--one without radar, to with has a 7" screen. The
ability to use and interput the image is more important than the screen
size. There are a few places where Radar is almost essential--heavy
fog--heavy traffic--night sailing etc. If you are really going to do
significant long distance cruising it is very worthwhile. If you are doing
what 95% of boaters do--not essential. If you can cruise for three months
for the price of a radar--20 years from now you will have been glad to have
taken the extra three months cruising.
Mounting the Radar on the fornt of the main mast is not wise (also what
about vessles comming from behind--if you are worried about shadows?) The
only proper way to mount a radar on the front side of the mast would be in a
SS tubular cage.
Incidently hearing a "snap" is not a good sound on a sailboat. Properly
tacked a boat drives off a little at first to get speed on the new
tack--watch the america's cup boats. Shock loading rigging slows boats
down/is hard on gear.
Regards,
Bob Austin
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