Outboard vs. Sterndrive – Understanding The Right Power Choice for You
By: Craig Ritchie
There have been a lot of amazing developments in boating over the last few years, and one of the most exciting is the number of boat builders who now offer some of their top models with a choice of outboard or sterndrive power.
This new trend – which can be seen on boats by companies like Bayliner, Campion, Chris-Craft, Formula, Monterey, Sea Ray, Starcraft, Regal and Tahoe, among others – gives experienced customers the ability to choose the type of power that they prefer. The challenge is that less experienced boaters are often leftconfused, and wondering what the relative advantages of each style might be.
So which is better? In some cases the decision will be dictated by the style of boat. Surf boats universally use inboard or sterndrive power, for instance, while pontoon boats generally work best with outboards. But for many other types of boat the choice isn’t always clear. Let’s take a look at the advantages of each system.
Advantages of Outboards
1. Lighter Weight
As a general rule outboard engines are lighter than sterndrives of comparable horsepower. Where a 200 horsepower V6 sterndrive typically weighs in at close to 350 kilograms, a 200 horsepower outboard weighs anywhere from 220 to 24 kilos. That’s a pretty hefty weight savings by any measure.
The lighter weight of the outboard gives a boat a higher power-to-weight ratio, which can mean better top-end speed, hole shot and mid-range acceleration.
2. More Cockpit Space
It seems obvious, but perhaps the biggest advantage to an outboard engine is the simple fact it’s position outboard of the transom. Moving the powerplant to the outside of the boat’s cockpit allows more interior space – and especially in the case of smaller boats, where every cubic centimetre counts.
Sterndrive boats generally incorporate some sort of engine housing that extends above deck level. This is usually hidden under a big sun pad or transom bench seat to at least make the space usable, but it’s still a chunk of real estate that’s lost to accommodating the engine. Outboards, on the other hand, being located outside of the boat, eat up no interior space whatsoever. Some boat builders convert the space where the sterndrive engine would have went into a large storage locker for bulky gear. After all, if there’s one thing you can never have too much of it’s storage space.
3. Greater Tilt Range
The ability to tilt the engine completely out of the water when the boat is at rest gives outboards another big advantage over sterndrives. Tilting the lower unit clear of the water protects it from corrosion in saltwater environments, or from being fouled by marine growths like algae and zebra mussels in freshwater systems.
It also allows boaters in northern regions to extend their season. Because all of the water drains out of an outboard when it’s tilted up, the risk of damage from an unexpected overnight freeze is significantly reduced.
4. Easier Access for Maintenance
Outboards shine when it comes time to perform maintenance work on the engine, since they’re mounted outside the hull where everything is easily accessible. By comparison, a sterndrive bolted to the boat’s floor and accessed under a seat makes it tough to reach some components without first removing either the engine or the outdrive. Either scenario means more work, and a bigger repair bill.
Advantages of Sterndrives
1. Wide-Open Swim Platforms
With no engine bolted to the transom, sterndrive-powered boats offer wide-open sterns with full-width swim platforms, which translates to easier boarding access and an unobstructed view when you’re inside the boat.
While some outboard-powered boats use an extended bracket to also allow passengers to walk across the stern between the transom and the engine, the outboard still occupies a big chunk of real estate right in the middle of the platform. And, it still blocks the view – a big consideration when you’re trying to watch a rider on a tube or keep an eye on the kids while they enjoy a swim.
2. Better Fuel Economy
Although today’s sophisticated four-stroke outboard engines have come a long way from the smoky gas guzzlers of the past, sterndrives remain the fuel economy champions. One well-publicized test compared two identical Beneteau Flyer 8.8 boats, one rigged with a pair of Suzuki 200 horsepower outboards and the other rigged with twin Volvo Penta 220 horsepower sterndrives. Running at 25 knots, the outboard-powered Flyer burned through 60 litres of fuel per hour, while the sterndrive-equipped boat burned through only 40 litres per hour. At 30 knots the difference was even more impressive with the outboard boat burning 100 litres per hour compared to just over 50 litres per hour for the sterndrive. That’s a massive difference, especially over the course of a full season.
3. Better Handling
An outboard engine can be a double-edged sword where handling is concerned, and especially if the engine is mounted on a bracket or an extended transom, such as to allow that coveted full-width swim platform. While having the propeller located farther behind the hull can give the boat more bite when making turns, the trade-off is that putting the engine’s full weight that far back can shift the boat’s centre of gravity too far to the stern, and lead to other handling issues. It’s a particularly tricky problem with smaller boats, where the engine represents a high proportion of the boat’s total weight, but it can plague big boats too – and especially if multiple engines are involved.
By comparison, sterndrives escape all of that by being contained within the hull’s footprint, providing consistent, dependable handling without any trade-offs.
A sterndrive’s handling is further enhanced by its typically greater torque. Sterndrive engines tend to be of larger displacement than outboards of comparable horsepower, and torque is a function of displacement. Higher torque contributes to better handling in a number of ways, from helping to plane heavily loaded boats to keeping the boat on plane when running at slower speeds. It’s also a key factor in the sterndrive’s greater fuel economy.
4. You Can Surf
If you like to wake surf, then the decision between a sterndrive and an outboard is no contest at all. Sterndrives with forward-facing propellers, like Volvo Penta’s unique Forward Drive System, tuck the props up under the boat hull thanks to their position on the forward face of the outdrive, and it is this safety enhancement that makes them ideal for wake surfing. By comparison, the traditional aft-facing propeller of an outboard engine represents enough of a safety concern that wake surfing is simply out of the question.
Sterndrives rule for other forms of watersports as well. Whether you’re tubing, skiing or wakeboarding, the action all takes place off the stern of the boat, which makes a clean, clear profile important. More often than not, an outboard motor mounted in the middle of the transom simply gets in the way by blocking the observer’s view or even catching on the tow rope.
So What Will It Be?
The choice between sterndrive or outboard power comes down to what’s important to you as a boater. With their greater power-to-weight ratio, extra cockpit space, ability to be tilted clear of the water and easy access for maintenance, outboards have a lot of appeal – especially for boaters who tend to stretch their season late into the fall.
On the other hand, with their open swim platforms, better fuel economy, predictable handling and the ability to wake surf with Forward Drive models, sterndrives also bring plenty of advantages to the party – particularly for active families who want to enjoy a bit of everything, watersports included.
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