The quiet revolution

As electric cars are appearing on the road in greater numbers, so will electrically-powered boats form a greater presence on the water.

You will be able to operate your boat at a fraction of the cost, have maximum torque through the whole rev range and ride in silence with no emissions. Marinas and waterways will be cleaner and quieter; and your guests will enjoy canapes in the cockpit while underway without the fumes and noise of conventional engines. Owners will be safe in their social responsibility, knowing they are doing their best by the planet. This could be reality with the emergence of electric boats.

In recent years the automobile industry has produced various hybrids and fully electric cars – a huge breakthrough after relying on conventional fossilfuelled power for more than a century. Now, electric engines are humming their way quietly into the marine industry. Marine hybrid propulsion has been around for a while but has been limited by lack of workable energy storage. With major improvements in this field, the performance and usability that we take for granted with conventional engines will soon be reality for electric propulsion.

Electric motors have only three moving parts and are 80 to 90 per cent efficient in converting energy into work; petrol engines are only about 25 to 30 per cent efficient, and modern diesels are up to 45 per cent efficient. However because the torque curve for an electric motor is flat; ie, the electric motor is running efficiently through a much wider rpm range than its internal combustion (ICE) counterpart, it delivers efficiency gains through a wider range of rpm. This means a gearbox is unnecessary – so no transmission, no oil filters or air filters, no transmission oil to change and discard.

Electric motors have no need for saltwater cooling, eliminating the need for through-hull fittings, sea cocks, sea strainers and the noise, smell and waterline grunge associated with exhausts. The transformation to electric will be like upgrading from a two-stroke to a four-stroke outboard: quieter, cleaner and with better fuel mileage.

Guests will enjoy the quiet operation which is also great for cocktail cruising, whale watching and snorkelling – and what appeals to guests, sells. The clean, quiet comfort that will soon be widespread in electric tenders may well inspire a revolution to electric power throughout the yachting industry.

At Kit Carlier Design we have just launched Chimera, our first limousine concept using this technology. Inspired by the gentlemen’s racers of the 1920s and 1930s, the 14.5m limousine blends classic design elements and

contemporary styling with an ultra-modern propulsion and electronics package.

Chimera will successfully meet the increasingly stringent regulations around global emissions but, more importantly, she will be part of the drive to design vessels that perform well using clean, sustainable energy.

To achieve that, Chimera has an efficient hull and stream-lined top and is built from strong lightweight materials. Her speed and usability are not compromised by running on electric power.

As a limousine, Chimera will provide luxury commuting from a superyacht or lakeside property to a marina or perhaps operate from a waterfront hotel to the airport. Passengers will be seated comfortably in her palatial interior while their chauffeur/ helmsman drives from a forward, port helm station. This is a styling cue taken from a bygone era when chauffeurs drove sans roof with passengers in the rear.

The interior’s clean styling features limousine-style opulence. Entertainment, lighting and access to wireless communication and Bluetooth are available throughout the limousine, via touch screens located from the helm to the main cabin. Chimera’s app allows passengers to access the vessel’s facilities from their seats, using smart devices.

Chimera offers three propulsion options: conventional common-rail turbodiesel engines, a diesel-electric hybrid and a total electric package.

The latter option is still under development. The team is working on a Tesla drive system using two 416hp (310kw / 600Nm torque) motors. Each motor is coupled to a Tesla 85kw battery pack; this gives the Tesla model S a range of approximately 480km. It will use the supercharged charging system for rapid charging, using Tesla’s proven technology.

ONBOARD WITH CHIMERA

When guests and crew come on deck in the morning, ready to play,

the limousine tender will be fully charged, having been plugged into the mothership’s charging system overnight when there is little load on the generators – it’s basically charging for free.

Fully charged, the limousine has a range of more than 80km. It will be launched and ready to go. As with electric cars, the dash has gauges which display the state of charge on the touch-screen controls – the equivalent of a car’s fuel gauge.

Amp gauges will monitor the motor’s electricity draw which easily translates into available range, also displayed to the driver.

The versatile, onboard charging allows for charging at any time, regardless of the battery’s state of charge. Whenever the tender is idle, for example at the dock or alongside its mothership, it can be plugged in and recharged, without the mess of diesel.

HOW FAR WILL IT GO?

Initial calculations give Chimera a conservative range of 43nm (80km) at 38 knots. A full charge at either end would take approximately seven hours using a conventional charging unit, but Tesla’s super charger could reduce this to one hour. A genset would allow for greater range.

Limousines like Chimera usually operate with fairly short trips so charging at either end is fairly easy.

The beauty of this symbiotic relationship is that superyachts generate large amounts of power so that their many amenities are always ready to run, but much of this is wasted. A tender limousine charging overnight in the mothership’s garage is not an extra drain on the ship’s power; it’s making good use of power that is generated anyway.

The environmental benefits of electric power are also attractive to superyacht owners as they try to minimise the carbon footprints associated with large vessels.

There are other options in marine sustainable energy including solar energy-collecting glass and photovoltaic paint. Both these are in their infancy. As energy-capturing technology develops, vessels like Chimera will use their huge areas of glazing to top up their batteries.

Battery and energy storage technology are progressing fast; graphine and aluminium graphite batteries are already offering advanced storage and charging possibilities.

As a petrolhead I love the burble of a couple of V8s under the transom of a classic Riva Aquarama. However the days of fossil fuel powering most vessels available on the market are numbered. Responsible sustainable energy is the future. B