Paddler's Weight vs. Stability and Performance?
30 inches or more wide.
Richard
Brian Nystrom wrote:
Define "wide". In my previous posts, I was referring to boats in the
typical touring width range, which is ~20"-24".
Richard Ferguson wrote:
Sorry to be a little cranky on this thread. After messing around in
boats for 35 years or so, I know what boat behavior is normal and what
is not.
Let me ask a question of Brian and Marsh: If not overloading, what
could cause an ordinary (not narrow) recreational sit on top kayak to
become extremely unstable? I know that narrow boats are unstable,
which just makes common sense, but this was not a narrow boat. In
some private email, Marsh mentioned 17 inch wide boats; 17 inches
seems very extreme to me, and I would expect to swim often if I was in
such a boat. So tell me, how can one make a wide boat unstable, if
not by overloading or standing up?
I agree that in most circumstances, weight makes a boat more stable.
I am currently in the process of learning to pole my canoe, which
means I stand up in my canoe. I started out with a little extra
weight in my canoe, and swam once the first day. The second day, I
added more weight, securely tied town, and the boat felt a lot more
stable.
Richard
Richard Ferguson wrote:
Mike explained my situation better than I could. With the sot close
to sinking, which it appeared to be, the stability situation changes
a lot. I can easily imagine that this might not be typical, even for
an sot, which I suppose is why people are having trouble with my
experience and analysis.
This was not a narrow high performance type of sit on top, just
looking at it, you could see that it was an inexpensive recreational
type of kayak. I know a narrow boat when I see one, and this was
not a narrow boat. Brian and Marsh have basically ignored my
statement that this was not a narrow high performance boat that could
logically be expected to be inherently unstable for an inexperienced
user, but a wider recreational boat that should have been very
stable, but was very unstable for me. Mike at least is listening to me.
Richard
Michael Daly wrote:
On 19-Jun-2004, Brian Nystrom wrote:
(THS in MPH = 1.34 x the square root of the waterline
length).
Minor nit - that formula's for knots, not mph.
By the way , the guy did say he practically sank the sot. In that
case, stability would be limited and lifting his legs _might_ have
done the trick regardless of the CG change. His comment about the
elliptical section suggests that the sot has a bit of tumblehome.
That would mean that if he's significantly close to sinking, he
has no righting moment increase on heel. Any reduction in
stabilization ("sponson" effects, roll damping from his legs, CG
position etc) can undo everything.
While your argument is completely correct for the typical situation,
I think his explanation is a bit vague/difficult to envision - hence
he might be partially correct without being able to express it in
standard terms. The bigger problem is that he's viewing the general
characteristics of kayaks from his single, possibly atypical,
experience.
Mike
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