Wayne.B wrote:
On Fri, 10 Mar 2006 19:23:54 -0500, Jeff wrote:


What kind of boats do you guys have??? You sound like a powerboater
claiming you don't have to think about currents because you're doing
30 knots all the time.

Where I sail there are frequently currents of 2 knots or more, plenty
to cause "spiral" for a slower sailboat.


You're doing something wrong. Before you start, first solve the
current vector problem using an estimated speed for your boat and the
average current speed/direction from your tide tables. Use that as
your initial offset to the rhumb line course direction. Once enroute
check the bearing to your destination using the weapon of your choice
- bearing compass, RDF, whatever. Your bearing should stay constant
if your offset is correct, otherwise make a correction plus or minus
and continue to recheck. There is really no excuse for being
accidently swept down current, even in Vineyard Sound.


In other words, if you don't do this, you'll spiral in, just like I
said. Even with a GPS, you'll have to understand setting waypoints,
x-track, etc.

If you take the position that humans are completely competent and
never make mistakes, and that equipment never fails, then your
conclusion follows quite naturally.

Larry wrote:
....
There's 3 handheld GPSs, not counting what any guests bring, and two
mounted 12V GPSs on Lionheart. There's 4 chart plotters if you count the
Yeoman marking the paper chart from them. I can flip some little toggle
switches in the NMEA network and force GPS data to power the network if any
component, like the multiplexer, should fail. I'd say we have a fair
number of backup systems in case anything short of EMP from a nuclear
strike happens, in which case navigation won't be much of an issue....

Sure wish he'd get the AIS transponder, soon.....(c;


Sounds to me like you have a boatload of people who have forgotten how
to use a compass, if they ever knew.

Jeff wrote:
Courtney Thomas wrote:

Jeff wrote:

Gary wrote:

otnmbrd wrote:

That same bolt of lightening will take out your calculator so you
then have to work stars long hand. It'll also kill your digital
watch and radio so you won't have the correct time. It'll
probably short out your boat so you won't be able to work the
stars out until light the next morning. The lightening excuse to
learn astro is BS. Learn it because you want to or take a couple
extra handheld GPS. Practice dead reckoning. Know where you are
all the time.

Gaz






Let's see...... calculator gone, long hand star calc's....add a
minute or two to the solution.
digital watch killed..... in that case I'm probably dead too so
what do I care.... always have a mechanical clock that you know the
error...no big deal, was done for years.
lights out?....lite a candle or wait till daylight.... what the
hell, it's offshore navigation, what's the rush....




And how did you check the error on that deck watch? Radio? What was
the error and how much does it change daily? Can't just do the time
check anymore. Damn lightening.




With all due respect Gary, I think you need a refresher course on
celestial. I wear a "windup" watch, and have two windup ship's
clocks. All of them are accurate to a minute a month, and have a
pretty consistent error rate. I generally set them once a week, so
the error is well under a minute. So, would you care to tell us what
the expected error would be for both Latitude and Longitude?

To be honest, I don't really buy the lightning argument either. But
I'm not sure some find fault in celestial because it is not accurate
to 3 meters.



Jeff,

I'd be very interested in your opinion of where to get an inexpensive
but reliable "windup" clock/watch ?


Did I say inexpensive? My watch is an older Rolex, and the clocks are
both Chelsea. The most accurate of the three is a WWII deck clock I got
for about $250. My point is not that windup watches/clocks are perfect
backups for their more modern counterparts, but that in a pinch
electronics are not necessary for navigation. Latitude can be
determined without time, and longitude can be determined within 30 miles
even with a few minutes error. Not great for long passages, but good
enough to get you home.

BTW, my father-in-law spent 17 days in a lifeboat at the end of WWII. He
was able to navigate about 1000 miles using a Movado watch.




No, 'I'... said inexpensive.

I was hoping you, or some other reader, might have a good suggestion for
obtaining a suitable windup.

Cordially,
Courtney

"Bob" wrote in news:1142065241.058975.105470
@i40g2000cwc.googlegroups.com:

where would you find the tubes?


http://www.tubesandmore.com/

Stay away from Ruby tubes from China....They suck. Russian tubes are the
best!

Russia still builds tubes because tubes survive the EMP of an atomic blast.
The scary part is there are people in all government bureaucracies,
including mine, that worry about electronics surviving.

I sold 4 tubes just this week! Old Hammond organs are all tubes...(c;

Jeff wrote in :

Ah, now you're claiming that it was illegal to cruise the Maine coast
before GPS! You're cracking me up, Larry!



Unfortunately, there's not "stupidity charge" for going to sea without the
latest and best equipment. One guy docked at J-dock in an empty slip
rented by a friend. He didn't stay long, just long enough to go up to the
marina office and rent a slip for the night. He couldn't call them because
HE DIDN'T HAVE A VHF RADIO OR CELLPHONE! The gas dock was full.

It's amazing how many boats are equipped like this.....

Jeff wrote in :

Sounds to me like you have a boatload of people who have forgotten how
to use a compass, if they ever knew.



You mean that big round thingy we moved out of the way to install the radar
display that bobs around and spins crazy when the waves slap the hull?
What kind of reading can you get from something swinging 30 degrees off
course?

