On Sun, 23 Nov 2003 23:44:10 +0000, Rodney Myrvaagnes wrote:

On Sun, 23 Nov 2003 15:54:00 -0800, "Lloyd Sumpter" wrote:



Thanks for the input!

I didn't mean an either/or scenario - it's more like: if I have
GPS/sounder/charts, what extra does radar give me? And of course, it DOES show
vessels, etc., but I'm thinking that's mainly a consideration in fog, and I'm
wondering if I would venture out even if I HAD radar (after all, what if the
radar quits?).

So is radar worth it for the 1 day a year I MIGHT venture out in fog?

Or, to put it differently, what ELSE is radar good for? Can I use it to
determine if a freighter 10 miles away is on a collision course with me? Do
others normally run with radar on, even if it's clear? Why?


That is actually a different question, because a radar has value for measurement
even when you can see.

Example 1: If you need to anchor in a confined space, and the obstructions all
show on the radar, you can maximize your scope by finding the center of a range
circle that just kisses the three nearest obstructions.

2) Your chart shows you the safe distance from a headland. You put a circle of
that radius on the screen. and steer so it doesn't intersect.

3) When you see a ship, you can put a bearing line on it and a range circle. If
the ship comes inside the circle without moving off the bearing line you need to
take action.

In general, you will find that an accurate plan view of the surroundings is a
valuable supplement to eyeballs.



All Great Information - thanks everyone!

A couple of points I see that I hadn't seen before. One is night: I do
occasionally sail at night, and it would be great to see the boats/ships rather
than squinting at little lights (esp if they're towing things, which is very
popular here on the coast. Anybody know if radar could pick up a log-boom?)

Also, measuring distance from objects. Good point. Last time I was out, I needed
to clear some rocks before making my turn - GPS is OK for that, but radar would
have made it easier.

And the point about practice I already thought about: If I'm only using it a few
times a year, thick fog is NOT the place to figure out how it works!

Final question: if the fog was thick (vis. maybe 100 ft) and you had radar (and
GPS, etc) would you go out?

Lloyd Sumpter
"Far Cove" Catalina 36

On Mon, 24 Nov 2003 06:51:32 -0800, "Lloyd Sumpter"
wrote (with possible editing):

....snip

Final question: if the fog was thick (vis. maybe 100 ft) and you had radar (and
GPS, etc) would you go out?

I'm drawing on experience from more than 30 years ago, when my boat (a
38' Hubert Johnson m/v) had loran and radar only, GPS wasn't yet
around: No, I wouldn't unless it was some kind of emergency and then
I'd be damn careful and proceed slowly. Why look for trouble?
--

Larry
Email to rapp at lmr dot com

On Mon, 24 Nov 2003 06:51:32 -0800, "Lloyd Sumpter"
wrote (with possible editing):

....snip

Final question: if the fog was thick (vis. maybe 100 ft) and you had radar (and
GPS, etc) would you go out?

I'm drawing on experience from more than 30 years ago, when my boat (a
38' Hubert Johnson m/v) had loran and radar only, GPS wasn't yet
around: No, I wouldn't unless it was some kind of emergency and then
I'd be damn careful and proceed slowly. Why look for trouble?
--

Larry
Email to rapp at lmr dot com

"Lloyd Sumpter" wrote in message
Final question: if the fog was thick (vis. maybe 100 ft) and you had radar
(and
GPS, etc) would you go out?


In New England, especially Down East, that's not a good question. Since fog is
dependent on the water temperature, its quite common for harbors to be clear,
while the fog lurks just off shore, waiting to be brought in by the tide.
Casting off means accepting a fair chance of running into thick stuff.

The first time I took my wife to Maine we got socked in at Jewell Island (the
outer island of Casco Bay) in fog so thick we only got occasional glimpses of
the boat anchored next in front of us for four days. Although we had radar, I
had never used it and didn't think it prudent to learn there. For a day or two
it was romantic, then my wife started complaining that she didn't want to spend
the entire vacation there when LL Bean was only 6 miles away. We discovered,
when we got up the nerve to poke out a bit, the we were actually on the inner
edge of a bank, and the fog had never made it to the inner parts of Casco Bay.
After that, we learned how to have faith in the radar.

