SES-X air-cushioned hull taking off with electric ferries, high speed leisure boats

Using technology developed over the past two decades, the SES-X air-cushioned hull pumps air between the boat and water surface to significantly reduce water resistance, making the technology extremely attractive for electric boats.

The company that developed the Surface Effect Ship solution – Norway’s SES-X Marine Technologies –  says its extensive research, development and on-water testing shows the system reduces the energy consumption of high-speed vessels by up to 50% compared to conventional hulls.

The SES-X core technology is based on the work of an earlier R&D company, Effect Ship International (ESI), which was acquired in 2019. The concept has been verified with two full-scale pilot vessels, including the 20 metre, 70+ passenger BB Green Ferry. With a new name, capital and new team, the unique technology is now ready to be commercialized.

Air-cushioned hull has been proven in the BB Green Ferry, shown at speed
The 20 metre BB Green Ferry, equipped with the SES-X air cushion system

The technology is generating big excitement and SAS-X has announced four significant pieces of news in the past few weeks:

  • Their project in the Fremtidens Hurtigbåt (speedboat of the future) competition has been approved for the finals stage by the four Norwegian city councils who requested submissions for high speed, long range zero emission ferries
  • They are working with Moen Marin on a new 40 nM range electric personnel transport boat for the aquaculture industry
  • They have established a new electric leisure boat company in conjunction with Frydenbø Marine, one of the largest boat producers in the Nordics, and
  • They have opened a pre-Series A funding round building on their 2022 successes with a $3M seed round, $1M grant from Innovation Norway to build an 8m electric boat prototype, and $1M from the Norwegian government to design a fully electric fast ferry.

The company is tight-lipped about the specifics of their technology, but conceptually it can be thought of as a sort of cross between a hydrofoiling boat and a hovercraft. The goal in all cases is to reduce the friction between a boat and the water by raising the boat’s hull above the water surface. air-cushioned hull cutaway diagram showing batteries, motors and fan

That water resistance is the main challenge to overcome when creating electric boats that combine high speed with long range. It just takes so much energy to overcome the friction that it is difficult to have enough left over in a practical battery to achieve the kind of range a fossil fuel boat provides.

Hydrofoiling boats lifts the hull through underwater ‘wings’ and a hovercraft or boat with SES-X  does it by creating a cushion of air. The boat’s energy consumption goes down, range goes up, passengers have a more comfortable ride because there is no wave interaction, and the wake and water turbulence from the boat are reduced to almost zero. When running at speed, the SES-X prototype for a 27 metre ferry has only 0.8 meters of the hull in the water.

Sensors and ride control system adjust air cushion

The ‘secret sauce’ of the SES-X system is the hull itself, which, aside from generating the air cushion, is a combination of a catamaran and monohull. That design combines the stability and deck space of a catamaran with the hull volume of a monohull.

The volume is important because it provides space for the fans that create the air cushion as well as the batteries necessary for the fans and electric propulsion motors. Sensors collect data as the boat is in motion to adjust the air output from the fan.

That hull has been designed as a platform that can have any topside installed, so it can be applied to the kinds of boats in the announcements above: leisure boats, water taxis, work boats and passenger ferries.

four hulls with different topsides: workboat, speedboat, watertaxi, ferry


SES-X air-cushioned hull in high speed ferries competition

In October 2019 councils along the coast of Norway requested proposals for high speed zero emission passenger vessels to replace the existing six high speed fossil fuel ferries that together contribute carbon emissions equal to about 1,000 buses.

Volvo Penta buys stake in Norwegian battery company 

They have now decided on four finalists, with the SAS-X technology included in the submission by ship design company ESNA, whose founders, Trygve Espeland and Nere Skomedal, have a combined total of over 50 years of experience with hovercraft…but always with diesel-electric and hybrid propulsion.

