Sealegs, the New Zealand- based manufacturer of amphibious boats has finally made the move over to electric propulsion for its land driving wheels.

Formerly Sealegs boats were powered on land by a Honda 10hp aircooled engine driving a hydraulic pump to operate hydraulic wheel motors. This had limitations, particularly on the earlier models with the aircooled motor, which due to it being a land equipment derived engine, having to be imprisoned in a deck console with limited air flow limiting its operating window on land due to the cooling challenges.

For its dry land propulsion system the new Sealegs Electric E4 has ditched the lawnmower engine and hydraulics for the more obviously suitable lithium battery and brushless electric hub motor technology.  It has been developed based on the patented Sealegs amphibious system together with over 17 years of Sealegs proprietary amphibious system knowledge, marinisation techniques and experience.

The boat remains powered on water by a range of off-the-shelf outboard motors.

The high density 7kWh lithium battery delivers up to 20 return launch and retrieve journeys on land between charges. Charging is via a built-in mains charger as well as by regenerative braking on land and on-water from the outboard. Mechanical brakes are integrated into the hub motors.

Sealegs Founder and Chief Technology Officer Maurice Bryham said “The release of the Sealegs Electric E4 takes Sealegs global leadership position in amphibious technology to the next level. It is the result of numerous developmental electric prototypes and our ongoing multimillion-dollar investment in amphibious research and development”.

“With Sealegs Electric E4 we have made our amphibious system 33% faster, 60% quieter and 50% more powerful.”

The Sealegs Electric E4 incorporates a Sealegs Amphibious Traction and Control System called AmpTracs. AmpTracs controls the entire amphibious operation and the user interface is through a single unified display. As well as advanced traction control and lithium battery management, the Sealegs AmpTracs controls digital switching of lights and other onboard electrical functions.

The Sealegs Electric E4 model has been developed by Sealegs in New Zealand working in partnership with specialist companies and engineers in Germany, UK, Netherlands and Italy.

While this first electric version is aimed at the high end leisure market, subsequently the technology will filter down to improve the company's commercial and SAR vessels. Sealegs also makes its technology available to other boatbuilders, so it is possible that this improved electric propulsion will become available on a range of other craft in due course.

By Jake Frith