On Thu, 18 Dec 2003 17:40:10 -0800, "Lloyd Sumpter"
wrote:

Hi,

Considering buying a radar, so I have a few questions:

1. On a sailboat, where do you put the display? I rarely steer from behind the
wheel, mainly by sitting on one of the gunwales beside the wheel, or sometimes
by Otto while hiding from the rain under the dodger (hence the name... ).

When I installed the RL70CRC on Geoff's Endeavour 35, I mounted it on
a swivel mount he bought from Waste Marine made of anodized aluminum
so it could be swung around to the port side of the wheel, to view
from behind, or swung out over the cockpit table to view from either
of the lazarette seats. It was mounted with U clamps to the pedestal
vertical bars. Be sure to leave plenty of cable length so you don't
pull on the plugs. The only problem was the mount's locking knob
under the "table" of it came loose too easily. We broke the knob
trying to make it hold in heavy seas. It ended up lashed down in
heavy weather offshore to keep it from banging around.

2. Realistically, how far do you set the max range? I'm seeing that unless I
mount the antenna up the mast, I'm not gonna get more than maybe 10 miles range
no matter what unit I buy. Then again, if I see a freighter steaming at 30
knots, 10 miles away, I still have 20 minutes to do something. Is a 20-mile
range worth getting?

We use the 2KW radome to hold down the load on the house batteries for
long periods. When we moved it from the stern mounting pole, on the
Endeavour, about 20' off the water, to the Amel Sharki 41's mizzenmast
it moved up to double its original altitude. This reduces our MINIMUM
usable range, something I consider far more important than seeing that
freighter 30 miles away, especially when you are in pea soup fog. I
want to see that bouy on the screen until I can hear it clanking
around on its chain. At 40', I lose the bouy about 200 yards away,
which I guess is still OK. Don't go way up as you'll shoot right over
the close-in targets you're about to run over. But, don't go too low,
either, because you'll lose targets when you are in the trough between
swells higher than the radome.

On a sailboat, 2KW is plenty of power. Three mile range is plenty of
time to take evasive action when you're plodding along at sailboat
speeds. It also lets you see all the targets and use the MARPA to
track them, if you got it. MARPA works great for us. Once assigned a
target, MARPA watches him for us, alarming if he's going to get in the
way. I like the way it shows his course and speed over time, much
like a military radar I'm used to. 2KW from 40' up can see the shore
targets as far as you can see on a clear day, but in the fog. Of
course, with WAAS-GPS, using the radar to find your position becomes
pretty moot. I want to see that idiot in the center console fishing
boat and what he's doing, myself.

3. Do you trust yours enough to use it instead of a "watch" (ie watch the radar
screen instead of where you're going)? Trying to decide if getting a radar will
increase my cruising time significantly (ie more confidence in running at night)

No, it doesn't. Case in point is on my last trip from Florida on the
Endeavour 35 with one of the neighbors. We had used the radar all
night in pitch dark, under sail, about 80W off the GA coast, heading
the boat home to Charleston after Geoff left it in Daytona Beach.

The sun had risen and there were no targets on a beautiful morning in
a relatively smooth sea with little swell. We were only making about
3 knots, but didn't really care. No schedule is great. Breakfast was
on the cockpit table and we had just set down to eat. I looked up at
Lloyd to answer a question and this HUGE WOODEN SPOOL cable reel was
floating about 30 yards off the port beam! That thing must have been
30 feet across and 15 feet wide! It was HUGE!

I rushed to the radar screen as it went by and set the range to 1/8th
mile to see why it hadn't alarmed. There was NO RETURN WHATSOEVER
from this target from 30 yards off the port beam until I lost sight of
it behind us....not a single blip. There just wasn't enough metal
inside the wooden reel to show up on the radar.

While continuing breakfast, we both mused over the possibilities of
hitting that reel at 8 knots during the night after the moon went down
and you couldn't see past the nav lights on the bow. I got
goosebumps.

Radar can't see everything. It can only see radio reflections, not
wooden or absorptive obstructions.....like that thousand-pound cable
reel just floating around out there...

4. I see a "guard zone alarm" but no "constant-bearing alarm". Why not? wouldn't
a constant-bearing alarm be far more useful (and not that hard to implement)?

The guard zone alarms you to targets popping up in the guard zone.
MARPA, or whatever they call it on the other companies, tracks the
target for you, giving you course, speed, and watching to see it isn't
on a collision course with you. But, you must assign the target on
MARPA. It doesn't assign it automatically. If you think radar is
going to eliminate watches, you're barking up the wrong tree. It's an
AID, not a watch stander.

5. I'm looking at the Furuno 1623 or 1712, or the JRC 1000. I have a Furuno
GP-31 GPS and I'm impressed by the quality (also, probably 90% of commercial
boats around here have Furuno radars). Any comments?

Buy what you can get SERVICED, LOCALLY. I suspect they're all running
Furuno because someone is there to fix them and sells them locally.
Don't cheap-out or you'll regret it later. The most useful
electronics on Lionheart is the RL70CRC Plus Color radar-chartplotter
which overlays the radar right on the chart for us. It matches the
GPS position, already plotted for us on the chart display to the
returns the radar is seeing any time we're near land or known objects.
With it I can even tell you which side of the channel that fisherman
is anchored to because I can see him ON THE CHART. As soon as it was
installed, everyone quit using the GPS chart plotter in the Garmin
185. Geoff built a nice fiberglass console to mount this most-useful
display right in front of the helmsman's nose where the compass used
to be. It's THAT useful....(c;

6. Is it worth while to mount the antenna up the mast, or should I use a
"dedicated" mast at the transom?

Been on both, and it's a real tossup. The Endeavour was mounted on a
tilting mast on the transom. The tilt mechanism was useless as it was
hard to reach and hard to set. If you could pull a lanyard, instead
of screwing thumbscrews around, it might have been useful. The 2KW
radome antenna is a piece of circuit board with little antennas on it
rotated by the same motor a cassette player in your car uses by a
rubber belt. (I put a spare belt inside the radome before it was put
on the mast, by the way.) This antenna has a very wide vertical
beamwidth so it works fine even if heeled over 20 degrees. The new
mounting is fixed on the mizzenmast at about 40'. It can pick up
smaller targets further away, but loses them under the beam about 200
yards from the boat, where I used to see them down to the third finger
pier from ours on the dock. I wouldn't go above 40' for fear of
losing the close-in targets you're going to run into in the fog or
dark.

MAKE SURE ANYTHING IN THE WAY FORWARD of the radome is a long ways
from the radome. Lionheart has a big in-mast furling monster mast. I
can see targets disappearing at 000 relative, even though the masts
are 25' apart. If it were closer, we'd have a large blind spot where
it counts the most.


That's all for now...dreaming on a dull winter's day...

Go sailing with some various radars and play around with them before
you decide.

Larry

Larry W4CSC

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