Sitting at a table with designers and engineers in Miami, I have the sense of a futuristic adventure, akin to NASA in the ’60s or Silicon Valley in the ’80s. Their enthusiasm as they wax on about voltage levels, firmware, energy conversion, and interoperability is contagious. The unlikely source of all this is a catamaran, the Moorings 4300 Electric. In a Caribbean charter fleet (where it has been for the past year), it would blend in with the other bareboats. But its low profile hides a diesel-electric propulsion system that could change the way sailboats are powered. At least, that’s the way the engineers feel about it. “We’re out to change the world,” one of them confides.
The boat is a Moorings 4300, also called the Leopard 43 (owner’s version) by its builder, Robertson & Caine of South Africa. It’s a well-made craft, with exceptionally neat glasswork in both visible and hidden areas. I was impressed by the careful installation of the wiring and plumbing systems and, of course, the innovative diesel-electric drive.
Like other boats from that distant part of the world, this Moorings 4300 was sailed on its own bottom last year to its delivery port, Tortola, BVI. That’s a pretty good shakedown cruise, and there were no significant problems. The test boat had the four-cabin layout suited to charter service, but most private buyers will prefer the three-cabin Leopard version, which devotes one entire hull to a master suite, complete with side-entry bed, sizable head compartment, generous stowage, and even a little office.
The bright saloon is finished with relaxing neutral colors and carefully fitted cherry joinery. There’s a big dining table with space for eight, a good-sized galley, and a small nav station. If you want to spread out paper charts, use the dining table.
It’s an exceptionally fine-handling vessel. Miami’s light winds were not optimum, but it still moved along and tacked satisfactorily. Maneuverability under power is—there’s no better word—awesome. The boat turns on a dime with the props rotating in opposite directions at docking speeds, and it has a turning circle of less than one boatlength with both engines running forward at cruise speed. Shifting is effortless; after all, the throttle/shift levers are electrical switches. There’s full torque to the props even at the lowest speed, which means you can control the boat precisely without revving the motors.
Sound level in the main cabin at low cruise speed was virtually unmeasurable, below 60 dBA. The loudest sounds came from people conversing in the cockpit, 8 feet away. The generator, mounted ahead of the cabin, is in an utterly soundproofed enclosure built by Glacier Bay, and the electric motors aft in each hull are so quiet that they need no soundproofing.
Our test boat carried the standard props for a diesel-powered Leopard 43. Speed and efficiency will improve significantly as the company finds the correct props for the electric motors, which turn more slowly than diesels and have different power curves.
The real news here is the OSSA Powerlite energy system by Glacier Bay. Instead of a conventional setup (two diesels in the hulls and another for the generator) or a system that requires a large battery bank to power the electric motors, the 4300E uses an integrated network that links the 25 kW generator (Mercedes diesel) that powers the twin electric-propulsion motors, and refrigeration, air conditioning, stove, lights, navigation and entertainment electronics, shore adapters and batteries. All the crucial parts “talk” to each other over a Controller Area Network (CAN) bus that was developed for vehicle applications where electromagnetic noise is high. In your car, a CAN bus probably connects engine and transmission control modules and antilock brake systems.
On this boat, if a following sea lifts it and pushes it forward, the motor senses reduced resistance from the propeller and sends that information to the generator, which slows down and produces less current. However, the system is not designed to silently recharge the batteries while under sail; the generator provides direct power to the motors and must be running when the motors are on. But another benefit is the reduced weight (and maintenance) that comes from eliminating two diesels from the back of the boat, not needing extra batteries.
Onboard electrical components are connected to the system at points that provide the type of power they need; 240 volt DC is on the main line between the generator and the brushless DC propulsion motors; matched shore-power controllers, inverters, and chargers make sure that the nav instruments get 12 volts DC; the blender in the galley gets 120 volts AC; the stove gets 240 volts DC; and the supply exactly meets the demand. Plug into any kind of shore power you wish, use any appliance and disconnect at will—the system adapts and optimizes.
All this actually works. The test boat has survived a year in Caribbean charter service, a fine test for devices that must be foolproof. There are some quirks at this stage of development; for example, the tachometer is inadequate and badly located. These are small items and easy to fix.
It’s a bit ironic that a futuristic concept like the Powerlite system debuts on an ancient Polynesian concept that’s pushed about by wind. Who knows if this will change the world? What I do know is that the Moorings 4300 Electric’s diesel-electric system is a clever, quiet, more environmentally friendly way to power a boat, and it’s available right now.
Price: $475,000 (base, FOB Cape Town, South Africa) includes sails, windlass, inverter, and hard top bimini.
Builder: Robertson & Caine
Designer: Simonis-Voogd Design
Construction: Hull is vacuum-bagged and balsa-cored; hull/deck joint is secured with adhesive, then bolted and glassed to the bulkheads.
Pros: Fuel-efficient, environmentally friendly, nearly silent-running motors. Reduced weight and maintenance from subtracting two diesel engines from the sterns.
Cons: Tachometer design and location (minor). The first model of such a new technology can possibly have glitches.
LOA — 42'6"
LWL — 37'9"
Beam — 22'9"
Draft — 4'3"
Displacement — 19,030 lbs
Sail Area (main and jib) — 1,238 sq ft
Power — 25kW diesel generator with two 20-hp electric motors
Tankage Fuel/water/waste — 95/206/45 gal
Electrical — (1) 95-Ah starting battery, (3) 180-Ah house batteries
Displacement-Length ratio — 158
Sail Area-Displacement ratio — 27