America's Definitive Marine Engine Magazine
Over time Azipods have proven reliable and trouble-free so long as they are maintained appropriately. Here then follows some thoughts on how to get the job done properly, either by Doing-It-Yourself, or by managing the work done by technician tasked with the job.
Seems like only yesterday when pod drives were only a twinkle in the eye of marine propulsion engineers. But today azipods have proliferated to the point where all the major players offer one, including Volvo-Penta's IPS, Cummins MerCruiser Diesel's Zeus, as well as Yanmar Marine and ZF Marine. Pod motors hang on the stringers of hundreds of models of boats around the world. That said, like any mechanical device, they require preventative maintenance to keep them running at peak performance. Even so, there's significantly less maintenance than a conventional propulsion system fitted with a propeller shaft, coupler, Cutless bearing and the stuffing box. And don't forget, because of joystick control your boat doesn't have a bow thruster and the attendant maintenance chores. So exactly what steps are involved, you might ask? Here's a run down.
First comes routine maintenance. You already know a diesel requires clean air, clean number 2 diesel fuel, adequate coolant and fresh lubricant. So every day before firing up main propulsion, or when refueling, take the time to check the diesel engine's vital fluids. In other words, pull the crankcase dipstick; check the sea strainer and coolant level and drain the fuel/water separator. On the pod drive proper, check the steering actuator and trim tab fluid levels. Note the level in the gear lube monitor and check the transmission fluid level.
At around 100 hours check and or replace the sacrificial zincs; check the sea strainer (clean if necessary); check the air cleaner for restrictions; check/adjust the sea water pump's drive belt and check electrical connections. It's also important to inspect the battery connections and the battery electrolyte levels. On the pod drive proper check the steering back up pump fluid level. Change the engine oil and filter. Know that according to Cummins MerCruiser Diesel, using synthetic oils (engine or drive) does not increase the oil change interval.
Azipods are robust. That said their most common problem lies with not maintaining the corrosion protection. While azipod housings are corrosion-resistant bronze, rather than an aluminum alloy like on a stern drive, it remains vital to maintain the anodes. Check them the same as zincs on a propeller shaft. Get in the water snorkel down for a proper look-see. Replace anodes annually, or sooner, with the correct alloy. Know that most pods use aluminum anodes, not zinc. Should anodes exhibit a short life span, check for stray current, a problem most likely emanating from the marina shore power. Read the owner’s manual. Depending on the brand, the pod might have internal anodes snuggled away out of easy sight.
At the one year mark, or about 500-engine hours, the checklist grows more intensive. Diligently inspect the sea water pump; the drive belt tensioner; the drive belts; flush the after cooler; flush the gear oil cooler, flush the heat exchanger; check the air cleaner; check the engine mounting bolts; check the vibration isolators.
And the last item for routine maintenance, whenever the boat is hauled for bottom paint, or if you're paying a diver to scrape off barnacles, remind the diver to take a close look at the propeller blades to make sure the blades are not nicked or gouged.
Scheduled maintenance follows a similar pattern. After 25-hours replace the transmission fluid. Volvo-Penta warns: "Don't make the mistake of exceeding 30 hours." At the 250-hour or one-year mark, whichever comes first, change the transmission and drive leg gear oil and also steering and trim tab reservoirs. On models fitted with a steering fluid filter, change it (drain out old, refill with new). Replace any sacrificial zincs that have corroded away to less than 50-percent of their original size.
Once a year, or every 500-hours of engine operation, (Read: Haul-out) remove the propeller. Remove any fish line that may have spun up into a ball. Ignored it will worm its way into the prop shaft seal, cut it and cause an oil leak. As the gears twirl they create high pressure and squirt out oil out a damaged seal, leaving a vacuum inside the gearcase that sucks in seawater. Disaster. Lubricate the propeller shaft splines, reinstall the wheels and torque the propeller nut. On the drive check the exhaust system connections for damage or leaks.
Change vital fluids as per the maintenance schedule, using nothing but the recommended gear oil, or oils. Volvo uses just one oil, while Cummins uses three different oils in its Zeus drives. Maintenance schedules vary somewhat among pod builders. Essentially the dictum boils down to changing fluids either annually, or every 250-hours of operation, whichever comes first. Best done at haul out, drain the oil by gravity, a process that evacuates nearly all the dirty oil. A pump leaves too much dirty oil in the gear case. Inspect the drained oil for signs of water infiltration. For greater peace of mind, consider having the oil analyzed. Oil analysis runs about $200 and is cheap insurance for the simple reason finding a bad propeller seal early-on saves thousands of dollars in repairs. Similarly, changing the motor oil at least annually, even if you don’t hit the hour limit, is a wise investment.
Most pods require service after a short break-in period at 25, or so, engine hours. That means a haul out to remove the break-in lube and replace it with the normal lubricant. Make sure to do this, and if buying a used azipod powered boat, make certain the original owner did it. Running an azipod for too long on break-in oil can shorten the life of its gears, shafts and bearings.
Maintain a sound, anti-fouling strategy. Azipod freshwater intakes and engine exhaust port are a beckoning, happy home to marine growth. Keep them out with Propspeed, or another anti-fouling paint, formulated for underwater metal protection.
Inspect the cooling system for hoses that may have become brittle and any hose clamps that have comes loose due to vibration or corrosion. Look for damaged wiring and loose electrical connectors. Inspect hydraulic system fittings and hoses for damage and leaks.
You should also know that depending on the brand, and whether or not you opted for an extended protection plan, many of the procedures are performed by a marine technicians at no cost. Similarly, create a paper trail, saving all of the work orders and receipts. Finally, it's good practice to keep a maintenance log. It can help troubleshooting if anything goes wrong. And more importantly, it can boost resale price.