Just kidding. It's there and we use it, sort of. Over time, we made up a
compass correction chart for it using the chartplotter headings and compass
readings. The chart looks like a big sinewave. The compass reads
correctly at 2 points where the chart crosses zero. Otherwise, it's off by
as much as 13 degrees at two other points at the peaks. Totally disabling
DC currents has no effect. I have all the wiring as far from it as
practical. There's no close magnetic objects, either. All the electronics
is plastic with copper circuit boards. We tried to compensate it out with
the compensating adjustments and this chart is the result of the "best
setting" of those magnets.

Try that with your compass. Chart its error against the GPS headings over
time as you sail and plot it on a line chart. I was amazed how far off it
is. Sure glad we don't use it for NAVIGATION!....(C;

Larry wrote:
Jeff wrote in :


Ah, now you're claiming that it was illegal to cruise the Maine coast
before GPS! You're cracking me up, Larry!




Unfortunately, there's not "stupidity charge" for going to sea without the
latest and best equipment. One guy docked at J-dock in an empty slip
rented by a friend. He didn't stay long, just long enough to go up to the
marina office and rent a slip for the night. He couldn't call them because
HE DIDN'T HAVE A VHF RADIO OR CELLPHONE! The gas dock was full.

It's amazing how many boats are equipped like this.....

Unfortunately, not everyone get to crew on a rich person's boat with
all the latest gear, updated every year. Most of us make do with the
best we can. All the gear in the world doesn't compensate for lack of
knowledge and experience. I remember watching a 50 foot trawler run
aground on what looked like obvious shoaling to me. When I asked if
they need help he just mumbled "I don't understand ... we were going
right down the magenta line ..." This was on the ICW in GA.

30 years no one I knew had VHF, LORAN, or RADAR. Some of us had depth
sounders and RDF. But we all knew how to take a running fix, we all
knew how to read the water.

Jeff wrote in
:

Larry wrote:
Jeff wrote in
:


Ah, now you're claiming that it was illegal to cruise the Maine coast
before GPS! You're cracking me up, Larry!




Unfortunately, there's not "stupidity charge" for going to sea
without the latest and best equipment. One guy docked at J-dock in
an empty slip rented by a friend. He didn't stay long, just long
enough to go up to the marina office and rent a slip for the night.
He couldn't call them because HE DIDN'T HAVE A VHF RADIO OR
CELLPHONE! The gas dock was full.

It's amazing how many boats are equipped like this.....

Unfortunately, not everyone get to crew on a rich person's boat with
all the latest gear, updated every year. Most of us make do with the
best we can. All the gear in the world doesn't compensate for lack of
knowledge and experience. I remember watching a 50 foot trawler run
aground on what looked like obvious shoaling to me. When I asked if
they need help he just mumbled "I don't understand ... we were going
right down the magenta line ..." This was on the ICW in GA.

30 years no one I knew had VHF, LORAN, or RADAR. Some of us had depth
sounders and RDF. But we all knew how to take a running fix, we all
knew how to read the water.


LOL Can remember so many who swore they were in the middle of the
channel going down the ICW yet were hard aground.
How often such a simple act of watching their own wake and knowing what
it meant when it started overtaking them on one side or both sides would
have saved them a lot of embarassment and/or damage while following the
"magenta line".

otn

On 3 Mar 2006 14:57:52 -0800, "purple_stars"
wrote:

i know everyone uses gps. enough said.

but i also know that a lot of cruisers (most ? all ? all of the smart
ones ?!) use alternate methods of finding their position and navigating
to both keep their skills current in case of emergency, to double check
the gps equipment, etc, etc. some use celestial navigation, everyone
uses piloting skills, and on and on.

but do you still use RDF ?

if so, could you talk a little about what equipment you keep on board
for it ?

most of the RDF equipment i've seen looks really old!


As your question didn't pull any responses, I'll chew the rag, for
what it's worth.
There are at least four DF systems in use.
1) VHFDF
2) UHFDF
3) Switched antenna radio
4) movable directional antenna radio.

1) & 2) have only seen much use around planes. They are line of sight
aids. In the air, that's ok, hunkered down on the briney, not so
helpful.

3) Hams have built and used circular antenna arrays to provide a
rotating directional sweep.

4) Commercial radios with a top rotating ferrite antenna and a compass
rose. Panasonic made a portable 6 band of this kind - I have one in
the bathroom.

Not sure if radios in cat 4) are still available, but they would be a
natural low cost choice.

Brian Whatcott Altus OK
p.s. GPS made a lot of aids obsolete, right there.

In article ,
Larry wrote:

Jeff wrote in :

Sounds to me like you have a boatload of people who have forgotten how
to use a compass, if they ever knew.



You mean that big round thingy we moved out of the way to install the radar
display that bobs around and spins crazy when the waves slap the hull?
What kind of reading can you get from something swinging 30 degrees off
course?

Just kidding. It's there and we use it, sort of. Over time, we made up a
compass correction chart for it using the chartplotter headings and compass
readings. The chart looks like a big sinewave. The compass reads
correctly at 2 points where the chart crosses zero. Otherwise, it's off by
as much as 13 degrees at two other points at the peaks. Totally disabling
DC currents has no effect. I have all the wiring as far from it as
practical. There's no close magnetic objects, either. All the electronics
is plastic with copper circuit boards. We tried to compensate it out with
the compensating adjustments and this chart is the result of the "best
setting" of those magnets.

Try that with your compass. Chart its error against the GPS headings over
time as you sail and plot it on a line chart. I was amazed how far off it
is. Sure glad we don't use it for NAVIGATION!....(C;


sounds like someone needs or hire a GOOD Compass Adjuster to come
out and "Swing" that compass........