Sport Boat Power Trend…Going Outboard!

By Capt. John N. Raguso

We’ve discussed this in past columns, but the big outboard trend is starting to evolve from a gradual trickle into a full blown tidal wave. Outboard power in the 300-to-600 horsepower range is starting to find a home on the transoms of more than just go-fast, 40-to-55 foot bluewater fishing boats. Popular sport boat builders like Sea Ray, Cobalt, Formula, Crownline, Four Winns and others are starting to join the big outboard party and it’s making for some interesting power choices for both builders and new boat buyers. .

Evolution

Over the past five decades, inboard/outboard (a.k.a. I/Os) power was the historical choice for the majority of sport boats in the 20-to-32 foot range. For those of you not familiar with these types of engines, this technology marries a traditional automotive engine to a separate outdrive unit that is mounted to the transom. The primary reason for the popularity of inboard/outboard units is that the “directed thrust” of the I/O typically offers more efficiency and maneuverability than the “deflected thrust” of the standard straight inboard setup that uses a rudder to steer the boat while the prop/propshaft never changes direction. This is especially true for single engine applications. Once you morphed above 33-to-35 feet in length, classic inboards were the preferred power choice for the sport boat builders, since the engines were getting significantly larger and the existing outdrive technology was challenged to harness all of this horsepower via the often-fragile outdrive units.

Back in the day, the I/O business was a very competitive marketplace with players like OMC (Outboard Marine Corp, the former owners of Johnson and Evinrude outboards), Yamaha, Volvo and MerCruiser all big stakes players in the game. Each company used their own proprietary home-grown outdrives and typically combined forces with standard gasoline engines manufactured by either Ford or General Motors. As demand began to waiver over the past 15-to-20 years, OMC (bankruptcy) and Yamaha (more focus on outboards) got out of the I/O business. The often cranky outdrives were always the “Achilles heel” of the I/O concept, since they couldn’t tilt totally out of the water like an outboard and projected through a large opening in the transom that was “protected” by a thin rubber bootie that often leaked or ripped, causing many hysterical moments on the water. The engine part of the equation was almost identical to the automotive types and similar to those that most backyard mechanics had worked on for most of their lives, with the exception of a few marinized parts like raw water cooling systems and exhaust headers. Accordingly, they were an extremely popular power choice for many coastal sport boats over the years and continue to be somewhat to this day. But the tide is turning.

Big Outboard Players

The large outboard scene (300 HP and up) consists of a relatively small group of heavy-hitters that most Boats4Sale readers know by name…Mercury, Yamaha and Suzuki. Evinrude closed its doors during the height of the pandemic, as did Volvo’s recent purchase Seven Marine. Honda and associate Tohatsu have limited their largest outboard offering to a 250HP V-6, so they are not part of this discussion.

Suzuki currently offers a V-6 with contra-rotating props that is rated at 300 and 350 HP. Yamaha has recently evolved their popular 425 XTO V8 into a 450 HP version. They also produce a 300 HP V6 that is one of their most popular outboards and they can’t seem to make them fast enough to satisfy demand. Their F350 V8 is still being manufactured, but has had some historical hiccups.

This brings us to the 800-lb gorilla in the room…Mercury Marine. Merc has put its parent company Brunswick’s R&D resources to good use and they totally dominate the big outboard field with their stable of sea ponies that includes the 300 V8; 450 V8 Racing; 350 V10; 400 V10 and the monster 600 V12…and I’m not even including the prior generation’s 300, 350 and 400 HP L6 Verados that are still available.

Why Outboards Make Sense On A Sport Boat

There are myriad reasons why a prospective sport boat buyer might want to consider an outboard as the preferred powerplant for a new ride. The following is a quick list of considerations:

Less Complex

Outboards are mechanically easier than an I/O setup. The motor, drive unit and all of the associated parts are conveniently built into one physical unit that bolts on the back of the boat’s transom.

Safety

With the elimination of a large hole in the transom, an outboard-powered boat is inherently safer, since you are minimizing ways that large volumes of water can ingress into a boat, making the bilge pumps work overtime, draining the batteries and causing the boat to sink. Any foam flotation that the boat builder puts into the hull will now have a positive effect if you ever get into a compromising situation where water is entering the boat.

MORE ROOM ONBOARD- ABOVE DECKS AND DOWN BELOW

When a large chunk of iron and aluminum is removed from the bilge of a boat, it creates volumes of cubic space down under for nautical design creativity. These items include, but are not limited to sleeping accommodations; Seakeeper gyro stabilizers; lazarette under-cockpit storage for water toys, insulated boxes, or whatever; larger fuel tanks for increased range; sun lounge pads; generators; transom entertainment centers; etc.

Faster

Most boats that rely on I/O or straight inboard powerplants are usually limited to two engines, due to beam restrictions and the subsequent mechanical gear delimitations. This is not the case with an outboard-powered sport boat in the 35-to-50 foot range. Some of these hulls can rock three, four or even five outboards on the transom, depending on their size and weight limitations. Many of these 40-to-50 foot outboard-powered sport boats can exceed 50-mph!

Easier To Repower

If you ever decide to get a new outboard engine(s) for your ride, the exchange process is usually uncomplicated and takes the average boatyard mechanic with the right tools less than an hour per engine. It can be as simple as disconnecting the steering cable, fuel line, a wiring harness or two and then unbolting the four-to-six transom thru-bolts that keep the powerplant connected to the boat. I’ve done this myself a few times and can personally vouch for the relative simplicity of the steps.

Bottom line, big outboards hitched to the transoms of supersized sport boats is a trend that is sure to build an even larger groundswell in the coming seasons.