The production-ready solar-powered Solarwave 64 powercat solves the limited-range conundrum of true electric boats

Keep it quiet

Initial sea trials (as yet unverified by our own testers) show that at 6 knots, the two 60kW electric engines consume just 12kW. Increasing the speed to 7 knots pushes this demand up to 19kW, while 8 knots requires 30kW. The maximum speed of this model is limited to 10 knots at 70kW in order to maximise efficiency at its 7-8-knot cruising speed.

These higher speeds do involve drawing additional power from the battery bank but with 50kWh of lithium batteries as standard and a further 50kWh as a €40,000 option, there should be no issue with maintaining these higher speeds for several hours on end. Even with no sun at all, a fully charged bank of batteries should be good for a range of 50-100nm depending on speed.

The saving grace is that as soon as you slow down or drop the hook for lunch, the batteries start to recharge themselves. This, and the safety net of a conventional diesel generator or ‘range extender’ as Silent Yachts like to call it – in this case a 25kW Fisher Panda – finally puts paid to the dreaded range anxiety, which owners of electric cars and boats suffer from.

Solarwave 64

One of three double cabins on the first boat. A four-cabin layout is also possible

The proof of this was demonstrated by the original 2009 Solarwave 46 prototype, which underwent a rigorous five-year sea trial around Europe, clocking up over 2,500 hours on the electric motors but a mere 50 hours on the generator, most of which were added to prevent it seizing up from lack of use.

The inclusion of a 10kVA inverter and an all-electric galley as well as air con, heating and a watermaker as standard means that you should be able to cruise for weeks at a time without having to visit a marina.

Solarwave 64

The luxurious saloon shows no compromises are necessary on a solar-powered vessel

For those who insist on a higher speed capability, there is also an option to fit larger electric and diesel engines delivering 20 knots or more. So far, just the one 64 has been completed with a second one in build. Unfortunately, limited capacity at the third-party shipyard contracted to build it in Turkey means the next available delivery slot for the 64 is in 2019.

Solarwave 64

Masses of living space on the 31ft 2in (9.5m) main deck

That’s why the Swiss parent company Silent Yachts is now focusing its attention on two new models it’s having built in China – a 54ft cruiser with prices starting from €1.13 million ex VAT due out this October, and a 70ft cruiser pencilled for launch in spring 2018 at an undisclosed price.

The Silent 54 is being offered with a variety of electric power options from twin 25-135kW motors each side and Volvo or Mercruiser diesel power from 75hp-220hp. The Silent 70 will get more powerful 50-135kW electric motors and up to 2 x 400hp diesel motors.

With five orders already taken for the new Silent 54 and one for the new 70, it looks like this could be the start of a quiet revolution.

Contact www.silent-yachts.com

Technical details

Length 63ft 9in (19.43m)
Beam 31ft 2in (9.5m)
Draft 3ft 7in (1.1m)
Motors Twin 20kW electric (60kW option)
Top speed 10 knots (electric only)
Displacement 25 tonnes (light)
Water capacity 1,000 litres
Fuel capacity 1,000 litres
RCD category A for 12 people
Price from €1.96 million ex VAT

  1. 1. Introduction
  2. 2. Keep it quiet
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