So the answer is, while we might decide to wait for a morning fog to burn off,
we won't be held hostage by it.


--
-jeff www.sv-loki.com
If you can't say something nice, say something surrealistic. -Zippy

"Lloyd Sumpter" wrote in message
Final question: if the fog was thick (vis. maybe 100 ft) and you had radar
(and
GPS, etc) would you go out?


In New England, especially Down East, that's not a good question. Since fog is
dependent on the water temperature, its quite common for harbors to be clear,
while the fog lurks just off shore, waiting to be brought in by the tide.
Casting off means accepting a fair chance of running into thick stuff.

The first time I took my wife to Maine we got socked in at Jewell Island (the
outer island of Casco Bay) in fog so thick we only got occasional glimpses of
the boat anchored next in front of us for four days. Although we had radar, I
had never used it and didn't think it prudent to learn there. For a day or two
it was romantic, then my wife started complaining that she didn't want to spend
the entire vacation there when LL Bean was only 6 miles away. We discovered,
when we got up the nerve to poke out a bit, the we were actually on the inner
edge of a bank, and the fog had never made it to the inner parts of Casco Bay.
After that, we learned how to have faith in the radar.

So the answer is, while we might decide to wait for a morning fog to burn off,
we won't be held hostage by it.


--
-jeff www.sv-loki.com
If you can't say something nice, say something surrealistic. -Zippy

In article ,
"Lloyd Sumpter" wrote:

Hi,

Thinking of getting radar for Far Cove, mainly for this planned trip to
WCVI,
which has lots of fog.

Now, I've survived 20+ years of sailing Georgia Strait, etc. without
radar.
If it's really foggy, I just stay put. If I venture out, I use several nav
aids
including GPS to determine my position, blow my horn and listen.

I'm thinking that, even WITH radar, I wouldn't venture out in unfamiliar
waters in dense fog. And if I was out and the fog rolled in on me, I would
think
that GPS, sounder and a good chart would be better to find that anchorage
than
radar, assuming I could see at least 100 ft or so.

Comments?

Also, if I mount the radome on a post at the stern like most seem to,
doesn't
the mast and sail interfere with it looking forward?

Lloyd Sumpter
"Far Cove" Catalina 36


Back in the "Old Days", before GPS and Loran C, radars were used to
Navigate and Position Fix. In todays Modern Wheelhouse, GPS has taken
over the Position fixing duties, and a radar is used mainly to, "Keep
you from bumping into things that move around" Chart Plotters and
Good Watchstanding should keep you from "Hitting things that don't move",
but a good radar gives the watchstander "Electronic Eyes" that
can see thru snow, fog and night, and allow navigation in any NonVisual
situation.

Bruce in alaska
--
add a 2 before @

In article ,
"Lloyd Sumpter" wrote:

Hi,

Thinking of getting radar for Far Cove, mainly for this planned trip to
WCVI,
which has lots of fog.

Now, I've survived 20+ years of sailing Georgia Strait, etc. without
radar.
If it's really foggy, I just stay put. If I venture out, I use several nav
aids
including GPS to determine my position, blow my horn and listen.

I'm thinking that, even WITH radar, I wouldn't venture out in unfamiliar
waters in dense fog. And if I was out and the fog rolled in on me, I would
think
that GPS, sounder and a good chart would be better to find that anchorage
than
radar, assuming I could see at least 100 ft or so.

Comments?

Also, if I mount the radome on a post at the stern like most seem to,
doesn't
the mast and sail interfere with it looking forward?

Lloyd Sumpter
"Far Cove" Catalina 36


Back in the "Old Days", before GPS and Loran C, radars were used to
Navigate and Position Fix. In todays Modern Wheelhouse, GPS has taken
over the Position fixing duties, and a radar is used mainly to, "Keep
you from bumping into things that move around" Chart Plotters and
Good Watchstanding should keep you from "Hitting things that don't move",
but a good radar gives the watchstander "Electronic Eyes" that
can see thru snow, fog and night, and allow navigation in any NonVisual
situation.

