In 2004, Volvo Penta introduced its revolutionary new IPS drive system, which coupled diesel engines to lower units mounted on the bottom of a boat’s hull instead of on the transom. The IPS has been in service for some time now and is finding its way into the production boat market. This new drive system offered substantially increased efficiency, since it enabled builders to achieve desired speeds with smaller diesel engines, and increased maneuverability, since the entire thrust from the propellers could be aimed, as with an outboard engine. Since the introduction of IPS, Volvo Penta has had the market for this drive system all to itself. But that will change in the near future. Cummins MerCruiser Diesel (CMD) has been working on a similar drive system of its own, named Project Zeus. CMD introduced the concept at last year’s Miami International Boat Show, giving those of us in the boating press a glimpse of what the system will offer. Like IPS, Zeus consists of diesel engines matched to drive pods positioned on the bottom of the boat, just forward of the transom. But Zeus differs from IPS in quite a few areas. For instance, the props on the IPS drives face forward like the propellers on most airplanes, pulling the boat through the water. Like IPS, Zeus drives use two counter-rotating propellers on each drive pod, but the Zeus props face aft, pushing the boat like most conventional drive systems do. And Zeus drives mount in tunnels, whereas the IPS drives mount directly on the bottom of the boat. “With the Zeus drives, only the skeg is exposed,” said Rob Mirman, CMD’s Manager of Strategic Planning and the program manager for Project Zeus. “Everything else is in the tunnel, so if you hit an obstruction, only the skeg should break off.” Mirman and CMD have been working with the boat brands within the Brunswick boat group to design these tunnels into the boats, but they also work with non-Brunswick brands. “We have developed mold inserts to accommodate the various boatbuilders we’re working with,” said Mirman. “They don’t have to change their molds, they simply add the inserts to the boats being built for Zeus drives to create the tunnels.” Extensive tests on Zeus-equipped boats have delivered impressive results in terms of efficiency and speed. For example, on a pair of identical 45-footers, one equipped with Zeus drives coupled to 425 hp diesels and the other with twin 500 hp straight inboards, the CMD engineers gained 4 mph in cruise speed with the smaller engines, and 2 mph at top speed. And the ability to gain speed with smaller engines, which obviously burn less fuel, translated into a whopping 30 percent increase in efficiency at cruise, a truly impressive number. This increase in efficiency comes from several factors: first, the hydrodynamically designed drive pods offer greatly reduced drag when compared to all of the hardware associated with conventional inboards. Second, the propellers on the Zeus drives operate parallel to the water’s surface, providing perfectly horizontal thrust for maximum efficiency, unlike inboard props, the inherent down angle of which wastes power. Zeus drives are made out of heavy-duty bronze and stainless steel components for years of reliable service, plus vibration is substantially reduced, and all exhaust exits under water where it will surface far behind the boat. But Zeus drives offer lots more than just efficiency. A host of innovative features built into the system make these drives truly revolutionary. The drive units turn independently of one another in their respective tunnels, providing unparalleled high speed handling characteristics and low speed maneuvering capabilities. “The drives rotate a maximum of 15 degrees inward, and 45 degrees outward,” said Mirman. “The system’s CPU takes factors like the boat’s speed into account during a turn, and rotates each drive unit accordingly.” So if you’re executing a high-speed turn to port, for example, the port drive pod, which is rotating outward (toward the chine) will turn more than the starboard drive, which is rotating inward (toward the keel). The ability to steer the drives independently brings other benefits as well, the most notable being a feature called Skyhook Electronic Anchor. “Every Zeus drive comes with a built-in GPS sensor, an electronic compass, and an inertial measurement unit,” said Mirman. “When you press the Skyhook button and activate that feature, the GPS captures the boat’s position and the CPU then keeps the boat centered within a very tight radius of the initial setting.” This will be a key benefit to cruisers as well as serious fishermen. Think about that— you pull up to your favorite deep-drop spot, press the Skyhook button, and the computer automatically adjusts throttle and drive angle to counter any effects from wind and tide that seek to move the boat off your spot. Just press one button, and the boat stays exactly where you want it. Along similar lines, the Joystick that comes with Zeus drives allows you to dock with unprecedented ease. “Captains will stop using the throttle levers to dock once they see how easy the Joystick system works,” said Mirman. “It provides complete vessel control at a single point.” The Joystick works as a combination of a trolling valve and steering control. You simply push the Joystick in the direction you want the boat to move, and it goes there. When the Joystick is moved slightly off-center, the transmission slips and the props turn very slowly. The farther you move the Joystick from the center, the more the transmission engages and the faster the props turn. If you rotate the Joystick knob, the boat will spin around in place, solely with the thrust from the drives—no bow or stern thrusters are needed. Zeus drives also come with integrated trim tabs built in. “The tabs work automatically and are linked to the boat’s speed,” said Mirman. “The operation of the tabs is optimized for each particular boat.” That means that when the boat is accelerating and climbing out of the hole, the computer might angle the tabs down to provide a little extra lift, and then retract the tabs automatically as the boat settles into a level running attitude. These automatic positions will be set at the factory as the boat is built, but you can also operate the tabs manually, like conventional trim tabs, or offset one tab or the other while operating in the automatic mode. Rob Mirman also points out that the Zeus drives offer enhanced reliability through the use of redundant systems. “We use multiple wires to control the system,” he explained, “so that even if one wire gets damaged, there’s another one to make sure the system will still be able to function.” Zeus also comes with digital throttle and shift for smooth and precise control, and with all of the monitoring capabilities of Mercury’s SmartCraft system. Zeus drives will come in two model designations, the 3500 and the 3800, and will be coupled to Cummins diesels up to 550 hp. The engines can be mounted directly to the drives, or connected via a jackshaft. When the Zeus hits the market this summer, consumers will have yet another power option, and one that brings a high level of efficiency, maneuverability, and high-tech innovation. Contact: Cummins MerCruiser Diesel, www.cmdmarine.com