This is the first all battery design. It will be propelled by Volvo Penta pod units and driven by Danfoss electric motors, – an example of the kind of project the two companies were referring to when they announced a formal partnership last year to boost marine electrification.. The batteries have been developed by Norwegian firm ZEM, in which Volvo Penta bought a 60 per cent stake in June 2021.

Electric leisure boat venture with major Nordic manufacturer

In starting a new electric boat company together with Frydenbø Marine, SES-X will be working with one of the leaders in the Nordic recreational boating market. They manufacture the high profile Nordkapp, Sting, and Airborne boats, and distribute Zodiac boats within the region. “We could not have found a better partner in Frydenbø”, said Glen Ole Rødland, Chairman of the Board of SES-X. Combining SES-X’ technology expertise and Frydenbø’s market knowledge and market position, creates the best starting point for successful growth.”

SES-X technology being tested in Norwegian winter
Winter testing of SES-X electric prototype

World’s largest aquaculture vessel supplier

In the workboat market, SES-X is teaming up with another leader.  Moen Marin is the world’s largest supplier of work vessels to the aquaculture industry and has delivered more than 250 boats to fisheries and associated companies in the past 10 years.

One of the most important elements of the industry is transporting personnel to and from the remote aquaculture fish farms. Range is obviously important, but so is speed. The other big factor is the cost of the transportation both in initial capital expense and ongoing fuel and maintenance charges.

Electric boats have  a distinct advantage in the long term cost department, and the new NabWork 1240 electric personnel transport vessel with SES-X technology brings the range and speed to the game.

The NabWork 1240 is designed to carry 6–10 passengers and a range of 40 nautical miles makes it capable of visiting a couple of off shore facilities to drop off or pick up people “Propulsion technology with batteries and electric motors is well proven, says Lars Ivar Elvertrø, Sales Director of Moen Marin. “With this range and a speed of 20 knots, the NabWork 1240 is almost a world record.” The aim is to get the first boat operating in the autumn of 2023.

Drawing of the the NabWork 1240 electric aquaculture workboat
Drawing of the the NabWork 1240 electric aquaculture workboat


On the financial side of things, SES-X has been backed by existing Venture Capital investors Momentum Partners, CoFounder, and Link Capital. The $1M in grant funding from Innovation Norway and $1M from the Norwegian government were instrumental in developing the prototypes and ferry design, and the company is now poised for bigger things.

The company has opened a pre-Series A funding round with the proceeds to be used toward delivering these first projects, expanding the production and sales team and pursuing further R&D.

New funding round announced for big future

Chief Executive Officer Carl Rehn said: “In the past years, we have been working hard to get into a prime position in this new market space of high speed, long-range electric boats. So I am very eager to welcome new investors on board to accelerate our commercialization projects. There is large potential to piggyback on the massive momentum from the automotive industry with batteries and chargers, particularly, for smaller crafts such as leisure boats and ferries.”

Staff of SES-X Marine Technologies on deck of prototype ferryRehn, who holds a Ph.D. in marine engineering, joined the company in 2020, having previously worked at Boston Consulting Group as a management consultant for energy and shipping companies. He joined Chief Technical Officer Per Sondre Sodeland, who led the development and commissioning of the 8-meter prototype. The company now has 15 employees.

Chairman of the Board is Glen Ole Rødland, renowned within the energy and shipping industries with more than 25 years of experience. He also acts as Chairman of the board for ABL-Group and Prosafe and was previously a senior partner at HitecVision and Ferncliff.

Commenting on the technology, Rødland said, “The introduction of new technology is demanding in a relatively conservative industry, but leisure boats are leading the way. We anticipate that small vessels will be the first to convert to electric propulsion and more efficient hull solutions. SES-X is developing innovative technology that we are positioning to become a key contributor to the future of electric vessels.”

Arve Fresvik, Managing Partner at Momentum Partners, said “This is a company with a dedicated and competent team, an asset light-and scalable business model, and we are excited to see the company now commercialize in several segments with strong partners.”

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