Sailing green on the ocean blue.
[ILLUSTRATION OMITTED]Yacht builder Island Pilot LLC recently completed initial sea trials with its DSe Hybrid 12m luxury motor yacht. This 39.4 ft. long twin-hull yacht combines diesel, solar and electric power, thus the DSe designation. The DSe's primary source of power is solar, with diesel-driven generators secondary and batteries third. The batteries' only functions are to supplement solar power, provide for overnight hotel loads, allow quiet "sunset cocktail cruises" and serve as a buffer.
With sufficient sunshine, the sleek, torpedo-shaped DSe 12m hybrid can cruise indefinitely at speeds up to 6 knots on solar power alone with zero emissions, said Island Pilot. The photovoltaic solar array, mounted on the superstructure up and out of the way over the deckhouse and bridge, provides about 6 kW of electric power. Excess solar array output, not used for propulsion, charges the batteries. With solar and battery, 10 kW of power allows cruising at 7.25 knots for up to four hours.
In the stern of each hull, within sound-deadening enclosures, is a Steyr Motors serial hybrid propulsion system. Steyr calls it a serial hybrid because it is all inline--diesel to electric motor/generator to gearbox to the ZF Saildrive with a three-blade bronze propeller. The propulsion system features a Steyr Monoblock 75 hp diesel engine mated to a flywheel inline 5 kW generator/7 kW motor. It is housed in a bell housing about 3 in. longer than normal.
In electric drive mode, only the electric motor propels the boat. The electric motor/generator is uncoupled from the rear of the diesel, while remaining coupled to the gearbox and sail drive. In diesel mode, the diesel turns the fly-wheel generator coupled directly to the gearbox and the sail drive. The diesel's output of 75 hp, except a portion to generate electricity, is available to drive the boat at up to 13 knots.
At anchor, one or both diesels can be run at a set speed in the generator-only mode to supply up to 10 kW for battery charging and supplying 120 Vac for four-zone air conditioning, cooking, entertainment, hot water, laundry and even optional equipment for making freshwater. The second generator can be started for a total of 10 kW. A pair of 3.6 kW pure sine wave Outback inverters is used.
In the bows are 20 48 Vdc battery banks made up of absorbed glass mat (AGM) True Lead Odyssey batteries from Enersys for a total of 20 kW hours. Energy from these lead-acid batteries is sufficient for up to two hours of quiet running on batteries alone, such as at night. Enersys said the life of its True Lead batteries spans 400 full discharges. Bench tests show many more potential discharges, said Enersys.
The DSe is a plug-in hybrid. While docked, the DSe can be plugged into shore power with a pair of 30 Amp shore power cables. Shore power charges batteries and provides 120 Vac onboard service.
The solar array charges the battery bank via an Outback MX 60 MPPT solar controller/charger. The diesel generator output is controlled by the Steyr hybrid controller, a two-way "black box" controlling the electric motors when running in electric mode and the charging current when the diesels are driving the generators.
Even though the DSe 12m is green, it is far from austere. The great-room deckhouse has a gourmet galley complete with a high-tech refrigerator/freezer with ice maker, radiant cooktop stove, GE Advantium microwave and Splendide washer/dryer. There is an entertainment center with wide-screen LCD TV, Bose Home Theater and KVH TV antenna with DirecTV receiver. Sleeping accommodations include an on-deck master queen berth stateroom and an expansive guest suite.
Piloting the DSe is like any other twin-engine yacht in either electric or diesel mode--by shifting and rudder placement. The DSe features Tecnautic fly-by-wire electronic controls with steering via the knob between the shifter levers. Commands are electronically communicated via CANbus to the gyro-controlled hydraulic helm pump. The gyro autopilot, interfaced with the Garmin 15 in. touchscreen is part of the Tecmarine system. There is also a touchscreen GPS, high-definition radar, digital fish finder, XM radio and weather, and vision chart all from Garmin. Other navigation aids include a Raymarine forward-facing TV camera and Ritchie 4.5 in. navigator compass. The DSe costs about $550,000.
Island Pilot has a smaller, more affordable hybrid yacht in the works as well as a longer, more luxurious one. The smaller Solar Power--Real Quiet, (SPRQ) uses the same diesel-electric serial drive hybrid technology. Using a more efficient single hull with a pair of amas, it is designed to reach similar cruising speeds as the DSe 12m with half the power--for 6 to 7.25 knots in electric solar/battery mode and 13 knots in diesel mode.
Only a 3.8 kW solar array and one Steyr Hybrid motor are needed to power the smaller yacht.
Island Pilot is also working with Steyr Motors to develop a bigger hybrid drive for the 60 ft. DSe 18m. There will be 14 kW of power from the solar array, and it is scheduled to be available in 2010.
Bill Siuru, PhD, PE, is a Diesel Progress field editor based in Temecula, Calif.
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| Title Annotation: | INNOVATIVE uses of HORSEPOWER |
|---|---|
| Author: | Siuru, Bill |
| Publication: | Diesel Progress North American Edition |
| Date: | Dec 1, 2009 |
| Words: | 868 |
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