How Much Horsepower Do You Really Need?

When buying a new boat, or repowering an older one, consumers seem to have more outboard options than ever. It used to be that outboards were all about the horses, but today’s outboards might have digital controls, more powerful alternators, joystick controls and features that were not imaginable when motors were simply designed to turn the propeller.

“A decade ago, outboards were all about speed,” says Ry Landry, product education manager at Yamaha Motor Corporation, “but what you’re starting to see now is a big spread in the benefits an engine can deliver. It actually comes down to how and where you use the boat. Fishermen might go for maximum power because they want to get out to the fishing grounds faster, while a boater who intends to spend more time cruising may choose a less-powerful option because it may be more economical to operate.” But Landry points out that there are other factors to be taken into account. “There’s the load that may be carried,” he says, “and the conditions that the boater intends to operate in.”

Landry’s colleague, Brad Leatherman, the tournament support department manager for Yamaha Marine Group, says that he is not as interested as he used to be in pushing a boat at faster speeds, but he’d still prefer to have extra power in reserve to outrun a storm or punch through rougher seas. “I’d rather have it and not need it, than need it and not have it,” he says.

Leatherman says owners shopping outboards also have to weigh speed against economy because most outboards run at best efficiency around 4000 rpm. “A pair of Yamaha F200’s might push a boat efficiently at 33 knots, but a pair of F250s may push it at 43 knots at the same economy,” he says. “If lengthy runs are desired, I’d probably opt for the additional power to get me there sooner at the most economical speed.”

When it comes to picking an outboard package, purchase price, maintenance costs, engine weight, top speed, fuel burn, fuel type, fuel availability, handling, electrical demands, service availability and safety all need to be taken into account. One system may offer electric steering and eliminate the need for hydraulic pumps while another set of engines may allow you to stay on plane at a lower speed or give you a faster shot out of the hole.

Although outboard engines continue to get bigger and more powerful—Mercury Marine’s 7.6-liter, 600-hp V12 outboard is just the latest example—it’s no longer just about the ponies, which is why some boat builders offer multiple engine options for individual boat models.

To illustrate the options available in outboard power today, and how to select a package that’s right for your specific needs, we talked with builders of three boats in the 30- to 40-foot range.

SeaVee 322z

SeaVee Boats offers Mercury, Suzuki and Yamaha power packages on its line of high-performance fishing boats. “We will rig what the customer wants,” says SeaVee Sales and Marketing Director John Caballero.

On its 322z, a center console with a twin-stepped hull, SeaVee provides eight power options using twin 300s, 350s, 400s or 450s. The 322z is an offshore fishing machine, but the Luxury Edition is an upgrade that adds molded-in forward seating or a variety of removable rear benches. With twin 300-hp outboards SeaVee says the 322z tops out between 43 and 48 knots. With twin 400- or 450-hp motors top speed is 56 knots.

Caballero says the Yamaha and Mercury 300s are gentler on fuel consumption. “It’s a lighter weight motor, a simpler motor. It’s not supercharged,” he explains. “The 300 is popular because it gives you good overall performance. If you’re concerned about fuel economy, it’s for you.”

On the other end of the spectrum, says Caballero, the apex boater who wants performance regardless of cost will choose the two Mercury 450R racing engines. “The 450 is a relatively small, lightweight package. Horsepower to weight, there’s nothing that can top it. The performance is outstanding.”

Caballero says torque is often overlooked by those shopping for outboards. He points to Mercury’s 300-hp engines, which are built on a V8 block. “That’s a whole other ballgame with a couple more cylinders,” Caballero says. “You lose some speed at the top-end maybe, but some customers couldn’t care less about that. They’re more influenced by the hole-shot and the sensation of acceleration. You give the throttles a little nudge and you immediately feel like you’re going from 30 to 40. That’s more to do with the torque than the brute horsepower.”

Steering is another important consideration when evaluating outboards. Caballero says steering on larger motors has traditionally been hydraulic. “Once it’s purged and operating on a boat it’s reliable,” he says, “but a nick in the hose or a kink could affect the steering.”

He adds that a lot has changed since Mercury went from a basic hydraulic system to power-assisted, and that fly-by-wire has changed everything. He remembers there was a lot of skepticism about the longevity of these systems at first. “Cable-based systems were not a problem, but as they aged, you’d have to put more effort into moving those throttles,” he says. “If you kinked one of those cables, you were in real trouble. Now it’s [digital] data. When you send data to the motors, you have an instantaneous result, even if it’s the slightest change.”

Yamaha now also offers these features with digital controls. “Electric engine controls allow you to add things later, such as joystick control, dynamic control, autopilot modules and more,” says Caballero.

