Pod access aboard the Riviera 43 is through the cockpit sole.

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Pod drives have been widely available only since 2007, yet they have the market awhirl. Sabre Yachts, for example, first offered pods in 2008 as an option over straight shafts in the 42-foot express cruiser. The company has built exactly one 42-footer without pods since, versus a dozen boats with the pods option and another 50 of the new, pod-only 42-footer. “The noise and smell from a diesel goes away with pods,” said Bentley Collins, Sabre’s vice president of marketing and sales, “and with joystick control, you don’t have to worry about crashing into the dock.”

Pods also increase fuel economy and decrease vibration. But now that both Volvo Inboard Propulsion System and Cummins MerCruiser Zeus drives have been spinning beneath boats for more than five years, it’s time to assess the cost of ownership of pods versus conventional shafts.

“There is definitely more maintenance with pods,” said John Siebert. His company, Siebert Yacht Management commissions and maintains most new Sabre boats delivered to Palm Beach County, Florida, giving him considerable experience with Volvo IPS drives on Sabre’s 38- and 54-foot models and with Cummins Zeus drives on Sabre’s 42- and 48-footers, as well as those same hulls with conventional shafts.

To start with, Zeus and IPS boats have to be hauled after their first 25 engine-hours. “Cummins says you don’t have to haul, but it takes a lot more time to suck that heavy oil out than to just drain it from the bottom,” Siebert said. Volvo doesn’t offer the option of in-water service. “Plus, when we haul the boat, we’ll catch problems a diver won’t see.”

“For those first 25 hours, we use a break-in lube,” said David Fessenden, a marine applications engineer with Cummins Atlantic. “That smooths out some of the minor gear asperities and grinding marks, improving the life of the gears.” After break-in, pods are serviced every 250 hours or 12 months, whichever occurs first.

“Take the props off, grease the shafts, and check the seals,” Fessenden said. Zeus propeller shafts use a double-lip seal. If the outer seal is damaged by debris, fishing line or rope, only the inner seal separates the pod’s innards from seawater. “Look for signs of corrosion.” Zeus has two zincs attached to each trim tab. Volvo has one zinc hidden, but accessible, on the drive itself. “If you seem to be going through zincs quickly, call an electrician,” Fessenden warned. Use Volvo or Cummins zincs too, which aren’t zinc at all. Cummins uses aluminum-gallium anodes to best protect bronze drives.



On Cummins drives, standard-equipment MerCathode system anodes emit a tiny electrical charge opposite the damaging electrical currents that normally flow through metal parts in seawater, actively protecting pods from galvanic corrosion. Volvo’s Active Corrosion System, which is standard on IPS 800 or larger drives, is similar. Those anodes shouldn’t dissolve like zincs do, but both systems should be checked annually.

“If your zincs are gone, your warranty might be gone too,” Siebert said, so all his clients’ boats with pods are cleaned and checked monthly by a diver. Cleaning also maximizes efficiency of the pods’ contrarotating propellers.