Cheetah, the 55' Dix-Harvey catamaran powered by E motion hybrids is now cruising the Caribbean. After several thousand miles of island-hopping, owner Bill Choice has reported back on the performance of his hybrid drive from Electric Marine Propulsion.
He's full of praise for the system, noting its responsiveness, maneuverability, regeneration, reduced maintenance and fuel efficiency.
The DH550 cruising cat started life as a design commission received by Dudley Dix from catamaran builder Philip Harvey. Phil drew the hull concept, Dudley did the design and Bill was given the freedom to design the interior himself. |
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Construction is a further development of the radius chine plywood concepts that Dudley has drawn since the early 1990's.
Cheetah was built in Trinidad, and during construction, responsibility for completion was transferred to Peter Laine. He finished the boat at his yard in Chaguaramas, on the southern coast of Trinidad's northwestern corner.
Starting from Trinidad and Tobago, Cheetah has visited St. Vincent, Mustique, St. Kitts, Nevis, Guadalupe, Martinique, Les Saintes and St. Bart's. During a stopover in St. Lucia, Choice wrote down his impressions of the system in an email to Electric Marine Propulsion CEO Dave Tether.
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| Cheetah anchored off the beach in the Tobago Keys |
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| Running downwind off Antigua |
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| Sprinkled with mahogany sawdust, the 16 kw motor hangs down between the rails from a mounting frame. |
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| Salon beckons for late-night dining |
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| Bins in central cockpit behind mast stow lines neatly. |
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| Just after launch into Chaguaramas Bay. High bridgedeck clearance reduces wave slap. |
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| Peter Laine's yard borders the large Power Boats complex in Chaguaramas. |
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Dave:
Just a brief summary of our experiences with the Electric Marine Propulsion system aboard our new 55' catamaran, Cheetah. We have now sailed several thousand miles among the islands of the Eastern Caribbean in all sorts of sea conditions and have found the system to be excellent. The advantages over a traditional diesel motor driven catamaran are many, and we have begun to fully appreciate our decision to go electrical.
Quickly, here are the things that we appreciate the most:
1. The electric motors are quick and extremely responsive and always available without starting diesels. It is so much easier navigating in tight quarters in a marina or when docking. And they are quiet, allowing the offwatch crew to sleep without noise, heat or diesel smells. Best of all, they require no maintenance.
2. Our two 16 kw gensets are forward in individual lockers that are enclosed for sound, but easy to access for maintenance. We opted for two gensets instead of one for two reasons: redundancy and fuel efficiency. When we are at anchor and charging batteries or motoring at around 6 knots, we use only one generator. When we want to motor faster, the second genset kicks in. Most cats our size would have "3 diesels" to maintain, two for propulsion and one for 110 VAC house loads such as A/C when not in a marina.
3. The AGM battery bank has been maintenance-free along with the associated equipment: cross charger for the house bank, inverter and battery charger.
4. Regeneration is a real plus for this system, and we did not appreciate its importance in the beginning. On Cheetah we can feather our props or leave them engaged for regeneration. When we make a passage, regeneration can fully maintain our batteries and cover all house loads unless the wind is very light and we are choosing to not motor. In regen mode the boat is slowed by the props by about a knot or so in 15 knots of wind; not much for a cat that does 12+ on a reach in this much wind. But being ex-racers, we have the option to feather our props at any time and let her fly.
5. System management has been much easier than we expected. There certainly is a learning curve, but you do not need to be an electrician to safely manage things. Monitoring battery status and electric motor performance is simple with our current meters and should be a snap with the new EMM [energy management module] when we install it. Best of all, the only parts that require regular maintenance are the diesel generators, and since they don't run as much as on a traditional catamaran, maintenance periods are further apart - and overall fuel consumption is much less.
6. Not to be overlooked, we have really appreciated the full support of EMP and your personal attention and responsiveness. We know this is a new and evolving technology, but we would not hesitate to go this way again. The advantages are too many. And when you just look at the pieces -- batteries, electric motors and diesel gensets have been around a long time; and diesel electric propulsion is used throughout the world in ships and trains and buses and many other applications. I think diesel electric propulsion for sailboats is certainly the wave of the future, and EMP is leading the way.
I would recommend your system to anyone building a new boat or considering an upgrade and would be pleased to serve as a reference.
Sincerely,
Bill Choice
Yacht Cheetah
Cruising the Caribbean
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| Dawn breaks over Cheetah's bow, somewhere in the Caribbean. |
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| Batteries are stowed vertically for easy access, with shore charger above. Blue box is Victron charger used as DC-DC converter. |
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| Central helm with wheel and dual throttles. |
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| On a mooring in the British Virgin Islands. |
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| The E motion hybrid system provides power for Cheetah's numerous house loads as well as for the propulsion motors. |
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