On Thu, 20 Jan 2005 20:01:02 -0500, Jeff Morris
wrote:

Sailors in 1975 were much better navigators than today.

========================================

That's probably a true statement as far as it goes. We had to be
"better" navigators in terms of skill breadth and techniques. It was
a matter of survival. To some that was all part of the challenge and
fun, to others it was just something that had to be done so that you
got where you were going. Reality is however, that many of those
skills are doomed to obsolesence except among those who keep them
alive as a hobby, just like knowing how to shoe your own horse or brew
your own beer. Is that a bad thing? Perhaps, but there is a good
side also. It is REALLY nice to know where you are at all times, and
if practiced prudently, is a lot safer also.

Sailing in the 70s was not always experienced navigators skillfully
finding their way no matter what. I still remember calls to the Coast
Guard from those lost in the fog asking for a RDF bearing to their
boat. The USCG actually offered that service in the early 70s believe
it or not, and could sometimes provide an approximate two bearing fix.
The one thing they would not do was provide directions for obvious
liability reasons. They would come out and try to find you however if
it looked like you were in danger as a result of being lost, and it
was not uncommon. Every person I know from that era, regardless of
skills, quickly jumped on the latest technology breakthrough as soon
as it became available at a reasonable price.

On Fri, 21 Jan 2005 08:15:10 -0800, "Jim Donohue"
wrote:

Go slow when in doubt.

==========================

Good advice.

Less damage to the rock, less damage to the boat.

On Fri, 21 Jan 2005 11:45:30 -0500, Jeff Morris
wrote:

Without the basic skills, you're in deep ****
when the GPS fails.

================================

No argument with the need for basic skills but there's no excuse for
GPS failure with hand held units selling for around $100. I was on a
Bermuda race in 1996 where we lost every electronic device on board
except my hand held GPS.

Wayne.B wrote:
On Fri, 21 Jan 2005 11:45:30 -0500, Jeff Morris
wrote:


Without the basic skills, you're in deep ****
when the GPS fails.


================================

No argument with the need for basic skills but there's no excuse for
GPS failure with hand held units selling for around $100. I was on a
Bermuda race in 1996 where we lost every electronic device on board
except my hand held GPS.


I've heard this often said, and in fact I keep an eTrex just inside the
companionway. However, things tend to go wrong at the least convenient
time. If the spiffy chartplotter goes south while your negotiating a
tight channel, its little consolation that a cheap handheld is
available. It may need batteries; it will probably take a few minutes
to power up; its only giving Lat/Lon which is of little value unless the
chart is handy; it won't have the current waypoint; etc., etc.

A hundred miles offshore, this is not a problem, but we've specifically
been talking about coastal cruising - the OP lives in Maine. The last
day I cruised Maine I was leaving Casco Bay in peasoup, and I had my
eTrex at hand with fresh batteries, just in case.

Wayne.B wrote:
On Thu, 20 Jan 2005 20:01:02 -0500, Jeff Morris
wrote:


Sailors in 1975 were much better navigators than today.


========================================

That's probably a true statement as far as it goes. We had to be
"better" navigators in terms of skill breadth and techniques. It was
a matter of survival. To some that was all part of the challenge and
fun, to others it was just something that had to be done so that you
got where you were going. Reality is however, that many of those
skills are doomed to obsolesence except among those who keep them
alive as a hobby, just like knowing how to shoe your own horse or brew
your own beer. Is that a bad thing? Perhaps, but there is a good
side also. It is REALLY nice to know where you are at all times, and
if practiced prudently, is a lot safer also.

Sailing in the 70s was not always experienced navigators skillfully
finding their way no matter what. I still remember calls to the Coast
Guard from those lost in the fog asking for a RDF bearing to their
boat. The USCG actually offered that service in the early 70s believe
it or not, and could sometimes provide an approximate two bearing fix.
The one thing they would not do was provide directions for obvious
liability reasons. They would come out and try to find you however if
it looked like you were in danger as a result of being lost, and it
was not uncommon. Every person I know from that era, regardless of
skills, quickly jumped on the latest technology breakthrough as soon
as it became available at a reasonable price.


You're bringing back memories with this. But who could afford a radio
in the early 70s? I thought I was well equipped with a spinner and a
Ray Jeff RDF. I think I finally got VHF (with 6 crystals) around 1980.

In article et,
otnmbrd wrote:

Jim Donohue wrote:



Why with professional luddites like you and your ilk I am required for
progress otn.

As stated, "you just don't get it". In truth, I'm a prolific user of
GPS, both the basic readout and connected to a chart plotter, making use
of all the information it supplies.
However, especially in the coastal waters I mainly traverse nowadays,
it's NEVER my sole source of position information and in fact, plotting
a GPS position isn't all that much quicker or necessarily as accurate as
a simple radar range and bearing, or eyeball fix.


