Oh hell, let's have some fun .... comments interspersed.

JAXAshby wrote:
The Nattering Nabobs of Knighted Nowhere went all aground falling over
themselves making wild claims about accuracy of something they knew nothing
about. Silly negative gnomes, they confused equipment with technique, even as
they talk about threading their way through granite ledges along a fog bound
Maine coast.

As Jeff has said, YOU are the only one threading his way through granite
ledges, in fog. The rest of use were making approaches to land, in
waters that gave use some room for error when using the subject
equipment. (error on your part)

So, let's look at RDF, its accuracy and how it is used.

Consider that one is on a boat in a fog with granite ledges nearby just below
the water surface.

Don't know what that has to do with the subject at hand, but, continue.

One hears a fog horn or clanging bell somewhere off to the right. The chart
shows the source of the sound. You ask the helmsperson to hold the present
course as best he can. You face the sound as best you can, listen closely to
get the direction and point a magnetic handheld compass at it. Now the boat is
pitching up and down in the waves and rolling side to side. Each pitch up, the
compass turns one way, each pitch down the compass turns the other. Same with
each roll side to side, one way the compass turns one way, the other the other.

Here's a good indication of your lack of experience. No navigator, would
ever use the sound of a fog horn or bell to get a bearing, other than to
say, "It sounds like it's to stbd", "It sounds like it's to port", "it
sounds like it's ahead", etc..
There are, generally, two ways to get a bearing on a small boat. Either
a hand held compass (don't like them, but they have their place) or some
method to either read a magnetic compass bearing or relative bearing of
the object.
If using the boat's compass, you don't just ask the helmsman to try to
steer a steady course, you have him give you a "mark", when on course
(not perfect, but narrows the error).
Naturally, there is going to NORMALLY be some movement (rolling and
pitching) but here is where practice and teamwork come into play. (error
on your part)



Now depending on how well a steady course was held and how well you
listened/heard the sound and how well you interpreted the compass movement, you
have a siting *to* the sound. This you write down. It may or may not be
accurate to plus or minus 5 degrees or 10 degrees or even 20 degrees. but you
have the reading.

Hell, I'd say you would be lucky if you got within 30 deg +/-. (BS on
your part)


Then you do the same for a sound off to the left (hopefully 90 degrees from the
first as this gives less uncertainly of position in the end), getting a reading
to the other sound, also of the same accuracy.

Now, you mark off on the chart the recipical of the first reading from the
first sound, makng note of the potential variance of the reading, then mark off
the recipical of the second reading again noting the potential variance of that
reading, plus you make allowance for the fact the boat *may* have moved
(between the wind, the current and the engine the boat may have gone anywhere,
including backwards if the current overpowered the engine) between the first
and second readings.

This is all part of doing a "running fix" .... something you don't seem
to know or understand. Thankfully, most boaters have a higher degree of
"spatial awareness" than you.
At this stage, I'm totally amazed you think that any of this is above a
very basic knowledge of navigation. (will call this Error on your part)

You are left with an "Area of Probable Position" that might go up to 20 degrees
either side of the first siting on one side, up to 20 degrees either side of
the second reading, plus maybe a couple hundred yards forward or backward or
left or right.

You really do need to take a course on navigation. (error on your part)

THAT -- with minor differences -- is RDF, and one hell of a long ways from "2
degrees" accuracy as claimed by one of the silly negative gnomes of the
Nattering Nabobs of Knighted Nowhere.

No, THAT, is STUPID navigation, which coupled with the fact that you
consider them closely related in any way, other than the fact that they
involve bearings, tells us you have no understanding of that which you
speak. (error on your part)

Not exactly good for threading one's way through granite ledges, but if one is
far enough away from known granite ledges not all that bad as compared to just
bobbing around in the water.

ewwww, an admission of error about what you have said?

Now, before any of the silly gnomes starts screaming "THE DIFFERENCES ARE
IMPORTANT!!!!" let's look at the differences between Auditory Direction Finding
and using a Radio Compass.

"With baited breath" ......

First off, your ears can tell the difference between a sound in front of you
and a sound behind you. A radio compass can't.

It's why many RDF's incorporate a "sense" antenna, for those who are
truly lost.


Second, because you have two ears set apart your ears are excellent at
determining the direction of the sound by listening for its loudest. A radio
compass is poor at this, but better at NOT hearing the sound when the antenna
is at right angles to the source. Therefore, with a radio compass you have to
listen for the weakest sound, not the strongest. radio compasses will usually
have an analog meter installed to help the operator find the weakest sound from
the signal.

Actually, when listening to the "loudest" sound, the antenna tends to
approach that more slowly, so that it's rather difficult to pick out the
point of loudest sound, accurately. However, when swinging for the
null, the change is more rapid and easily discerned by the human ear,
which is why the "null" is used. The addition of the meter, was a nice
add on, but usually was used in conjunction. (error on your part)


In addition, the source points for sound are typically quite close, often only
a few hundred yards away. The source points for a radio compass are usually
some miles away and can in fact be thousands of miles away (miles is more
usual).

