The motor/generator operates in four modes. First, as a backup to a more conventional starter, it can crank the diesel. Second, upon receiving appropriate signals from the HCU, it can serve as a generator that, according to Steyr, is considerably more efficient than either a typical genset or an engine-driven alternator. Third, it can propel a small vessel at an all-electric speed of approximately 5 knots (see "Sea Ray Goes Electric,") once it's uncoupled from the diesel flywheel. And fourth, again upon receiving another signal from the HCU, it can momentarily boost acceleration during primary-diesel operation, then subside into generator mode to charge the battery bank.
Streitner adds, "We are working on a generation two version right now with a generator power of 20 kW instead of 10 kW and speeds we think will go from 8 to 10 knots for a small boat."
How much does a Steyr Motors Hybrid cost? The 250-mhp turbocharged/intercooled Steyr MO256H45 that powered our Sea Ray test boat, for example, retails for approximately $37,610 with HCU, hybrid solenoid switches and relays, and SCC dashboard LCD. Drop the hybrid package and the diesel alone (with no marine gear) will set a buyer back about $22,513.
What does your money buy? The Steyr diesel—all by itself—offers some pretty unique features including two-stage fuel-injection that reduces emissions, accommodates fuels other than diesel (from JP 8 to cooking oil), and obviates the need for extensive high-pressure piping associated with common-rail diesels. There's also a robust monoblock that combines a cylinder block and cylinder head in one high-grade alloy cast-iron piece and a sophisticated cooling system with extra galleries and passages designed to maintain acceptable engine temps.
Why add a hybrid option to such an impressive array? According to Streitner, a Steyr customer with a penchant for regular, early-morning departures from his marina wanted a Steyr-equipped runabout he could operate without disturbing either his neighbors or the wildlife he liked to observe near his waterfront home. The quiet, zero-emissions capability of the Steyr Motors Hybrid was the upshot.
"He is loving it," adds Streitner.
For more information on Steyr Motors, including contact information, click here.
This article originally appeared in the January 2009 issue of Power & Motoryacht magazine.