K Smith wrote in message ...
Gary Warner wrote:
We bought the handheld Garmin 72 for our little 22 footer. We won't be
doing much if any long distance navigation, but just knowing our position
and just "playing" with the thing should be fun. Goofing around with it
inside (while it's cold and snowy outside) a few questions come to mind.

-- Lets say you are out in open ocean and heading for a waypoint that
it programmed into the unit. If everything was calm, no wind and no
current, all you have to do it point the arrow at the waypoint. But what
if there is a current and/or wind? Just pointing the boat toward the
waypoint might not take you on a straight course to the destination. You
would need to steer a different course to get the desired outcome. So:
Can this GPS (or others) help figure what course you need to steer?

-- I see there is a "Highway" screen that shows a "road" that one
might follow. Seems that may be the correct screen to do what I'm
thinking, but I can't quite figure out it's use.

Well, probably all this will become clearer when we can actually use
it ON the boat.

Oh, any good books out there telling how to use a GPS (not a manual
for a particual unit, but a general 'how-to' book of ideas and uses?

Thanks,
Gary




They're great but don't become complacent, even well experienced pros
end up on the bricks when they get too confident:-)

Even for a short trip use lots & lots of waypoints, the arrow points to
the next waypoint "all" the time, so if there's a cross tide/wind etc
etc you might finish well off your intended track, however still happily
headed "directly" to the next waypoint, via the car park:-).

As well as lots of waypoints, don't just place them at fixed intervals,
position them strategically; e.g. say there's a headland or reef to get
safely around, place at "least" 3 waypoints on your intended safety
margin track around/past it, one a reasonable distance before you get
anywhere close, then one off the reef or whatever & another as you exit
the area into clear water again. The risk is as above that you'll be
swept sideways & actually be approaching the danger from other than your
intended track & even though you'll be getting readings that confirm
you're such & such a distance from the "waypoint" your approach to it
may take you into the danger area. Again once at the waypoint your exit
from that risk area needs at "least" another for the same reasons.

Obviously lots of people can input the waypoints as they complete a
regularly traveled trip but if you are entering your intended waypoints
from a chart, then join them all up & mark the true & compass courses
between them on each little leg. After you've entered them, you can run
through the passage on the gps & it'll give you the bearings from each
waypoint to the next, take care these are the same as your plotted
courses, it's extremely easy to mis-enter a co-ordinate & this check
will show it immediately. It's also nice to have the tracks courses
marked on the chart, so you can confirm at a glance what the GPS
"should" be telling you, also note the soundings & just get used to
confirming them.

They're never, not ever wrong, if they're working with enough sats up
then they're correct:-) So no matter how disoriented, tired, wet, cold,
****ed off or in a hurry to get in, don't believe your gut or your
balance or or your assessment of distance over water or the advice of
the crew, if it's up & working it's right!!

K

If you use "lots and lots" of waypoints, you may run out, and that is
bad, especially in open water.