Re: [Paddlewise] Crossings in Fog

Geo. Bergeron wrote:
> 
>         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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The best answer is still the old pilotage trick of making sure you miss
your landfall either to the right or left. Then you are sure which way
to turn to find your destination.

Roger
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