We regularly run with the autopilot in NAV mode.  However, we ONLY run that
way with a competent watchstander on watch.  It then matter little which mode
you run in.  Its the watchstander part that is important.  I like to use the
NAV mode to adjust for current set, etc.  But I also like to do my navigation
the old fashioned way just to "keep my hand in the game".

Momma always said "Love many, Trust few".  I love my autopilot.

Regards,
Randy Pickelmann
MORNING STAR
lying in New Teakettle Creek, near Sapelo Island, GA
www.morningstar.talkspot.com

I agree with Randy. While the AP is steering to the next w3aypoint, I can
see if that waypoint is showing on the radar. I can double check the
chartkit and chartplotter to check again that there are no obstacles or
shallow spots ahead. I can look out the windows and check the radar for
other vessels. What I don't have to do is keep my hand on the steering wheel
all the time.

Ron Rogers
1985 Willard 40FBS
AIRBORNE
Lying Washington, NC
----- Original Message -----
From: "Randy Pickelmann" rwp_48@yahoo.com

| We regularly run with the autopilot in NAV mode.  However, we ONLY run
that
| way with a competent watchstander on watch.  It then matter little which
mode
| you run in.  Its the watchstander part that is important.  I like to use
the
| NAV mode to adjust for current set, etc.  But I also like to do my
navigation
| the old fashioned way just to "keep my hand in the game".
|
| Momma always said "Love many, Trust few".  I love my autopilot.

NAV mode is good. I used it all the time in those wide open spaces.  But it
does depend on nonfailure of GPS, or LORAN.

One time we were traveling down the Chesapeake Bay, headed to Solomons
Island, in NAV mode. Shortly after NAV turned us into the Pautuxent River,
near the Pautuxent Naval Air Station and still on track, Derreen made a hard
turn to starboard. A postanalysis after manually finishing the trip, showed
that the GPS had relocated us 30 miles to the south, somewhere near St Marys
on the St Marys River.

Since Derreen's GPS receiver continued to work properly thereafter, I
assumed the problem was with the satellites, or perhaps the Air Station was
having some fun.

Others report the same kind of problem going under the bridge on the Severn
near the Annapolis Naval Academy. I don't know. That' not a place where I'd
be in NAV mode.

-- Jim Ague

<<Is it normal to run without a route planned?  Are there that many
people out
there just winging it?

Even on the ICW, I like to make sure there is a "magenta line" or other
such
capability showing to make it obvious when turns come up.  Is this so
unusual?>>

Yes it is very normal.  I use my boat alot and the vast majority is just day trips.  I may do 2 or 3 in a week in waters I am extrememly familiar with.  So plotting a route would be a waste of time. I do, however use the GOTO feature more to get a distance and an ETE.  And your behavior has an extreme as well(this is not pointed at you...just a generalization).  One gets so wrapped up in the gadgetry and the magenta line that one ends up with his face burried in the screen....instead of looking ahead.  A chartplotter or any kind of nav equipment can be a huge distraction when you should be paying attention to were the vessel is heading.  A chartplotter or GPS is just a resource used to put the pieces of the nav puzzle together.

On another note, the military does jam the GPS signal fairly regularly.  I fly near the White Sands Missile range on a regualr basis and it is not uncommon for the air traffic controller to advise of GPS jammin in the area.  I would imagine they probably do this around Pax River as well.

Trawler on,
John

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Jim,
Although the military will not discuss it, it is clear to me that some sort
of jamming, whether intentional or not, goes on near many military bases.
I've had spurious GPS results near Kings Bay, GA and Annapolis, MD.  Other
cruisers have reported similar problems near other military bases.

Since I use my autopilot on Auto, this kproblem doesn't affect my boat's
heading.  I love my GPS even though I never trust it.

Mark Richter, trawler-yacht Winnie the Pooh
Ortona, FL on the Okeechobee Waterway

Mark,

It has been discussed in some very hard to obtain public documents
where the military has reserved the right to "degrade" the GPS signal
in and around their facilities to minimize the probability of a
successful attack.

I have heard, but cannot confirm that at nuclear weapons facilities,
somehow a random signal put the site somewhere in Brazil, Africa, and
other places... [Just rumor but seems that is the right thing to do...]

And, if you ever get to meet a person who works at the CIA
headquarters, ask them if their GPS tracker in their car works.....

Lee

On Nov 28, 2007, at 15:56 , Mark Richter wrote:

Jim,
Although the military will not discuss it, it is clear to me that
some sort
of jamming, whether intentional or not, goes on near many military
bases......

[demime 1.01d removed an attachment of type application/pkcs7-signature which had a name of smime.p7s]

It is not top secret.  Air Traffic Control will broadcast in the open when GPS jamming is in progress.

Trawler on,
John

Please visit www.trawlerforum.com

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