"Wayne.B" wrote in message
...
On 10 Apr 2004 13:45:52 GMT, (JAXAshby) wrote:
It is, of course, though many ignorant people will claim they read it in
a
book, so it HAS to be true.

====================================

There are hull forms that are not bound by their own wave train, or
are bound to a lesser extent (such as long skinny hulls).

There are two primary sources of drag on a boat: Friction ( a function
of surface area and smoothness), and induced drag imparted from
converting motion into wave trains. At low speeds friction dominates
as the primary drag factor, and as speed increases wave making becomes
the dominant factor in a non-planing hull. For an average
displacement hull the tradional equation works fairly well at
identifying the approximate crossover point, where considerable extra
power is required to go any faster.


Thanks Wayne.

Mark Browne

On Sun, 11 Apr 2004 16:43:58 GMT, "Mark Browne"
wrote:

Thanks Wayne.
========================

You're quite welcome. Hopefully I didn't belabor the obvious.

You're quite welcome. Hopefully I didn't belabor the obvious.


no, you didn't belabor the obvious. you did belabored erroneous, voo-doo
science as written by writers plagarizing other writers who plagarized others
who took to heart a silly, yet scientific sounding, explanation given to 19th
century British naval brass who couldn't understand why doubling the power to a
boat of the time didn't double the speed of the boat. the brit brass dumbly
nodded their heads and proclaimed to the Queen that they had the fastest boats
on the planet.

Is it your position that drag on the hull does not increase with
speed?

the induced drag on a hull goes up at the cube of speed and has nothing to do
with "climbing the bow wave". A cubic function is mathematically well behaved,
meaning nothing untoward happens anywhere on the curve.

for what, mark? for what?

Thanks Wayne.

Mark Browne

There are hull forms that are not bound by their own wave train, or
are bound to a lesser extent (such as long skinny hulls).

no hull is "bound by its own wave train". none.

induced drag imparted from
converting motion into wave trains.

bull. that is not what induced drag is at all. check your terms.

as speed increases wave making becomes
the dominant factor in a non-planing hull.

bull, induced drag goes up at the cube of boat speed and has nothing to do with
waves at all.

For an average
displacement hull the tradional equation works fairly well at
identifying the approximate crossover point, where considerable extra
power is required to go any faster.

bull. most every recreational sailboat made in the last 40 years regularly and
rather easily exceeds the speed predicted by "the tradional equation".