Homegrown propulsion powers Singapore’s high-flying zero-emissions hydrofoil

With some 50 years in the marine propulsion business, Singapore-based Engtek (Pte) Ltd has been researching, developing and marketing electric propulsion solutions globally for more than a decade.

“We’ve been selling electric thrusters for more than 10 years,” says Engtek (Pte) Ltd group executive chairman C W Hon, adding “Well before Singapore looked at electrification for transport.” Mr Hon recalls inviting the Maritime and Port Authority of Singapore (MPA) to tour Engtek (Pte) Ltd’s manufacturing facility six years ago. “They were not aware we were making electric thrusters here in Singapore,” he says.

Now, starting 2030, MPA wants all new harbour craft operating in the Port of Singapore to be fully electric, be able to operate on 100% biodiesel (B100) or be compatible with net-zero fuels such as hydrogen. It wants to add a fleet of zero-emissions vessels over the next 25 years to cut greenhouse gas emissions from harbour craft in half by 2050.

And Engtek’s E-Pod technology will be part of that zero-emissions vessel journey. Its first-of-a-kind E-Pod Velocity hydrofoil thruster is installed in the all-electric, hydrofoil crew transfer vessel (CTV) Hydroglyder, developed by marinEV, a Yinson GreenTech (YGT) business. Hydroglyder  comes equipped with an advanced hydrofoil system that can lower energy consumption by 50-80% compared with non-foiling vessels, according to marinEV, which partnered with Norway’s Lift Ocean AS and Zeabuz in the vessel’s development.

Launched in November, Hydroglyder can reach a top speed of 30 knots, and has a cruising speed of about 25 knots when foiling. The 12-m CTV can comfortably carry 12 passengers and two crew for about 20 nautical miles. Power is supplied by a 252-kWh battery pack.

“Weight was critical in the development of the hydrofoil,” observes Mr Hon. “This required the hydrofoil thruster to be lightweight and manufactured from aluminium — the first of its kind in the world. But we took up the challenge,” he says.

Part of that challenge, Mr Hon notes, was manufacturing the customised engineered E-Pod Velocity hydrofoil thruster from a single block of aluminium, requiring specialised precision machining equipment.

“Building it out of a single block was expensive but it made the unit stronger,” says Mr Hon, noting it had to adhere to stringent DNV class requirements.

Company deputy chief executive Roy Lim says the novel design for the 390-kW thruster took one year to development. Mr Lim says computational fluid dynamics and finite element analysis were used to verify the thruster design, structural strength and performance.

The E-Pod Velocity hydrofoil thruster has three shafts inside the unit, one of which controls the foil on the podded unit and the other two to the contra-propeller, explains Mr Hon. He says the controls were developed by YGT and Engtek handled the integration into its system.

Unlike traditional propellers, E-Pod propulsors do not require a shaftline, gearbox or rudder, lowering the space requirements for the propulsion system. Additionally, they are far more efficient, eliminating power losses via shaftlines, gearboxes or bearings.

Mr Hon and Mr Lim see growth opportunities globally for large electric thrusters in the offshore energy sector and have developed a new generation 200-4,000-kW permanent magnet azimuth thruster.

“Most of the vessels in the future will be electric,” states Mr Hon.