"Larry W4CSC" wrote in message
...
On Mon, 1 Sep 2003 10:46:14 -0500, "Keith"
wrote:

Best cost / performance ratio would be one of the JRC black and white LCD
models. Furuno would be good in any model. Stay away from Raymarine,
they're
pretty much making only crap since breaking away from Raytheon.

I'm interested in why you know Raymarine is crap. My buddy's boat has
the SL70CRCPlus, 2KW radome, gyrocompass, WAAS-GPS in its multi-vendor
network I installed and the only problem we had was some water in the
radome which Raymarine simply gave us a new one, no questions asked,
to replace it. The units functioned flawlessly at sea and I've
recommended them to other boaters from our experience. Even with the
little 2KW planar stripline antenna array, I can see ships far beyond
the 24 mile range advertised. The MARPA is like having military
target acquisition and ranging and makes a helluva great toy during
long watches at night....(c;

How high is that antenna mounted? It would have to be 70' up to have a
horizon at 12 miles. If it was mounted that high you would only be able to
see ships higher than 70' at 24 miles. Those would have to be some pretty
big ships for you to see them at ranges of well over 24 miles, no matter how
powerful the radar.

Ed

On Fri, 05 Sep 2003 03:16:26 GMT, "Ed Kelly"
wrote:

How high is that antenna mounted? It would have to be 70' up to have a
horizon at 12 miles. If it was mounted that high you would only be able to
see ships higher than 70' at 24 miles. Those would have to be some pretty
big ships for you to see them at ranges of well over 24 miles, no matter how
powerful the radar.

Ed

Antenna's up about 45'. Radio horizon is further than your visual
horizon and can be extended by temperature inversions. The other
thing to consider is the height of the target. A radar reflector a
hundred feet above the water or a large ship can be seen way further
than the horizon because he sticks up OVER it for quite a distance.



Larry

Extremely intelligent life must exist in the universe.
You can tell because they never tried to contact us.

Thanks for the help all, I am leading towards Furuno.

Jim, you hit the nail on the head with your statement. The wife and myself
will want to know 'radar' inside and out before the purchase and install.

I know what you mean, between the death grip on the wheel, one eye on the
GPS and the other squinting forward through the fog I really don't need
another screen to look at...

"Jim Woodward" wrote in message
om...
An heretical question -- are you really sure you want a radar?

I should say that I'm no Luddite -- when we finish with Fintry, she'll
have two radars, a 12kw, six foot Furuno and a small Koden backup, but
my wife and I are both experienced radar operators and our passages
are generally long enough so that our watchkeepers get some training
in the basics. But using radar on a relatively large, stable boat,
with autopilot, and often two operators in the wheelhouse is very
different from driving a small boat with one hand and eye and trying
to make sense of a lot of targets on a small screen with the other.

I would say fairly strongly that you can't operate a radar in Cape Cod
Bay and drive the boat at the same time. There are too many targets
-- boats, bouys, fishing floats with reflectors, a few ships, and so
forth. Each of them requires separate attention to figure out whether
it's a danger or not, and on a small radar, with only two electronic
bearing lines, that means you have to keep a mental picture of what
you've looked at and what you haven't.

So, unless you're perfectly comfortable with dividing the two jobs --
driving and radar operator -- and handing one off to someone else,
think twice about the radar. I'm based in Boston and learned to sail
down East, so I do understand how white your knuckles can get in fog,
but you can minimize risk by staying on the edge of the channels,
stopping and listening every few minutes, and watching carefully.

If you think you're going to go ahead with the radar, get someone to
take you out with a radar and actually use it for a few hours. Best
to do this on a clear day, so you can compare the radar picture to the
visual. This is the best way to understand that it doesn't tell you
much except that there's something there. I'd volunteer for this, but
Fintry's still in England and doesn't have an engine at the moment, so
you'd have to wait 'til next summer.

As for brands, go the Newport Boat Show (9/11-9/14) and play with the
major brands (Simrad, Raymarine, Furuno, Koden/Sitex, JRC). I would
discount most of the talk of quality differences as Ford versus Chevy
and pick the one that seems the most logical to you. The Koden on
Fintry was purchased by her former owner (the Royal Navy), so I didn't
choose it, but it works perfectly well. While we chose a Furuno for
our big radar for Fintry, we took a Raytheon around the world on
Swee****er, and I like the JRC in the mid range. Simrad is very
interesting and has a different user interface. I haven't looked at
the size you'll need.

Make sure your mount gets the beam above everyone on the boat all the
time -- there's enough microwave energy there to pay attention. This
means you'll probably need an arch, as it will weigh less than a pole.
Put your white running light up there, too, above the radar.

Jim Woodward
www.mvfintry.com

"Wheres the sun?" wrote in message
news:fiJ4b.322150$o%2.146075@sccrnsc02...
I own a 24' Chapparal Signature Series cruiser and enjoy weekend trips
from
Boston down the coast to Cape Cod.

