Ever since there have been outboards, inboards, stern drives, and jet drives, boaters have been arguing about which is best—and now, pod drives are part of this same discussion. But recent advances have vigorously shuffled the deck, and this topic is worth looking at with a fresh set of eyes.
First off, let’s point out one inarguable fact: which of these power systems is “best” depends to a huge extent on who you are, what kind of boat you want, and what type of boating you do. As such, it’s impossible to make a blanket one-size-fits-all statement answering this question. Instead, you need to consider the plusses and minuses of each power system, then make a decision based on the facts as you see them. Which, of course, is impossible to do if you don’t understand all of the facts. So let’s dig into each.
First, the plusses
Modern outboards have a long list of advantages. Start with their new-found reliability; while you could count on those old-tech two-strokes to break down with depressing regularity, these days, it’s common to go for five or six seasons without lifting a finger beyond regular maintenance. Then consider their comfort factor. Today’s outboards are smoke-free, quiet, and don’t create nearly as much vibration. They also tend to have excellent efficiency, even while attaining speeds in excess of other power systems. And a new option with outboards is joystick control, which greatly enhances dockside maneuverability. Finally, if an engine needs replacement it’s a far simpler job than replacing any other type of power source.
Inboards are also comfortable to run, and at least on larger boats, tend to make a bit less noise than some other options. One often-overlooked advantage they have over some power systems is weight distribution. All other things being equal, placing the weight deep in the boat’s belly often enhances the ride and increases a boat’s stability. On top of that, the sky’s the limit when it comes to horsepower range. Plus, you also get to choose between gasoline or diesel.
Pod drives have all the advantages of inboards plus a few more. The articulating drive systems make handling second to none—with a pod drive joystick at your fingertips, it’s easier to dock your boat than it is with any other power system. Efficiency goes up as compared to inboards (remember that pod drives provide angle-free thrust), sometimes by as much as 25 percent. And the elimination of shafts and the required shaft angle allows designers to gain cabin space, since less is needed for the engine compartment.
Stern drive power systems, like outboards, have gotten a handling boost from joystick integration. And, of course, they give you the ability to change your draft and adjust running angle via trim, when necessary. While they don’t provide as big a weight distribution advantage as inboards, they do have a leg up in this regard compared to outboards. And do-it-yourselfers often favor stern drives for the easy engine access, and automotive-like familiarity of the powerplant.
The jet drive advantage is obvious: with no propeller spinning beneath the boat, you never have to worry about the propeller getting damaged—or doing damage, specifically, to a person. Though truth be told prop injuries are extremely rare, it’s still a possibility that many people want to eliminate. That makes jet drives a favorite of many new boaters, particularly those buying small family runabouts.
Then the Minuses
Outboards may have come a long way, but as they’ve progressed, prices have gone up accordingly. A modern 250-hp powerplant will cost you upwards of $20,000, while a new (gasoline) stern drive or inboard package of that size can cost between $5,000 and $10,000 less. And today’s outboards are extremely technologically-advanced—forget about doing much more than an oil change without a visit to the dealership. While outboard joysticks are an awesome new development, generally speaking, they don’t handle as well as pod drives. Your power choices are limited in size, as well, since mass-produced outboards top out at 350 horses (though Seven Marine does make a limited-production 557-hp outboard, from a marinized 6.2L Cadillac engine). And with very few exceptions, diesel is not an outboard option.
Inboards are the only power system on the water today with drives that don’t articulate; they still depend on rudders for steering. As a result, their handling (except dockside, when opposing a pair of twins) is at the bottom of the list. The same is true of draft; other than sailboats, no boats require more water under the keel than straight inboards. Inboard-powered boats also suffer from more drag than the others, which translates into less speed and efficiency. And an inboard eats up a lot of space in the boat, minimizing the room left for the cabin.
Pod drives are an expensive option, though they’re usually found on larger boats, where the percentage of overall cost isn’t out of line. Many people are scared off by the idea of having those large holes in the hull for the drive units. Getting the drives serviced can also be expensive, and time-consuming, depending on where you’re located. Finally, remember that a boat has to be designed specifically for pods—you can’t repower with them, and when existing boat models are modified to carry pods the builder may encounter additional design costs, which will probably be passed on to the consumer.
Stern drives are notorious for their maintenance issues. The boot and outdrive systems, in particular, tends to require a lot more attention than simpler drive systems. And in some cases, a lack of maintenance (particularly with the boot) doesn’t cause a mere trifling breakdown— it can sink the boat. Stern drives also eat into cockpit space in some boats (especially on smaller models) because they may require a raised motor box. Many single-screw stern drives wander quite a bit at slow speeds and require constant steering. And while many marinized engines currently on the market are familiar to do-it-yourself mechanics, this is changing as some marine manufacturers have started designing their own engines, instead of adapting those made for automotive use.
Jets have a number of drawbacks weighing against their big prop-free advantages. There’s a significant loss transferring power into thrust, which makes jets less efficient and slower in the mid-range. This also means that in many cases, jet-driven boats struggle to get onto plane unless the throttle is buried. They also tend to be very loud. And handling at slow speeds, which can range from great to atrocious, requires a lot of getting used to.
Do the Math
So, after all that, which system will be the best for you?
Here are a few generalizations: people who like to go fast, demand reliability, and run boats 35’ and under often prefer outboards. Those buying larger boats and those who want diesels commonly choose either pods or inboards, and pod drives have been cutting into this market segment with a vengeance—especially among people who like the uber-awesome handling and maneuverability. On much larger boats, however (say, 60-plus feet) larger straight inboards still rule the roost. Stern drives still have a big following thanks to their lower cost and auto-like familiarity, particularly on runabouts and small cruisers, where the motorbox may actually be an asset—once it's renamed "sunpad."
And, of course, there are some niche-boat exceptions. When it comes to serious ski boats, for example, diehards demand the small, flat wakes produced by single-screw straight inboards. Entry-level runabouts are usually powered by stern-drives to take advantage of their lower price, though outboards are currently staging a come-back in this segment; the cost of newly-mandated stern-drive emission control equipment evens out the playing field a bit. Then there are river-running boats, which need to use jet drives or risk perpetual prop damage.
Boaters tend to be opinionated folks, and there’s a good chance you had a “best” power system in mind before you even read the first sentence of this article. But times have changed, and like it or not you’ve been dealt a fresh hand. So before you buy a new boat, assign each one of these power system plusses a value between one and 10, depending on how important it is or isn’t to you. Then assign each of the minuses a negative one to 10. Finally, do some simple math—and you might just discover that understanding the positives and negatives of modern power systems has given an old argument a new conclusion.