Bruce in alaska
--
add a 2 before @

In article ,
"Jeff Morris" wrote:

I often keep it in standby to save power and
magnetron time (they do wear out)

Just a point of note here. Leaving the radar in standby on most
civilian consumer radars does not save anything on Magnitron
Time. What wears out is the Filiment (heater) and that is
always ON whenever the Powersupply is on, even in Standby Mode.
To convise yourself of this, do this simple test. When you first
"Fire up" your radar, there is a timer that allows the Magnitron
to "Heat up and Stabalize", usually for three (3) minutes or so.
After that initial "Warm up Period", when going from "Standby"
to "Operate" does your radar require another "Warm up Period"?
If so, then you are correct on your Magnitron time statement.(Not very
likely to be this way) If not, then then "Standby" only save you
Transmit Power, and that's not really very much in most cases.
Most modern Magnitrons have between 2000 and 4000 hours of Service
Life and that is Filiment Life, really.

Bruce in alaska
--
add a 2 before @

In article ,
"Jeff Morris" wrote:

I often keep it in standby to save power and
magnetron time (they do wear out)

Just a point of note here. Leaving the radar in standby on most
civilian consumer radars does not save anything on Magnitron
Time. What wears out is the Filiment (heater) and that is
always ON whenever the Powersupply is on, even in Standby Mode.
To convise yourself of this, do this simple test. When you first
"Fire up" your radar, there is a timer that allows the Magnitron
to "Heat up and Stabalize", usually for three (3) minutes or so.
After that initial "Warm up Period", when going from "Standby"
to "Operate" does your radar require another "Warm up Period"?
If so, then you are correct on your Magnitron time statement.(Not very
likely to be this way) If not, then then "Standby" only save you
Transmit Power, and that's not really very much in most cases.
Most modern Magnitrons have between 2000 and 4000 hours of Service
Life and that is Filiment Life, really.

Bruce in alaska
--
add a 2 before @

I was curious about this issue, so I sent a query to RayMarine a couple of years
ago. Here's what I asked, with reference to a SL72 radar:

I am curious as to the lifetime of the magnetron, or any other related
components. I often leave the radar in Standby Mode to save power and magnetron
wear, but have been advised that the magnetron is heated in standby and thus can
wear out. How many hours use might I expect, and will standby reduce wear?

Here's the response I received:

The magnetron is being heated anytime the radar is in standby. This will not,
however, significantly impact the life of the magnetron. Actual transmit time
is what really wears out the magnetron. If you are really concerned about it,
you can turn off the radar scanner by holding the CLEAR key in for about 10
seconds. this leaves the display energized, and available for the display of
chart or data. You can turn the scanner back on at anytime by tapping the POWER
key while on the radar mode. You will have to wait 70 seconds for the warmup
sequence to complete. In an EMERGENCY you can always bypass the magnetron
warm-up by holding in the ENTER key for 5 seconds.

For systems installed on recreational vessels, we usually see upwards of 12,000
hours of magnetron operation. That averages out to about 4 years of heavy use.
In many cases, however, we see magnetrons last 10 years or more.

Jim McGowan
Senior Product Support Engineer

Raymarine Inc.
http://www.raymarine.com




By the way, the spec for my SL70 dome says that the power usage is 28 Watts
transmitting, 9 Watts standby. That's a pretty significant difference.

-jeff


"Bruce in Alaska" wrote
"Jeff Morris" wrote:
I often keep it in standby to save power and
magnetron time (they do wear out)

Just a point of note here. Leaving the radar in standby on most
civilian consumer radars does not save anything on Magnitron
Time. What wears out is the Filiment (heater) and that is
always ON whenever the Powersupply is on, even in Standby Mode.
To convise yourself of this, do this simple test. When you first
"Fire up" your radar, there is a timer that allows the Magnitron
to "Heat up and Stabalize", usually for three (3) minutes or so.
After that initial "Warm up Period", when going from "Standby"
to "Operate" does your radar require another "Warm up Period"?
If so, then you are correct on your Magnitron time statement.(Not very
likely to be this way) If not, then then "Standby" only save you
Transmit Power, and that's not really very much in most cases.
Most modern Magnitrons have between 2000 and 4000 hours of Service
Life and that is Filiment Life, really.

Bruce in alaska
--
add a 2 before @