Would a sterndrive-powered bassboat be accepted in today's
market? Histor indicates that it might not. Sereral years ago,
Ranger offered both its 375 and 395 models with V-6 and v_8
sterndrives, respectively. They had a certain appeal, primarily
to those fishermen who simply didn't like outboards, and their
lever of performance was satisafactory but not spectacular. Too few
were sold to justify continued production. Ranger also developed a
MerCruiser sterndrive with a blackhawk drive that performed well,
but required so many hull modifications that it never made it into
Much has changed in recent years, however. The EPA is comming
down hard on outboards, and those that are acceptable are becoming
heavier and more expensive. Taking all of these factors into
consideration---- emissions restrictions, weight and cost----Mercury
concluded that sterndrive propulsion might be worth another look.
MERCURY AND STROKER TEAM UP
B&WB was fortunate enough to be invited to spend a day at one
of Mercury's test facilities, Lake X, buried deep in the swamps of
Central Florida. The subject of this test was a Stroker bass boat
powered by Mercury Racing Division's 360 hp Scorpion small-block
V-8 using an extensive array of props, special tools and testing devices.
Let's get to the nitty gritty. The boat had been clocked at 97.5 mph on
a cool day in Tennessee. The day we tested it at Lake X was hot and
humid. Even thought testing began at just past dawn. the best we could
manage that day at Lake X was 94.3 mph.
Those speeds were recorded by Lake X Operations Manger Robert
Moore, who is also a professional boat driver. To get the most out of this
package ----- or any high performance boat ---- requires the proper and
skillful application of throttle and trim to get the prop hooked up, plus
a tender touch at the wheel.
When driving , the most noticeable feature of the boat is its stability
and steering ease. Chine walk is minimal, and Mercury's power steering
makes control finger-tip light. The quick and light response caused me
to over-control and at WOT, a little bit of input at the wheel makes a
big difference in the direction the boat is going to go. I'm happy to say
that my driving skills improved that day with each run.
This was an wzperimental package that is unique in several ways. The
engine is a modified Chevy 350, bored and stroked to 377 cid. The
Scorpion was introduced two years ago as a high - performance
skiboat inboard. This year it was mated with a Bravo 1 sterndrive
with a choice of two lower units, one with a low - water pick - up to run
at elevated heights. This unit ---- not available at presstime, but ex-
pected soon --- has a special drive that is 2 inches shorter that stan-
dard length, which alows the prop to run in anelevated position with-
out the need to raise the engine in the boat.
The initial trials of the day were conducted with a 1.36:1 gear ratio.
Several props were tried, ranging from 28 to 30 inches in pitch. Prop
styles ranged from choppers with over-hub exhaust to the fairly con-
ventional big-blade offshore props with through-hub exhaust.
Moore indicated that a light boat in this speed range might perform
better with a little more gear reduction and a higher pitch prop.
Heavier performance boats do better with lower-pitched props.
The Stroker went back to the shop for a gear ratio change. With
1.50:1 gears installed, the test props ranged from 30 to 32 inches in
pitch. That gear ratio changed was good for approximately 500 rpm
and the test with the 30-inch pitch props sent the tachometer to the
redline and the engine to the rev limiter set at 5475 rpm. This engine
develops peak horsepower at 5400 rpm and the fastest time of the day
was set with an overhub-exhaust chopper
The easiest-handling prop is not always the fastest, and for those of
us with less experience in 90 mph boats, the prop fo choice was a 32-
inch-pitch offshore, a prop that provided nearly neutral steering and
more bow lift than the boat needed.
HOW MUCH SPEED CAN WE EXPECT?
When this sterndrive project started, the goal was to build an 80 mph
boat. the fact that we have seen the hight 90s raise our expectations
and the goal is now 100 mph. Both Robert Moore and "Chub" Bryant
of Stroker boats feel the goat is attainable.
The next step is to raise the prop height even more. Mercury has lower
units that are five inches shorter than normal, which the engineers and
field reps can use to determine the proper setting for the sterndrive.
(Once set, sterndrives are a lot harder to move than outboards.)
Several 1-inch spacers allow the drive to be extended to normal length
in order to determine the proper height to cut the transom. This is known
as the "X" dimension, and it is the lenght of a vertical line from the bottom
of the hull to the center of the propshaft. Just like an outboard, the less
lower unit we put in the water, the faster we go.
The Stroker boat was impressive. It is built for fishermen, big fishermen.
Bryant is a husky guy who found that narrow boats and heavy fishermen
don't make the best combination. The Stroker is wide with good flair at the
chine. The width, at rest , is carried well forward, which contributes to
stability, and that width also makes the hull a good candidate for heavier
sterndrive power. The bow is fairly low and won't catch a crosswind, an
experience that can be unnerving at high speeds and hard on the batteries
when fishing the points. There is not much boat in the water at top speed,
nor at any planing speed, yet the ride is soft, comfortable and controllable.
Though experimantal, the engine installation was neat tidy but, as the
photos show , not complete. Everything forward of the enging showed a high
degree of craftsmanship. Sturdy lids, lotslof storage, top-quality upholstery
materials and stitching add up to a boat any owner would be proud to show.
The Stroker was color-coordinated to match the deep-blue paint of the Scorpion
engine. With the open engine compartment, a sterndrive engine and over-transom
exhaust, this package attracts attention anywhere it goes. B&WB
"Chub" Bryant, owner of Stroker Boats, is interested in any comments
you may have about sterndrive options and the boat in general.
If you like what you see, drop him a line at
3944 Old Niles Ferry Road
Maryville, TN. 37801