Re:[Paddlewise] Crossings in Fog

        No fog crossings, but this experience seems germane: 

        I took my GPS out on the Willamette River around Ross Island. This
is the widest spot on the river, and there's some channels and river current
to play around in. Most of the time the current is about 2 knots, so this
gets you off course when you're crossing the river.

        Anyway, I marked a waypoint at the put-in near the Selwood Bridge.
Not only is the bridge visible from several miles, there's a bright "store"
at the end of the dock which is easy to get a fix on. So it's possible to
point the bow directly at the way-point and do a dead-reckoning. 

        The GPS has a screen that computes "cross track error" --the amount
of "slip" off course that you're doing. It also prints out precisely your
heading in degrees --not just a tick on the compass face, this is a digital
read-out. Then there's a bearing reading and an arrow that shows how to
correct your course to make your waypoint. The GPS even computes your speed
and "estimated time enroute" --which is nice in the dead of winter when you
want to get to the haul-out before dark. OK. . . the GPS also tells you the
time for sunrise and sunset at your location. (More data than I can use!) 

        Anyway. . . I'm using all this data in clear weather just to compare
my unassisted dead-reckoning with all the digital data. This is, of course,
on a river where the current varies owing to pilings and docks in the
channel, bends in the river, whether you're in the center or on the edge of
the channel. . . So the bottom line is that you can't keep on course no
matter what! 

        Additionally, just this week-end on Willapa Bay I was heading for
Pinnacle Rocks a couple miles away. I had a clear fix on the rocks, but was
working against the tide coupled with a gusty cross-wind. There are stakes
in the bay that mark oyster beds so even out in open water these provide
bearing points. I was amazed to find myself being blown sideways across the
water. The boat wasn't weathercocking because I was pretty much exactly
broadside to the wind, but I kept watching the stakes cross my bow at right
angles. 

        The upshot is, I suppose, that it seems nearly impossible to factor
all the variables in heading and course so that you don't miss your
objective over any significant distance. It may be possible to make a large
landfall, but trying to find a channel mouth or a dock in the fog is going
to be pretty "touchy-feely."

        Geo. 

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