There’s a fair number of boat buyers today who truly believe that more is better when it comes to multiple outboards. With boatbuilders and dealers happy to oblige, this has led to some outrageous multiengine setups, including five and even six big outboards per boat. You find them hanging off the transoms of 35- to 45-foot go-fast center-consoles from builders like Contender, Deep Impact, Intrepid, Invincible, Midnight Express, Outerlimits and Yellowfin. These outboard setups get “oohs” and “ahhs” at boat shows and marinas, but it’s debatable whether the extra engines are for performance or just a means of conspicuous consumption.
A more common choice in multiengine configurations is between three and four outboards. Yet how do you decide between the two? First, make sure the boat is rated for the extra weight and power of a fourth outboard. If it’s not, your decision is made — trips win.
One goal of adding a fourth engine is greater velocity. Yet, does more power always result in more speed? Let’s try to answer this and other key questions when deciding between trips and quads.
Four outboards cost more than three outboards. Duh, really? But how much more? To give you an idea, Suzuki’s DF250AP V-6 outboard carries a manufacturer’s suggested retail price of $24,750 (25-inch shaft).
Of course, no one pays full manufacturer’s suggested retail price, but there are other purchase costs to think about with a fourth outboard, like extra rigging components such as steering, electrical harnesses, gauges and props that will cost thousands more, not to mention the labor.
Here again, it boils down to simple math. More outboards result in more maintenance — 33.3 percent more with quads versus trips. Labor aside, material costs are not exactly inconsequential. For instance, when changing the oil, if one big four-stroke outboard needs nine quarts of oil, that’s 36 quarts for quads versus 27 quarts for trips. At about $10 a quart for premium marine engine oil, that’s $360 for quads as opposed to $270 for triples. Apply the same multiplication factor to gear oil, filters, spark plugs and water pump rebuilds, and the extra maintenance costs for a fourth outboard add up fast. Then there’s the physical serviceability of quads.Sometimes, the four outboards are so close together that it’s difficult to even get the cowling off. Once you do, you can barely access filters and dipsticks because of the limited access between the engines.
Most people are aware that multiple outboards offer more control options than a single when maneuvering in close quarters. But are quads any better than trips at this? Not really. With trips, you can shut down the center outboard and use the port and starboard engines as you would twins. With quads, you have two propellers on each side of the boat, and that offers a bit more thrust for close-quarters maneuvers, so you might not need as much throttle. Yet the difference is negligible. Both trips and quads offer excellent control in tight marinas.
Some boaters believe that the more engines you run, the worse your fuel efficiency. But that’s not always the case. A lot hinges on how you run the boat. All other things being equal, if you run balls to the wall, quads will burn more fuel, and though you go faster, miles per gallon are usually worse than with trips at wide-open throttle. However, ease up a bit and optimum mpg can be quite close between trips and quads — though the speeds at which they achieve their best mpg will be different. Quads will be faster.
Unlike all-out speed, hole shot can improve significantly when you add a fourth outboard to the same boat. This is because you have more power and greater propeller blade area in the water for increased thrust. At the same time, drag is less of a factor as the boat is accelerating from a standing start. This can result in a two- or three-second decrease in 0-to-30 mph times. And while that might not sound like much, you can certainly feel it in the seat of your pants.
Going from three to four outboards on the same boat usually increases speed, but not proportionately to the increase in horsepower. Even though you boost the power by a third, the weight and drag of the fourth outboard prevents a corresponding increase in velocity. A six- or eight-cylinder outboard adds anywhere from 420 to 804 pounds to your boat. Its lower unit also generates additional drag. Drag increases as a coefficient of speed, meaning that the faster you go, the greater the drag. These factors negate much of the extra horsepower when it comes to boosting speed. Even so, the boat should go faster, with speed increasing anywhere from 5 to 10 mph over trips, depending on the power increase and setup.
OK, this isn’t exactly a performance category, but some boat buyers today place value on bling. They like to show off. And with this thinking, more is definitely better. So if you’re out to impress your friends, family, dock mates and passersby, four of a kind pays off.
When deciding between triple or quadruple outboards, remember that the biggest differences are in purchase price and maintenance costs, and in each case, trips are less expensive. In close-quarters handling and fuel efficiency, it’s a push. If you run them right, trips and quads are about equal in both categories. But if money is no object and you have the need for speed, acceleration and the ego boost that comes with showing off an impressive array of big engines, quadruple outboards definitely beat trips.