Electric boat at sunrise. With Pascal's technology, most of the hull floats above the water.

Double the range with airframe

Remember the word 'AirHull'! Air hulls can solve one of boating's biggest challenges.

The electric boat harbor at Aker brygge is bathed in sunshine on this September morning. The Oslo fjord is silent, interrupted only by the electric ferries, going to and from bustling city centers.

At the quayside, we meet Silje Tolo Haugland and Martin Svalesen from Pascal Technologies. They're going to show us a technology that can be hard to spot. The boat we'll be driving is built in aluminum by Alukin, and it's equipped with a 120 horsepower Evoy engine. On board is a 126 kWh battery pack that weighs 800 kg. But none of this is Pascal Technologies' delivery. Silje explains: "We don't build boats. We deliver a hull technology that any boat builder can use. Boats with Pascal hulls use significantly less energy, because we use air to separate the hull from the water. Hence the word 'air hull'.

The resistance curve

A boat gliding smoothly through the water uses little energy. As the boat speeds up, the resistance from the water increases exponentially with speed. This also increases energy consumption significantly. This sharp increase in resistance at higher speeds is called the resistance curve.

For boats designed to plane (lift out of the water), drag will increase rapidly at first, but then drop again as the boat is lifted over the waves and friction with the water decreases. But it obviously takes a lot of energy to keep a boat up at a sufficient speed so that it can lie flat.

The higher the speed, the higher the energy consumption. Pascal's air hull partially lifts the boat out of the water to reduce drag.

How Pascal technology works

Pascal's solution to the resistance curve is called AirHull - or air hull. The hull is shaped with a regular pointed bow at the front, but underneath it looks more like a catamaran, forming a cavity between the hull sides. When the boat gets up to speed, a fan in the bow starts blowing air into the cavity. The air creates an overpressure that partially lifts the boat out of the water, effectively reducing the boat's drag.

At the back of the boat there is a hinged flap, which ensures that the air pressure stays inside the cavity. This way, only the sides of the boat touch the water while the rest of the hull floats on a 30-centimeter invisible air cushion.

- "Anyone who has played air hockey can understand the principle of the technology we deliver," says Martin Svalesen. He is a software engineer at Pascal. Air hockey is played on a table with a thin air cushion above the playing surface. This air cushion reduces the friction between the puck and the table, allowing the puck to slide quickly and smoothly.

- The low friction from the air cushion in the air hockey table allows the puck to move at high speed. "It's pretty much the same thing that happens with our hulls," explains Martin.

More with less

- "Boats with our technology use significantly less energy than conventional boats," says Silje Tolo Haugland. "For an electric AirHull boat, this means roughly doubling the electric range. If you choose an AirHull boat with conventional fuel, you can increase the range before you need to refuel.

Is it an expensive solution?" we ask.

- For electric propulsion systems, airframes offer the possibility to choose smaller batteries or motor size and thus the cost picture can be evened out," says Tolo Haugland.

Depending on the use of the boat, the actual consumption will influence the cost picture. For boats that are used a lot, there are big savings in energy consumption. In most cases, electricity is much cheaper than fossil fuels.

Sustainable maritime future

Out on the Oslofjord, Martin asks us to notice how quiet the boat is. As the speed increases, it is the sound of the outboard engine and the wind noise that is most noticeable. The fan in the bow is not heard.

Unlike planing boats, Pascal hulls have no planing threshold. It is the air pressure that lifts the boat from the water, not the speed.

The on-board control system automatically controls the fan and hatch, ensuring optimum efficiency. "We design the whole thing to seamlessly adapt to changing conditions, to provide low energy consumption and a comfortable ride," explains Martin.

We want to know if the technology is designed for a specific type of boat.

Silje explains that Pascal develops both air hulls for professional and leisure boats, and air lubrication systems for large boats and ships.

- Our ambition is to deliver technology to all types of ships worldwide. We believe that technology can create a greener maritime future," says Silje Tolo Haugland.