Simon Boyde, well-known to just about everybody in the HKBIA as the first Chairman of the Association and original owner of Storm Force Marine, was in town recently after a business trip into China.
Having left sunny Hong Kong for the perpetual UK drizzle some years ago, Simon now works with ePropulsion (actually, a Hong Kong company) specifically advising on the design and installation of electric power solutions. He is also a member of no less than nine ISO committees drafting and setting standards associated with electric propulsion.
Electric boat propulsion - not so new-fangled.
Electric boats, we heard, have been around for a great deal longer than any of us guessed - 1834 to be precise, and the first outboard motor (1881) was electric, not petrol. Internal combustion engines (ICE) quickly supplanted electric, being safer since replacement of the plates in lead/acid batteries was hazardous to say the least.
More recently, in the 1970s the Duffy Boat Co of California built thousands of electric boats, by which time improved design had rendered batteries a great deal safer. Battery power proved to be especially suitable for tenders - they can be recharged from the mother vessel, and involve no petrol on board.
Coming right up to date, the Candela Co of Sweden (www,candela.com) is successfully selling foil-borne commuter boats that are both fast and cost-effective to run, and require precious little maintenance. Perfect! Recreational boating, where the journey is the destination in itself, is not all about speed. Electric propulsion coupled with good design of the hull, electrical systems, heating, and cooking systems makes for enhanced efficiency with no pollution attached. Think of a long, thin, displacement hull such as a catamaran or a canal boat.
Energy density - how much bang you get for your buck (or kilo).
Electric propulsion units are typically lighter for the same power out put than an ICE, and they run cooler, too. It's the batteries that weigh something, not the electric motors, and a 96v electric motor delivers between 80-90% of its power to the shaft compared with a diesel engine's 10-30%. The higher the voltage of the engine, the higher percentage of its power is 'usable'. A 24v motor delivers 40-60%, and a 48v motor delivers 50-70%. It's that good. Don't be frightened of having a 96v electric motor in your boat; 'arc flash' can occur at 12v just as easily as it can at 250v - it's the current that wreaks the damage, not the voltage.
It's not just lithium batteries that catch fire.
All battery types - modern lead/acid included - have the potential for thermal runaway, so a good battery management system (BMS) is critical. Preferably one with lots of alarms - under-voltage, over-voltage etc - that shut everything down and disconnect the system when otherwise ignored. Battery fires are difficult or impossible to extinguish, so prevention is very much better than any attempted cure. In statistical terms, lithium batteries are safer than lead/acid batteries, and lithium-ion-phosphate (LFP) are the safest of the lot.
Longevity, longevity!
How often have you had to change out a car battery? Too often? Correct. Properly installed, LFP batteries are going to last as long as the boat in which they are installed, assuming your boat has a usage of 50-100 hours per year. And batteries are getting better all the time: before long we can look forward to electrical storage with a 20-year life span.
ePropulsion manufacture and sell electric outboards from 12kW to 40kW, inboard motors from 10kW to 250kW, pod drive motors 1kW-20kW, and batteries 2000kW - 23,000kW.
Anyone looking for more information can contact Simon (simon@epropulsion.uk), or Danny Tao (danny.tao@epropulsion.com) or even check out the website (www.epropulsion.com).
