The Vulture debuted in
1977 and at one time became the best selling HydroStream model.
Think of a Viking with the added length placed in the center,
because that is exactly what HydroStream did - they cut a Viking in two
(right behind where the two windshield ends meet the sides of the deck) and added two feet to the middle.
This made it a very easy boat to produce. The first Vultures - maybe
the first 15 or so - had square corners underneath and an extended
pad. It worked well, but it didn't fit Pipkorn's concave concept, so
he filled it all in and made it concave. The result was that the
nose would not come up while running. The problem was similar to the
step experiment (see below): a vacuum was created in this back area - air
couldn't get in and water couldn't get out and it was like dragging a
pocket of water around until the hull could eventually break loose.
It took quite a few hours of testing to figure out the cause of the
problem and the resulting solution, some of which had Pipkorn leaning over
the transom analyzing the situation while underway. HydroStream's answer was to add two short strips of aluminum
underneath. These would push the water back down and prevent the
water from coming up around the edges to form a seal.
stepped hull boats are commonplace, but HydroStream actually experimented
with that technology soon after the Vulture came out. Pipkorn
experimented with steps in a Vulture but found it did not work well on a
20' V-pad speed boat. With their experiments, they found that the
steps actually created a vacuum and would pull the nose down. To
prove it, Pipkorn drilled holes in the bottom of the boat and installed
tubes in order to vent it. While underway, one could actually pinch the
tubes and make them whistle. Other problems with the steps were that
it did not help top end speed (the steps were out of the water anyhow), it
handled squirrelly in the corners, and it was tough to build. They
also couldn't go across the pad with the step because of problems with air
getting into the prop. All in all, HydroStream found it to be a
gimmick and one not practical for production.
Vulture tended to be a guinea pig for several experiments. Ron Baker
Sr. was involved with a stern drive Vulture
project while at Chrysler. It had a 360 cu. in. Chrysler with a
Chrysler drive. It ran 83 MPH but had no chance to beat the mod inboard
SK's and such. However, as Ron said, "we learned a lot."