Caballero says power requirements on today’s boats are different too. With every new platform, he sees engine builders supplying more power from the alternator. “They see you have more [electronic] stuff on boats,” he says. “FLIRs, radar, multiple VHF radios. We have customers who have robust electronics packages with redundant electronics, or a stereo with 24 speakers and multiple amplifiers, so these 100-amp alternators weigh in on the overall consideration.”

Jeanneau Leader 10.5 Series 2

Jeanneau recently redesigned its 5-year-old Leader 10.5 model, and one of the things it beefed up was the transom. Now called the Leader 10.5 Series 2, the new twin-cabin walkaround also has a beefed-up, vacuum-bagged, resin-infused hull with a Michael Peters running surface. “It’s a whole different animal,” says Jeanneau America Sales Manager Wade Clevenger about the new family cruiser.

Jeanneau partners with Yamaha for its outboards, although dealers can outfit with Mercurys, too. While the original Leader 10.5 was offered with twin 300- or 350-hp Yamahas, the Series 2 can now handle Yamaha’s 425-hp XTO outboards. “You’re missing some hole-shot capabilities when you order the 300s,” Clevenger says. “You’re missing what the 425s can provide, but if you’re a price-conscious consumer, the boat still goes 41 knots with the 300s.

Clevenger says one of the biggest things that Yamaha came up with on the 425 is the electric steering that eliminates the hydraulic pumps. “It cleans up the transom and makes it pretty back there,” he says.

Yamaha’s Leatherman says there are three steering options to choose from with the 300s: a base-level system with conventional hydraulic steering; a fully electric system that bolts onto the engine in the same manner as a hydraulic system would; and a fully integrated electronic system that is built into the engine bracket on the 4.2-liter Offshore model. By using an electrical steering system, rigging becomes simplified. This eliminates the space-eating hoses and pumps, the need to keep the steering fluid under constant pressure and the potential for fluid leaks. Electric steering also draws less power compared with a hydraulic system.

The base price for a Leader 10.5 Series 2 with hydraulically controlled twin 300s is $210,000. With the 425-hp engines, the base price goes to $240,000. “It’s a jump for sure,” Clevenger says about the $30,000 price difference. “For the guy who’s looking for maximum speed, we have the 425. For the price-conscious consumer who is not interested in going 50 knots, we have the 300s.”

Fountain 34CC

Fountain Powerboats offers eight different Mercury power packages on its 34CC model with twin or triple 300s, 400Ms, 400Rs or 450Rs.

“Why do we have so many offerings? Because we can,” says Jeff Harris, COO of Iconic Marine Group, the parent corporation of Fountain Powerboats. Harris is also the throttle man on the Super Boat Wake Effects. Having sped across the water at more than 150 knots, he knows a thing or two about propulsion.

Harris says the 34CC, a twin-stepped center console, sits right in the middle between the popular twin-engine size and a beefier triple-engine size. “With triples, you break a propeller, that boat still pops up on two engines,” Harris says, adding that triples are beneficial if you’re offshore fishing or in a tournament.

You might think Harris would go straight for the triple 450R package, but he touts the benefits of the 34CC’s twin 300-hp package. “The boat has a 9-foot 6-inch beam, so it can handle three engines, but it’s a very efficient hull for twin 300s,” he says. “And the beauty of the 300 is 87 octane gas, which you can buy anywhere. You got a guy who runs around, and he only has to buy the cheapest gas.”

The twin 300s also provide the best range. At a 35-knot cruise, the twin 300-hp 34CC can go 650 miles on a tank of fuel. At the same speed, the range for the twin 450Rs goes down to 557 miles, and with triple 450Rs it goes down to 410 miles. Open the 450Rs up all the way and you can go 76 knots, but you’ll also burn 132 gph and bring the range down to 254 miles.

By offering multiple options on the 34CC, Harris says there’s something for everyone. “Mercury Racing puts some cool things on their engines that you can’t get on the 400M,” Harris says. “Even the new 300R has the new mid-section and integrated steering.”

The 450Rs will provide top speed and best low-end performance. Of course, that comes at a price, but as Harris points out, the people who buy the 450R want to go 60 to 70 knots and maybe look cool with three big motors. “It’s a status thing,” he says.

While the 450R has the bottom end and the top end, it’s hard to beat the low-end torque of the 300s. “The 450 is basically a similar engine with supercharging,” he says. “Nothing is gonna go like that.”

So, which power package is right for you? If going really fast is all you care about, the choice is pretty simple. But if speed isn’t everything, or budget is a consideration, be sure to weigh all your options. 

This article was originally published in the July 2021 issue.