Outboard Advantages | Boating Magazine

Outboard Advantages

Runabout power may be shifting to the outboard. Will it change the game?

Outboard-powered bowriders are making a comeback, and the reason is colored green. As in the shade identified with both eco-friendliness...and money.

Once nearly extinct in the entry-level bowrider market, outboards find themselves back in demand, thanks to stricter emissions laws that necessitate stern-drive engines be fitted with fuel injection and exhaust catalysts in order to make the cleanliness grade. This tightening of the emissions belt, and the subsequent price bump that comes with it, means the low-horsepower stern-drive engine is about to be a thing of the past — and that good ol’ outboard is looking more and more attractive by the minute.

Ever wonder what the differences are between a boat equipped with an engine that resides below the sun pad and one equipped with power that hangs on the transom? We did, so we decided to hit the water with a pair of nearly identical Ebbtide 188s — one sporting an outboard, the other a stern-drive.

Here’s how they compared.

Performance Breakdown
For the purposes of Boating’s test, one of the 188s sported a 115 hp Evinrude E-TEC outboard, the other a 190 hp MerCruiser 4.3-liter stern-drive. Obviously, that’s not an apples-to-apples comparison, but it’s the reality of today’s market.

The aforementioned emissions laws have pretty much done away with the availability of the once-popular 135 hp 3.0-liter stern-drive. While the days of the carbureted 4.3 may also be numbered, there are simply more of them in inventory, ensuring their availability in the near future.

Despite what seemed like an obvious disadvantage on paper, the outboard proved a worthy competitor, part of which can be attributed to its significantly better power-to-weight ratio. Coupled with an Alpha drive, the MerCruiser 4.3 tips the scales at 865 pounds; by comparison, the Evinrude 115 weighs only 390.

Coming onto plane, the outboard came up and over the hump in 3.6 seconds, the stern-drive in 4.8. While the stern-drive’s greater torque likely helped it post the better time to 30 mph (seven seconds), the outboard still kept things close, hitting the mark less than one second later. The stern-drive’s added horsepower truly resulted in a clear advantage only at top speed. The 115 hp outboard peaked at 43 mph, while the 190 hp stern-drive continued on to finish just a fraction shy of 48 mph (47.9).

Torque is worth considering when you compare the two forms of power. It’s directly proportional to engine displacement, meaning the 4.3-liter stern-drive has a decided advantage. Torque has practical benefits, like allowing the boat to stay on plane at lower speeds or muscling a skier out of the water in a deepwater start.

Outboards are presumed to be more fuel-efficient at low speeds and stern-drives more efficient on the top end. Our test proved half that statement. Looking at the fuel-flow data of our two test boats (as well as results of several additional tests with similar engines), the outboard burned 30 percent less fuel at 5 mph. A big percentage, but a small difference in actual fuel burned. If you idle often, it results in savings. At 31 mph, the outboard consumed 7 gph, while the stern-drive burned 7.6 gph at 32 mph — nearly a dead heat. At its peak 43 mph, the outboard burned 11.1 gph for 3.79 mpg compared with the 48 mph, 2.77 mpg stern-drive’s 17 gph.

Outboard vs. Sterndrive

Outboard vs. Sterndrive

Boating Magazine

Lay of the Land
An outboard opens up more cockpit space. By eliminating the need to place the engine within the hull’s confines, manufacturers are typically able to expand the boundaries into an area otherwise occupied by a sun pad or motor-box enclosure.

The flip side? Tucking a stern-drive out of sight allows for that spacious sun pad, as well as a full-width, undivided swim platform across the stern.

Interestingly, Ebbtide keeps almost the complete stern-drive-style layout when switching to the outboard. The most noticeable difference with the outboard version is the half-moon chunk taken out of the 6-foot by 2-foot-6-inch sun pad.

Below, the area taken up in the stern-drive version is divided between the motor well and a rectangular storage area in the center, flanked by large, divided stowage areas to port and starboard. By necessity, the outboard’s swim platform is divided into two 14-square-inch platforms. That makes it more difficult to gear up for wakeboarding or skiing, and it offers tighter confines when reboarding using the starboard-mounted swim ladder.

