The problem with all the above
planing hulls was rough water perform-
ance. Before 1960 severe pounding in
any significant sea was part of the
offshore racing scene. This restricted
speeds. In 1960 C. Raymond Hunt
designed the first popular, deep vee,
offshore racing hull and Richard
Bertram’s Moppie won the Miami to
Nassau race. This hull carried the deep
vee cross section from the bow to the
stern with longitudinal strakes for lift.
Previous planing hulls had a deep vee
bow with a flatter stern and no strakes.
The style caught on and many similar
deep vee hulls dominated offshore
racing. Since any waves are large for
model race boats, modern racing mono
hulls are all deep vees.
Up to this point we’ve been ignoring
the effect of air. Since water is 800 times
as dense as air, the drag of an object in
water will be 800 times as much as the
same object in air at the same speed.
Try putting your hand in the water at 20
mph compared to sticking it out the
(Continued on page 18)
PROPWASH
October 2016
17
Probably the ultimate stepped
unlimited hydroplanes were the Hacker
designed My Sweetie and Miss Pepsi.
They had a main step with a bump step
forward and a stern step. At speed the
hulls ran with the bump step nearly out
of the water. My Sweetie won the 1949
Gold Cup . Miss Pepsi won the
Presidents Cup in 1950, 1951, and 1952.
She also won the Detroit Memorial Race
and the Silver Cup.
planing boats got wider and shorter than
high speed displacement boats. The
classic planing boat was designed to run
on smooth water. These wooden planing
hulls were the kings of pleasure boats on
lakes in the mid 20th century.
Early planing designs had continuous
bottoms from bow to stern. It was
realized fairly early that steps in the
bottom would reduce the wetted surface
even more. The first attempts used a
single step.
Of course, if one step was good,
more would be better. Eventually
shingled bottoms were tried. Some of
the most notable stepped hulls were Gar
Woods’ Miss Americas.
A classic speedboat planing
A Hacker 1928 stepped hydroplane
Some modern designs also use a single
step. The Alpha Z
Scotty, a 1929 Gold Cup racer
Shingled bottom
Gar Wood’s Miss America IX
My Sweetie bottom
My Sweetie at speed
Miss Pepsi
Dry Martini, a classic 35 foot Cigarette
1973 deep vee offshore racer
