In many places you use the numbers from last time. Many of the numbers are
published in guides or privately. You can also set up the course to
minimize exposure.

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. Go slow when in doubt.

Jim Donohue

"Dave" wrote in message
...
On Thu, 20 Jan 2005 21:47:14 -0800, "Jim Donohue"

said:

And it is
known the charts have a substantial inaccuracy. With GPS and radar it is
a
reasonably safe task.

OK, how is that GPS going to help you avoid hitting that rock that's shown
in the wrong place on the chart?