Buncha BS. Rarely, would anyone use a RDF signal at thousands of miles
..... too many corrections needed. (error on your part)

sound signals are easily heard. radio signals are usually weak enough so that
on even the best of radios the operator has to use headphones to hear them at
all.

More BS. Most of the radio signals, used for marine RDF, where fairly
strong. Since the vessels tended to use stations close to their
approach, signal strength was rarely an issue, unless you were trying
some long distance work. Many times, we used headphones mainly to void
other sounds around us, but generally, it wasn't necessary. (error on
your part)


a handheld magnetic compass can sense direction without regard to the direction
of the boat. a radio compass is first set in place, then the helsman is told
to hold a steady course on his magnetic compass (which he may or may not do
well, particulary if the boat is pitching and/or rolling, but in any event not
likely to be closer than plus or minus 5 degrees), the radio compass operator
then lines up the dial on the radio compass with the magnetic direction he
believes the boat is going.

More indication of little experience or first hand knowledge.
The RDF was normally mounted someplace below, and aligned with the
centerline of the boat. I had a second spot on my hatch cover, since it
allowed me to use the bearing circle to take visual bearings.
The helmsman is EXPECTED to hold a steady course, but when taking RDF or
visual bearings, he would give a "mark" when on course. You're above
description is amateur BS. BTW, boats aren't always rocking all over the
place, and not all helmsmen are "snake wakes". (error on your part)

The radio compass operator then tunes in a station frequency (he has a table of
station frequencies for the area) until he has a strong signal in his
headphones. He listens to the morse code identifier of the station that he is
looking for, gets it, then turns the top dial on the radio compass until the
signal is weakest (he may use the analog meter to help him indentify the point
at which the signal is weakest). This top dial is about the size of a dinner
plate and is marked off in degree (THIS is the reason the silly negative gnomes
of the Nattering Nabobs of Knighted Nowhere *claimed* accuracy of two degrees.
The dial can be read down to two degrees). the radio compass operator writes
down this reading.

Depends on the system. Some dials were marked in degrees, so, NO jax,
that is not the reason. Accuracy of the system was claimed to be, and I
quote from Bowditch "In general, good radio bearings should NOT BE IN
ERROR (my emphasis) by MORE (again) than 2 deg. for distances under 150
nautical miles". (error on your part)

The radio compass operator tunes in a station (hopefully about 90 degrees) to
the other side of the first station, asks the helmsman if he has stayed the
course (helmsman says Yes) and proceeds after some time to get a second
reading.

Wrong again .... have you ever done any navigating except on land?
(error on your part)


Radio compass operator now draws the lines on the chart from the two reported
radio stations, expanding the "Area of Probable Position" to allow for the
likelihood that the helmsman was not entirely accurate holding the course as
the radio compass was aligned with the boat's magnetic compass, nor was the
helmsman likely to be completely accurate in holding the course was the station
readings were made. The radio compass operator also takes into account that
the boat was moving between the first and second readings. Radio compass
operator also takes into account the whole thing was based on the helmsman's
read of *his* magnetic compass AND holding an accurate course long enough to
align the radio compass.

LOL You've never done this, have you? ( lack of knowledge on your part)


That's it, folks. THAT is RDF, using a "radio compass" as the equipment was
originally called.

-----

Now, who the hell would try to thread the granite ledges in a fog with that
kind of information?

I might try it, if I had some people on board who could steer, and a
good calibrated RDF, and some good stations to use (not likely
nowadays), and I had to get to port .... but, by then, I'd probably be
using some other form of navigation, if available, or would have headed
to sea till things cleared, or anchored.

Well, the Nattering Nabobs of Knighted Nowhere claim they did it all the time
and they survived so it has to be accurate "to within 2 degrees". Of course,
one of those silly negative gnomes also said he used a paper sextant in the fog
to tell him where he was going.

Yeah. Paper sextant and radio compass in the fog in the granite ledges.

G You DO have a serious reading comprehension problem, don't you.

otn

Now, let's sit back and wait for the silly negative gnomes of NN of KN jump all
over like Mexican beans on a hot skillet trying to say that "Ships didn't have
mobile radio compasses, so they weren't aligned each time they were used...",
and so forth. The idgits confused equipment with technique simply because they
didn't understand the technique. Lucky *******s they were if they really did
blunder through the granite ledges in a fog. Many other people weren't lucky.

Seems, that unlike you, we understood the technique AND equipment to a
far greater degree, since your dissertation was full of errors in
technique as well as equipment.

otn .... had a bunch of spare time whilst the Lobsta were cookin.....