IMO, for the gps to compute a compass course to compensate for wind and
current it would have to have some means to acquire the inputs. In theory,
it could compute the cross track error and recommend a course to compensate.
Perhaps long stretches between waypoints in deep open water would be a
situation in which such calculations would be possible.

The type of boating in which most of us seem to participate with relatively
inexpensive gps it may not be quite so practical. Coastal cruising and
river and lake boating in my area is full of changing conditions due to the
shallow bottom conditions causing frequent changes in the speed and
direction of currents and the surrounding coastal structure which has a
similar effect on wind direction.

I'm pretty happy with the cross track error output on my gps. After a few
corrections on a long course I find it pretty easy to find a steady heading
that requires little additional human input.

Butch
"Gene Kearns" wrote in message
news
On 23 Dec 2005 22:07:18 -0800, wrote:


Question is:

What does one have to do to get to the target on a staright line? Lets
assume we dont make lots of intermediate waypoints.

My 276C has CDI (cross track thing or whatever) havent been able to
test it but wonder if thats the solution?

Yes, Matt, that is the solution... or part of it, anyway. First note
the compass direction that is required to arrive at the destination.
Next, proceed on course and watch for the amount of error that
accrues. Alter your heading a few degrees (as appropriate) and hold
that heading. You may have to make a few more adjustments along the
way.

Net result is that if your destination was at a GPS course of 000
degrees and you had a wind from 090... then without correction you
would end up tracking a path of (something like) 352 degrees... and
missing your destination, or having to sail "Direct TO" from the point
you figured out you were lost. If you pilot a course of 008, then you
should come out at your destination.

Bear in mind that your boat is "facing" a heading of 008, but is
actually traveling a straight line to 000.

--

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Grady-White Gulfstream, out of Southport, NC.

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