The aside points out that the real amateur sailor with sufficient skill to
cross oceans uses GPS otn...and have a likely non working celestial
capability. It is in no way an excuse of any type...merely an observation
on how life actually is. You likely don't like it otn but you really don't
get a vote.

You use your survey as an EXCUSE for not learning or using celestial.
G By "non working" I assume you mean they have the ability but don't
use it. That's their choice, just like it's the choice of many ship
Masters making ocean crossings to require their people to occasionally
take celestial fixes and when in sight of land or radar range, to take
visual fixes as well as radar fixes and compare them to the GPS.
I also note that in another reply, you are still not comfortable using
radar for navigation.... that's too bad.... you're missing out on a
great tool.

otn


I would like to add a simple note here.

OTN talks about using Radar and the Mark One Eyeball to get position
fixes while navigating in coastal and inshore waters. Ok, that is common
practice, and has been for MANY years.

Now consider the accuracy of those fixes, as compared with the accuracy
of an Electronic Position Fixing Device.

Mark One Eyeball.... Taking a sight with binocs even over a compass card
will usually get a line within a degree or two, IF the guy is really
good at it or is using one of those old WWII TBT's... Ok, now figure
that your going to have to do that on at least two bearings, and better
yet, three or four. Ok, now you have to go plot those bearings on the
chart using the reverse bearing from the marker you sited on, and then
figuring in the time difference between the bearings, and the speed of
advance, of the vessel, and you don't get a REAL FIX, but an AREA of
FIX that IS "Orders of Magnitude" bigger than the REALTIME GPS Fix.

Radar..... Same thing here, except that your bearing will tend to be
better, depending on the Horozontal Beamwidth of the antenna, and the
distance, and area of the target which the bearing is to. Again, the
AREA of the FIX will be smaller for the radar because the time to get
the bearins, (two or more) will be shorter, but the plotting times and
the speed of advance will be the same. Again the Area of fix will
be "Orders of Magnitude" larger than the REALTIME GPS Fix.

GPS Fix..... even with out WAAS, this should be in the 30 foot centered
circle, and the speed of advance isn't even a problem due to the small
amount of advance in the one second cycle times of GPS Calulations.
The same can be said for LORAN-C with modern day Receivers, that have
builtin Lat/LONG Calculators, especially if the route has been run
before, and Know Anomalies in the TD's are already accounted for.

Now all the above really is mostly not a GIANT Issue at 7 - 12 Knots,
as there is always enough time to figure this all out. However, I defy
anyone to show me how anything but a Very GOOD GPS Based Navigation
System can be used on a Fast Ferry doing 35+ Knots inside Boston Harbour.
Speed KILLS, and the faster these guys go, the faster one of them is
going to run the rest of us over, because the navigator isn't watching
where he is going, because he is busy PLOTTING his position.

Explain to me why this isn't a problem......


Bruce in alaska
--
add a 2 before @

On Fri, 21 Jan 2005 13:50:35 -0500, Jeff Morris
wrote:

You're bringing back memories with this. But who could afford a radio
in the early 70s? I thought I was well equipped with a spinner and a
Ray Jeff RDF. I think I finally got VHF (with 6 crystals) around 1980.

========================================

I had the same setup in the 70s. Still have the RayJeff RDF out in
the garage but think I chucked the VHF w/crystals when I cleaned out
up north and moved to Florida. I had 2 receive crystals installed in
the RDF for 2182 and 2670. Boats would call USCG on 2182 for a
direction check and then get switched to 2670 while they homed in on
them. It was pretty humorous listening at times. The REALLY well
equipped boats in the 70s had a double sideband MF marine radio and an
aircraft type VOR unit for direction finding. It was a big pricing
breakthrough when Motorola came out with a frequency synthesized VHF
for around $300. That unit sold with one of my old sailboats.

On Fri, 21 Jan 2005 13:45:49 -0500, Jeff Morris
wrote:

The last
day I cruised Maine I was leaving Casco Bay in peasoup, and I had my
eTrex at hand with fresh batteries, just in case.

=========================================

Good idea but I'd also recommend loading some key waypoints into it in
advance. It only takes a few minutes and can save a lot of fumbling
around if you need it.

"Jeff Morris" wrote in message
...
Jim Donohue wrote:
In many places you use the numbers from last time. Many of the numbers
are published in guides or privately.

Local knowledge is handy.

You can also set up the course to
minimize exposure.

You mean, like plotting a course using piloting techniques?

I mean like plotting the GPS waypoints on the chart. For a difficult
segment of a voyage I would certainly plot the course even if the primary
navigation is a chart plotter. I would have the waypoints in a secondary
GPS.

In general the errors are area wide. You work out the correction from
known objects. You use radar and the bottom to assure yourself you did
it correctly.

You mean, like using piloting techniques?