A few weeks ago I found myself caught in the worst fog I have ever
encountered, right down to the water, I could barely make out my pulpit.
Thank god for my Garmin 232 GPS to make it home. My fingernails were dug
deeply into the steering wheel as we continously listened to the Harbor
Cruise ships' horns alerting us of their presence, we finally made it
back
in one piece.

Can someone recommend a decent radar system for my boat. I do not have
an
arch so installation tips would be appreciated as well.

Thanks in advance!

"Larry W4CSC" wrote in message
...
On Fri, 05 Sep 2003 03:16:26 GMT, "Ed Kelly"
wrote:

How high is that antenna mounted? It would have to be 70' up to have a
horizon at 12 miles. If it was mounted that high you would only be able
to
see ships higher than 70' at 24 miles. Those would have to be some pretty
big ships for you to see them at ranges of well over 24 miles, no matter
how
powerful the radar.

Ed

Antenna's up about 45'. Radio horizon is further than your visual
horizon and can be extended by temperature inversions. The other
thing to consider is the height of the target. A radar reflector a
hundred feet above the water or a large ship can be seen way further
than the horizon because he sticks up OVER it for quite a distance.



I was using a radio horizon calculator to get those numbers. 45' gives you a
9 mile horizon. That means that (ignoring anomalies caused by atmospheric
conditions) that to see a target at 24 miles it needs to be 120' tall. I'm
not arguing that you can't see 24 miles with that 2KW radar - in fact a 12
KW radar would not be able to see any further than your radar given the same
conditions. Many people seem to think a higher power radar will allow them
to "see" further, while they are really constrained by geometry rather than
power. What the higher power will do is give you better discrimination (they
will see targets that you cannot)..

Ed

On Sat, 06 Sep 2003 02:49:20 GMT, "Ed Kelly"
wrote:


I was using a radio horizon calculator to get those numbers. 45' gives you a
9 mile horizon. That means that (ignoring anomalies caused by atmospheric
conditions) that to see a target at 24 miles it needs to be 120' tall. I'm
not arguing that you can't see 24 miles with that 2KW radar - in fact a 12
KW radar would not be able to see any further than your radar given the same
conditions. Many people seem to think a higher power radar will allow them
to "see" further, while they are really constrained by geometry rather than
power. What the higher power will do is give you better discrimination (they
will see targets that you cannot)..

Ed

Actually, what's MOST important is how CLOSE the radar can "see", in
the fog or in the dark. On the old boat, the 2KW Raymarine dome was
mounted about 15' off the water on a stern pole mount. On the 1/8th
mile range, I could see the masts of boats about 6 slips away, at the
edge of the transmitter's main bang. I think that's very nice when
you're feeling for that bouy in a fog bank or trying to avoid the
idiots fishing in the dark with no lights on.....

Moving it up to 45' has cost us about 4 slips because the bottom of
the radome is supposed to protect us from the radiation, probably
something some government bureaucrat dreamed up to make himself a job.
From a 2KW peak power radar with a piece of printed circuit board for
an antenna? How stupid. Well, nothing I can do about it. The deck
on the Amel Sharpi is covered with sails from the bow way past the
stern....(c;


Larry

Extremely intelligent life must exist in the universe.
You can tell because they never tried to contact us.

"Jim Woodward" wrote in message I would say
fairly strongly that you can't operate a radar in Cape Cod
Bay and drive the boat at the same time. There are too many targets
-- boats, bouys, fishing floats with reflectors, a few ships, and so
forth.

I'd say that depends entirely on your own individual ability to multitask
and set priority. Frankly, the workload you describe there is very low
compared to what the human brain can cope with when trained and practised
(try flying an airline into fog-bound La Guardia on a Friday night!). Marine
radar is so easy to use (only two dimensions) and boats move relatively
slowly and you can slow down and even stop in a boat.

"Bill Andersen" wrote in message
news:mGJ4b.38235$nf3.23356@fed1read07...
I spent a lot of time shopping for radar a few months ago. I was on a
budget

I have a Furuno 1622 and yes it has proved totally reliable over two years.
My only gripe with it is that the waypoint lollipop keeps coming and going,
or appeariing in totally the wrong direction. Furuno blame the (Raymarine)
GPS for providing corrupted NMEA information. Raymarine blame Furuno.

Yes, but the airliner has an autopilot -- nobody is actually steering
it, which was part of my point -- you can do this on a large, stable,
vessel with an autopilot, but not on a small boat. And on the
airliner, you have two pilots, an air traffic controller, and there
are rules which pretty much everyone follows. And, finally, the
controller that's guiding the airliner is on the ground and has full
automatic radar plotting in three dimensions, so that every target is
shown with course, speed and altitude. The small boat radar doesn't
do automatic plotting and can do only two manual plots at a time on
screen.

