This is a well know effect and you can even see it in something as
easy moving as a kayak. Find a tapered sandbar and a spot where there
is two to three inches of clearance over the bottom. Then paddle fast
over it. You will stick hard, stop, and then float off. The waves
that roll in and break will show you how much water even a kayak
moves. It's a very interesting demonstration of hydrodynamics.

--

Roger Long



"Garland Gray II" wrote in message
news:K%HGd.77623$Jk5.65403@lakeread01...
What I recall reading about the QE2 hitting the rock there (divers
confirmed
that there was recent bottom paint scuffed on the rock, and I don't
think
there was an indication that the rock had less water than the chart
showed)
is that she was running at too much speed for that little clearance
between
hull and sea floor. The hydrodynamic forces from speed in shallow
water will
pull the stern down. I see this happen frequently, and when it does,
besides
thinking about QE2, I know I'd better head to deeper water, or slow
down.
I just couldn't believe the captain didn't think about this when he
was
steaming along near the rock.

"Roger Long" wrote in message
...
Yeah, the QEII (I think) ran aground about 20 years ago just off
the
Elizabeth Islands on Cape Cod and in one of the most heavily
traveled
areas of New England. The chart turned out to be wrong.

--

Roger Long



"Glenn Ashmore" wrote in message
news:mgwGd.21097$EG1.17828@lakeread04...

http://www.goupstate.com/apps/pbcs.d...NYT02/50115036
0/1051/NEWS01

Not that any of us will be cruising at 30 knots 500 feet below
the
surface
but navigating soly by GPS you are just as blind. Many of the
charts we use
are from surveys over 100 years old.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress
(or
lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com