You cerrtainly back up your GPS course by what you have available
particularly when the charts or waypoints are suspect.

Go slow when in doubt.

Why would you have any doubt? Don't you have absolute faith in your GPS?

I have far more faith in a GPS, particularly a redundant pair, than I do in
a LOP from a physical target. I have complete faith in nothing. The use of
a GPS still involves risk...little things like entering a waypoint wrong can
play havoc with the best of plans. I generally set up a system where
waypoints are transferred from the chart plotter to a hand held and the the
handheld waypoints are then plotted on a chart. I have twice found courses
that attempted to sail through or very near small islands.

I would also note that dredging barges can appear in the damndest
places...and the radar image can be difficult to understand particularly
against prominent background. Slow right down until we figure it out.

Jim Donohue

Bruce in Alaska wrote:
In article et,
otnmbrd wrote:


Jim Donohue wrote:



Why with professional luddites like you and your ilk I am required for
progress otn.

As stated, "you just don't get it". In truth, I'm a prolific user of
GPS, both the basic readout and connected to a chart plotter, making use
of all the information it supplies.
However, especially in the coastal waters I mainly traverse nowadays,
it's NEVER my sole source of position information and in fact, plotting
a GPS position isn't all that much quicker or necessarily as accurate as
a simple radar range and bearing, or eyeball fix.


The aside points out that the real amateur sailor with sufficient skill to
cross oceans uses GPS otn...and have a likely non working celestial
capability. It is in no way an excuse of any type...merely an observation
on how life actually is. You likely don't like it otn but you really don't
get a vote.

You use your survey as an EXCUSE for not learning or using celestial.
G By "non working" I assume you mean they have the ability but don't
use it. That's their choice, just like it's the choice of many ship
Masters making ocean crossings to require their people to occasionally
take celestial fixes and when in sight of land or radar range, to take
visual fixes as well as radar fixes and compare them to the GPS.
I also note that in another reply, you are still not comfortable using
radar for navigation.... that's too bad.... you're missing out on a
great tool.

otn



I would like to add a simple note here.

OTN talks about using Radar and the Mark One Eyeball to get position
fixes while navigating in coastal and inshore waters. Ok, that is common
practice, and has been for MANY years.

Now consider the accuracy of those fixes, as compared with the accuracy
of an Electronic Position Fixing Device.

Mark One Eyeball.... Taking a sight with binocs even over a compass card
will usually get a line within a degree or two, IF the guy is really
good at it or is using one of those old WWII TBT's... Ok, now figure
that your going to have to do that on at least two bearings, and better
yet, three or four. Ok, now you have to go plot those bearings on the
chart using the reverse bearing from the marker you sited on, and then
figuring in the time difference between the bearings, and the speed of
advance, of the vessel, and you don't get a REAL FIX, but an AREA of
FIX that IS "Orders of Magnitude" bigger than the REALTIME GPS Fix.


On the other hand, if you punched in in the wrong destination, or if the
antennae fell off the GPS, an Eyeball LOP, however inaccurate, may show
the problem.

Radar..... Same thing here, except that your bearing will tend to be
better, depending on the Horozontal Beamwidth of the antenna, and the
distance, and area of the target which the bearing is to. Again, the
AREA of the FIX will be smaller for the radar because the time to get
the bearins, (two or more) will be shorter, but the plotting times and
the speed of advance will be the same. Again the Area of fix will
be "Orders of Magnitude" larger than the REALTIME GPS Fix.


Again, if the GPS position is faulty in any way ...


GPS Fix..... even with out WAAS, this should be in the 30 foot centered
circle, and the speed of advance isn't even a problem due to the small
amount of advance in the one second cycle times of GPS Calulations.
The same can be said for LORAN-C with modern day Receivers, that have
builtin Lat/LONG Calculators, especially if the route has been run
before, and Know Anomalies in the TD's are already accounted for.

Now all the above really is mostly not a GIANT Issue at 7 - 12 Knots,
as there is always enough time to figure this all out. However, I defy
anyone to show me how anything but a Very GOOD GPS Based Navigation
System can be used on a Fast Ferry doing 35+ Knots inside Boston Harbour.

I don't think the high speed ferries are allowed to do 35 knots inside
the harbor. They are supposed to slow to 8 knots when the turn the
corner into the inner harbor. The odd thing is that the Salem ferry
doesn't use the main ship channel; it comes down the narrow side channel
(Lower Middle) to save a few minutes. When its coming up your butt at
20 knots you have to just hope they know what they're doing.



Speed KILLS, and the faster these guys go, the faster one of them is
going to run the rest of us over, because the navigator isn't watching
where he is going, because he is busy PLOTTING his position.

Explain to me why this isn't a problem......

I don't think anyone would claim the the High Speed Ferry should turn
off their GPS, but I do hope that they look out the window on occasion.




Bruce in alaska