Outboard vs. Sterndrive

Outboard vs. Sterndrive

Boating Magazine

Maintenance and Practicality
As to engine access, the outboard is the obvious winner. Pop off the cowl and you’ve got 360-degree access. The larger stern-drive engine is often sandwiched into tight confines, although basic maintenance points are generally within reach. But for any form of serious maintenance, the outboard is superior. We’ve seen stern-drive engines pulled completely from the boat for serious repairs, requiring time that significantly adds to the repair bill.

Also, an outboard can be used through winter’s cold without fear of freezing, since its cooling system drains completely after every use. Even basic winterization is different. A quick survey of northern dealers revealed an outboard winterization with gear lube change costs roughly $65, while the comparable stern-drive bill is around $120. An outboard’s simplicity also prompts more owners to do the job themselves. (The E-TEC we tested can even “self-winterize” at a turn of the key.)

Outboard vs. Sterndrive

Outboard vs. Sterndrive

Ebbtide

Other considerations? Stern-drives must be removed from the boat to service bellows gaskets and u-joints; outboards are self-contained with fewer parts. Unlike an outboard, a stern-drive can’t be tilted fully out of the water, a particular concern if you keep your boat in salt water. Outboards are built to self-drain the raw water used in cooling them, meaning an outboard is typically less prone to internal corrosion. An outboard also offers one big advantage over time. It’s easy to repower an existing boat by simply hanging a new engine on the transom. Even trailering favors the lighter-weight outboard, because it effectively allows you to haul more horsepower should your tow vehicle have limited capacity.

On the flip side, stern-drives provide a clear transom. The view aft is free of obstruction, and there’s less worry of snags when fishing or swimming off the stern. The full-width swim platform also makes for easier gearing up and reboarding. Stern-drives tuck the motor away in an enclosed housing, which dampens much of its noise, although this was more of an advantage in the old days than it is with today’s quiet outboards. Horsepower for horsepower, stern-drives remain the less expensive engines to buy. On the Ebbtides we tested, the 190 hp stern-drive can be had for about $600 less than the 115 hp outboard.

Outboard vs. Sterndrive

Outboard vs. Sterndrive

Ebbtide

And the Winner Is...
Obviously, there’s no clear favorite. Each power option offers strengths that apply to individual buyers, and each features drawbacks that will do the same. One thing is certain. As emissions laws tighten, you may need to bone up to choose between outboard or stern-drive on your new runabout.

The Options

Outboard vs. Sterndrive

Outboard vs. Sterndrive

Four Winns

Four Winns H180 OB
LOA: 17'4"
Beam: 7'6"
Displacement (lb.): 2,140 to 2,290 (w/ engine)
Fuel Capacity: 24 gal.
Max Horsepower: 150
Notable Feature: Options can slant toward fishing (trolling motor) or towing (tower, removable ski pylon).

Outboard vs. Sterndrive

Outboard vs. Sterndrive

Glastron

Glastron SSV 170
LOA: 16'11"
Beam: 7'4"
Displacement (lb.): 1,200
Fuel Capacity: 23 gal.
Max Horsepower: 115
Notable Feature: Unique layout of dual swim platforms recaptures some of the space lost to the outboard and motor well.

Outboard vs. Sterndrive

Outboard vs. Sterndrive

Hurricane

Hurricane 187 SD
LOA: 18'10"
Beam: 8'5"
Displacement (lb.): 2,260
Fuel Capacity: 52 gal.
Max Horsepower: 200
Notable Feature: Livewell with pump is standard equipment. Add the optional gas grill, and you’ll be cooking the catch of the day.

Outboard vs. Sterndrive

Outboard vs. Sterndrive

Tahoe

Tahoe 215 CC
LOA: 21'2"
Beam: 8'6"
Displacement (lb.): 2,200
Fuel Capacity: 45 gal.
Max Horsepower: 200
Notable Feature: Center-console design, rod holders, fore/aft fishing positions and aerated baitwell give it serious fishing credentials.

Outboard vs. Sterndrive

Outboard vs. Sterndrive

NauticStar Boats

NauticStar 230 DC
LOA: 23'0"
Beam: 8'6"
Displacement (lb.): 2,700
Fuel Capacity: 66 gal.
Max Horsepower: 250
Notable Feature: Optional outboard swim platform lets skiers/wakeboarders gear up away from the prop.

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