Driving a small boat in Cape Cod Bay is a lot like driving a car in
heavy city traffic. For starters, there are lobster pot buoys every
100 feet or so that you have to dodge (the big boat throws them to the
side -- the small boat picks them up in the outdrive). Then you want
to keep on course. There's a fair amount of traffic, and unlike on
the city streets, it's not all moving in more or less predictable
ways, and, in the fog, you can't see any of it. And so forth.

Of course, I see people on the highway who drive and read the
newspaper at the same time. May they live long and prosper, but I
don't want them near me.....

Jim Woodward
www.mvfintry.com


"Ric" wrote in message ...
"Jim Woodward" wrote in message I would say
fairly strongly that you can't operate a radar in Cape Cod
Bay and drive the boat at the same time. There are too many targets
-- boats, bouys, fishing floats with reflectors, a few ships, and so
forth.

I'd say that depends entirely on your own individual ability to multitask
and set priority. Frankly, the workload you describe there is very low
compared to what the human brain can cope with when trained and practised
(try flying an airline into fog-bound La Guardia on a Friday night!). Marine
radar is so easy to use (only two dimensions) and boats move relatively
slowly and you can slow down and even stop in a boat.

"Jim Woodward" wrote in message
om...
Yes, but the airliner has an autopilot -- nobody is actually steering
it, which was part of my point -- you can do this on a large, stable,
vessel with an autopilot, but not on a small boat. And on the
airliner, you have two pilots, an air traffic controller, and there
are rules which pretty much everyone follows. And, finally, the
controller that's guiding the airliner is on the ground and has full
automatic radar plotting in three dimensions, so that every target is
shown with course, speed and altitude. The small boat radar doesn't
do automatic plotting and can do only two manual plots at a time on
screen.

What you describe above is actually rarely the case. I'm an airline pilot,
and the workload even with modern aircraft is still much higher than on my
boat. On older aircraft, or with military aircraft, there is simply no
comparison. But the point I'm making is not just to argue which is the
harder to manage, a boat or a plane, but it is simply that you can adapt to
higher workloads as you get more experience. What is a high workload to
somebody with little experience of a high workload cockpit is a cakewalk to
somebody who has done it for a while.

Ric:

We may need to agree to disagree, but I'll take one more shot at it.

I think that when driving a small boat in heavy fog, dodging lobster
buoys, and other traffic, you can't take your attention away from the
wheel for more than a second or two any more than you can read the
newspaper when driving sixty on the highway.

Suppose you're on final in fairly choppy weather in a plane without
automatic landing and there's no one in the right hand seat. Can you
really do anything besides land the plane?

No? Not because you don't have spare brain capacity, or even a spare
hand, but because your visual attention has to be focused on the
runway.

Now, as you pointed out, this isn't a completely fair analogy -- the
small boater can stop, pay attention to the radar for a few minutes,
and then start again. However, few people will actually do this -- it
takes too long to get where you're going.

I want to ask a couple of questions -- please don't take offense, none
is meant ---

1) How much experience do you have in small boats in heavy fog?
2) ... where there are pot buoys all over?
3) ... where there's a lot of traffic of all sizes, even on foggy
days?
4) ... with small boat radars?

By small boats, I mean 24' or so, with an outboard or outdrive, so
that the steering is inherently unstable -- it tends to yaw if not
tended all the time. By small boat radar, I mean basic -- no ARPA,
just two electronic bearing lines and two adjustable range rings, and
a seven inch display. By a lot of trafffic, I mean twenty or more
boats and ships that would be in sight if it weren't for the fog.

I ask because there aren't too many places in the USA where you get
heavy fog, many pot bouys, and lots of traffic and just as I can't
really speak to the workload of a commercial pilot, one who hasn't
been here can't speak as well to the challenge we're discussing.

Regards,

Jim Woodward
www.mvfintry.com

"Ric" wrote in message ...
"Jim Woodward" wrote in message
om...
Yes, but the airliner has an autopilot -- nobody is actually steering
it, which was part of my point -- you can do this on a large, stable,
vessel with an autopilot, but not on a small boat. And on the
airliner, you have two pilots, an air traffic controller, and there
are rules which pretty much everyone follows. And, finally, the
controller that's guiding the airliner is on the ground and has full
automatic radar plotting in three dimensions, so that every target is
shown with course, speed and altitude. The small boat radar doesn't
do automatic plotting and can do only two manual plots at a time on
screen.

What you describe above is actually rarely the case. I'm an airline pilot,
and the workload even with modern aircraft is still much higher than on my
boat. On older aircraft, or with military aircraft, there is simply no
comparison. But the point I'm making is not just to argue which is the
harder to manage, a boat or a plane, but it is simply that you can adapt to
higher workloads as you get more experience. What is a high workload to
somebody with little experience of a high workload cockpit is a cakewalk to
somebody who has done it for a while.