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... ).

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?

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)

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)?


What you need for this is a mode called "true motion". It requires a
good electronic compass or gyro fed to the radar. The picture on the
radar stays still and you move across the picture. When you reach the
edge of the screen it resets you to the bottom of the screen with a
new picture.
Other boats also move across the picture on the screen.

With this system you can put a cursor on another boat and your boat
can yaw or move anywhere and the cursor will remain at the same
azimuth that you set it at relative to your position. That will let
you see if the other boat is on coarse to you.

The MARPA systems in the small radars you have to manually acquire the
targets. Most are limited to around 6 targets that they will track at
one time. If you loose contact with a target for a time you have to
reacquire it again. It can become a pain to use. It sounds like an
ideal thing to have but in reality it is a lot of work to use.

The true motion though is very useful.

I have an older raytheon 21xx that has both in it.

Regards
Gary

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?

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

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

Lloyd Sumpter
"Far Cove" Catalina 36