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Triple and Quad Outboard Motor Installation
Boats Go Faster Rigged With Triple and Quad Outboard Motors
Back in the 60's, when Mercury Marine introduced the first 100 horsepower
outboard motor, the event left some dockside experts trembling in their
deck shoes. Naysayers warned that all that surplus horsepower was
dangerous and that death and destruction were most certain to follow.
History proved them wrong, of course. Armageddon did not crash down around
our ears. Instead, with the introduction of the then-thunderingly powerful
100-horse, boat builders went quietly about their work, improving hull
designs to take full advantage of the bigger motor.
It's just like today as cutting edge boat builders modify hull designs to
take better advantage of the new four-strokes. Also salient, back in the
60's, engine companies went to war to determine who could build the most
powerful outboard motor. Long story short, the evolution of boats and
motors continues to this day for the simple reason that the horsepower
wars have never ended.
Besides large displacement V-6 two-strokes, today's state of the art in
marine engines includes ultra efficient four-stroke and direct injection
outboards. These new wave, environmentally friendly, outboards boast razor
sharp acceleration. Their miserly fuel consumption bestows boats with
significantly longer range and at higher top speeds. Regardless, a
synergistic melding of engine and hull technology has spawned a
proliferation of triple and quadruple outboard motor installations up to a
mind-numbing 1200 horsepower.
Today Proline, Dakota, Midnight Express, Contender, Deep Impact, and
Angler all build 30 to 40 foot boats specifically engineered for triple
installations. Some of them also offer quadruple outboard powered boats.
Obviously the chief attraction of multiple engine installations is extreme
high performance. Triple and quadruple powered 30 - to 40- footers blister
the water at speeds of 60 to 70 mph. Cruising speeds typically register in
the 40 mph range. Clearly these boats are not intended for the feint of
heart. One builder joyously boasts that when the Gulfstream lays flat like
glass, his boats can make a Miami to Bimini run in 41 minutes flat. When
seas are rough, it takes only a little while longer.
Besides a pleasurably wild ride there's another compelling reason for high
horsepower installations. In a word, it is all about safety. Multiple
outboard motors equal redundancy. In the unlikely event that an engine
should ever give up the ghost miles offshore, the remaining two or three
outboards are sufficient to bring the boat home. And not just to limp into
homeport, but to bring the boat home on plane and in time for supper.
.
You've probably already noticed how most of the triple and quadruple
outboard boats are center console and open designs favored by tournament
fisherman. For a fisherman, ample power and high speed mean getting to the
bluewater sooner, the ability to stay there longer, and then get home in
record time. Some experts claim the trend towards triples should be
credited to the Southern Kingfish Association. As the story was told to
me, its members wanted the safety of redundancy and they also wanted to be
able to fish the Bahamas and get back home in the same day. So they
started asking boat builders for hulls capable of accommodating three
engines on the transom. As the story goes, once Proline started supplying
them, the others quickly fell in line.
You should also know that the triple outboard motor trend is in
transition. It's morphing over to other applications as savvy builders
have begun to add more and more accessories to their boats in order to
appeal to the more mainstream pleasure boating crowd. Here once again, the
attraction is speed and safety with a boatload of creature comforts thrown
into the mix.
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With all this in mind you might be wondering about the specific details of
multiple engine installations. For instance, exactly how does adding an
outboard motor influence top speed? The rule of thumb is that the top end
will climb anywhere from six to 10 mph. So adding a 225 hp to a twin
outboard motor installation that already goes 40 mph will raise top speed
to anywhere from 46 to 50 mph. Also, you can literally feel the difference
in acceleration in the seat of your pants.
Obviously fuel consumption also increases. Ultimately the exact amount of
increase depends on the hull design and whether or not the engines are
two-stoke, four-stroke or direct injection model. Generally though, figure
half the gallons per hour consumed by just twin outboards and add that
number to the twin’s gph. In other words, with twin 250 horsepower engines
burning 34 gallons at 4000 rpm. The same boat rigged with triple engines
burns 17 gph more for a total of 51 gph.

Researching this story over the course of a couple of months, I drove
about a dozen boats rigged with an assortment of twins, triple or
quadruple outboard motors. All of the boats were nimble handlers, and due
to waterline length and wide beam,, they negotiate rough water with ease.
Because this class of boats are relatively large, all over 30 feet,
they’re also equipped with a goodly number of amenities.
The helm station is large enough to accommodate large screen radar and chartplotter and fishfinder. The head is large enough to be comfortable.
Storage for tackle, gear and cold beverages abounds. Generator sets are
also common. Some include air conditioners that steam air toward the helm
station. And once again, because of the generous proportions of these
hulls, some of the larger boats even feature cuddy cabins replete with
V-berth and microwave-equipped galley. It’s like Luther Burbank
successfully crossed a Ferrari with an RV.
The real eyebrow raiser was the way a power package would so strongly
influence a boat’s personality. For example, I drove two Midnight Express
39 footers. The hulls were identical, having been derived from Don
Aronow’s 36 foot Cigarette. One boat was rigged with four Mercury Racing
XP300 engines and the other with four Honda 225 horsepower four-strokes.
The difference between them became apparent dockside, even before we had
even slipped the mooring lines. The Mercury Racing motor, a high
performance two-stroke, rumbled ominously at idle, its basso profundo
voice punctuated by a cloud of oil smoke. In sharp contrast, the Honda
four-strokes purred quietly. Under hard throttle both boats accelerated
like there was no tomorrow. Obviously the hull with 1200 horsepower ran
much faster than the one with merely 900 horsepower. It’s the difference
between an F-18 Hornet fighter plane and a Gates Learjet.
Another difference I noticed was the variations in control systems, both
steering as well as throttle and shift. The most common setup is the
venerable Gaffrig levers, with separate controls for each engine’s
throttle and shift. I also ran across the new wave Morse Teleflex system.
It rather handily combines throttle and shift controls onto a single
binnacle. With it there are fewer levers and more than one engine can be
controlled with a single lever.
No big surprise, steering is actuated by a powerful, rock steady hydraulic
ram. High performance Latham and Marine Machine systems are mandatory on
installations rigged with more than 750 horsepower. I found it curious to
see how on some triple rigged boats the engine cowlings are level with one
another. Such a configuration requires the port and starboard outboard
motor transom height to be 25”, with the center motor a 30-incher.
Conversely, some builders install motors all with the same transom height.
You can spot this by the lower the center cowling. Neither way is better
or best, just different.
Finally, boats suitable for triple and quad outboard motor installations
feature either a bolt-on or an integrated transom bracket. That’s because
transom brackets are renowned for the way they dramatically improve
acceleration, top speed, fuel economy and handling. They also allow tilting
the outboard completely out of the water.
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