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.
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 razorsharp 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.
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.