The Stralsund-based shipbuilding company Ampereship GmbH is delighted with the result of a spectacular ship test. On 10 July 2025, the electric solar passenger ship ‘Insel Mainau’, designed and built by Ampereship, completed a sensational range test on Lake Constance. During an impressive 19-hour continuous journey, the all-electric catamaran covered exactly 211.3 kilometres on the lake – with a remaining battery capacity of 20 percent. The ship was back in regular operation the very next day.

The 300-kilometres mark would have been possible in a test designed exclusively for range. Another record journey is already planned for next year in order to be able to implement the data obtained on the currents in Lake Constance and the maximum energy efficiency of the ship. According to the shipping company Bodensee-Schiffsbetriebe GmbH (BSB), based in Constance, this will be the longest emission-free journey on the water with an all-electric passenger ship to date. ‘With this test, we wanted to prove how efficient the electric-solar drive of our ship is,’ emphasised BSB Managing Director Christoph Witte, ‘and at the same time motivate other shipping companies to also use fully electric drive systems on their ships.’

The BSB shipping company commissioned Ampereship, a sister company of Ostseestaal GmbH & Co. KG, with the design and construction of the 30-metres-long and eight-metres-wide all-electric catamaran in 2021. ‘We are delighted that this extraordinary test has impressively confirmed the propulsion technology designed by Ampereship and the ship’s efficient energy management,’ commented Thomas Kühmstedt, Managing Director of Ampereship GmbH, on the record-breaking trip on Lake Constance. The energy concept of the ‘Insel Mainau’ passenger ship has set new standards in shipbuilding. The Stralsund specialists developed their own control and optimisation software and integrated it into the system. In addition, an innovative magnetic mooring system and, for the first time, bifacial (two-sided) solar modules, a development of the ISC Konstanz e.V. (International Solar Energy Research Centre), were used, which can generate renewable energy on their front and rear sides.

After completion on site at Lake Constance, the new electric catamaran “Insel
Mainau” was launched in Friedrichshafen in mid-2022
Photo: BSB/Kaestle

Since the middle of the last decade, Ampereship has developed into one of Europe’s leading manufacturers of electric solar-powered ships for professional inland shipping. The Stralsund-based company’s expertise in sustainable and emission-free shipping recently convinced Hafenprojektgesellschaft Helgoland mbH to commission Ostseestaal and Ampereship with the development and construction of a fully electric, ocean-going ferry at the start of 2025. The so-called dune ferry will connect the German North Sea island of Heligoland with the neighbouring island of Düne.

The lightweight aluminium hull of the dune ferry has now been completed. It has been optimised in terms of flow technology and thus ensures high energy efficiency and a long service life. In addition, the hull can be 100 percent recycled, which underlines the Strelasund shipbuilders’ commitment to implementing sustainability and environmental protection requirements throughout the entire life cycle of a ship – from the first design sketch to scrapping. Meanwhile, Ostseestaal/Ampereship is realising its 23rd shipbuilding project with the Heligoland ferry.
Source: Ampereship GmbH