It’s a good time to consider an electric/hybrid retrofit
For captains and owners considering vessel repowering options, electric and hybrid conversion is a highly viable solution, particularly when considering the current status of electric power systems technologies, rapid improvements in battery safety and capacity, and advances in solar panel technology. Power systems that have been developed for automobiles are readily transferable for vessel propulsion — in fact, electric ferries and workboats are already commonplace in European harbors and commercial operations.
While not every vessel is suitable for electric/hybrid retrofits — such as, say, 50-foot outboards — custom electric and hybrid retrofits for private yachts are now available with ever-evolving capabilities. Displacement and semi-displacement hulls are the best candidates. With the assistance of a naval architect to determine how best to balance the trim with the vessel design, captains and owners have some flexibility and choice for the layout of equipment.
These refits are best undertaken from a whole-vessel redesign rather than a piecemeal approach. Requirements for batteries, electric motors, control system, electrical converters, cooling, charging, etc., must be integrated within certain existing hull constraints. However, with input from the owner and captain, the system can be designed to exactly suit the owner’s requirements.
Modern batteries for boats are powerful, smaller, cheaper and safer than previous generations, and they are readily available from many international manufacturers, as well as increasingly in the U.S. They are quite different from the batteries in portable devices, which are the source of most catastrophic battery fires reported in the news. Many fires that have been widely reported as propulsion battery fires actually occurred in cellphones, underwater strobe lights and underwater scooters.
Modern electronic inverters can run a yacht’s hotel loads, including the galley equipment and air conditioning, from the same lithium batteries that are used for propulsion. In many cases, pumps, blowers and other mechanical devices can be powered directly from the batteries by using special electronics called variable frequency drives, resulting in even greater efficiencies.
Solar panels — now with lower costs and improved reliability due to increasing production — can be incorporated into upper surfaces, such as shade umbrellas and the cabin roof, to help recharge the batteries while at anchor and reduce hours of generator noise.
The return on investment is especially high in terms of owner and guest expectations: a luxurious yachting excursion offering escape from the noise and stress of their daily lives. It’s entirely possible to quietly depart a lovely harbor in the morning while guests enjoy a breakfast untainted by diesel fumes, or to arrive at an anchorage late at night without the rumble of a diesel engine awaking the owner. Most owners and guests today are already tuned into the popularity and availability of electric vehicles, as well as the dual benefits of quiet operation and reduced reliance on fossil fuels. Just imagine how luxurious air conditioning is without the accompanying drone of engine noise and fumes!
Dan Hanes is an electrical engineer, naval architect, and owner of Sea3 Systems, a company that provides high-technology design services for the marine industry.