[Rhodes22-list] Measured Hull Speed

[Christine Allison]

<I really do consistently get a reading around 6.25 just using my motor at
50% of throttle, when not planing, and not running with the tide.>

It may very well be possible to get that much speed from a larger size
motor.  My remarks referred to speed under sail and on a reach at that.  I
cannot do much more then 3.2 to 3.5 knots close hauled and beating into a 6
to 10 inch sea.  Believe me I have tried!

There is no way my 5.5 Nissan (even at full throttle) is going to deliver
more then 5.2 knots.

As you may know it's entirely possible to drive a displacement hull at
greater then it's computed hull speed.  A famous example comes to mind.  The
South Dakota class battleships could operate at greater then hull speed
because they had enormously powerful propulsion machinery.  Hull speed is
not a brick wall phenomena.  But the required power curve begins a very
steep ascent once you excede it.  It goes without saying there are a lot of
downsides to this procedure.  In fact the later Iowa class ships were lofted
with a much longer hull in order to obtain a service speed of greater then
30 knots.  This without resorting to the earlier brute force approach.

<Roger's is an older hull--is yours older?  Mine is a 1998.  Could there be
a difference?>

Mine is a remanufactured 1990.  Since the same molds were used I doubt if
there is any significant difference.

Richard Smith