Cobalt 233 ZET – Zero Emission Technology for Runabouts on Lake Constance

(PresseBox) ( Konstanz, )
Two companies, Brunnert-Grimm AG and zebotec GmbH, have set themselves a challenging goal: to build and sell zero emission runabouts. Increasingly strict emission regulations make it difficult for diesel and petrol motors to obtain certification for Lake Constance operation. The region is therefore ideal as an early market for a new and exciting drive system.

With this in mind, Brunnert-Grimm AG built and tested a runabout in the year 2000 with an electric motor drive. The motor had a capacity of 50kW and the energy was supplied entirely from onboard batteries. Extensive tests demonstrated the feasibility of such a runabout. However they also highlighted requirements for further technical development. The main desire was for an increase in range and a reduction in weight – two significant limitations of the battery system.

The problem of storing electrical energy is not limited to marine applications and following the develpoment in the automotive industry, a decision was made to implement the use of fuel cell technology. Fuel cells are electrochemical devices that convert hydrogen gas into electricity and heat with high efficiency. With water being the only exhaust, this technology is ideally suited to use in boats.

Using a commercially available runabout as a base, Brunnert-Grimm AG, (Gottlieben, Switzerland) and zebotec GmbH (Konstanz, Germany) have created a hybrid drive consisting of electric motors, fuel cells, hydrogen tanks and a battery purely for peak power requirements. System optimisation ensures that the different features of each technology are exploited to a maximum. The boat reaches a top speed of 40 km/h and is operated like any "normal" runabout.

Three hydrogen tanks that can be filled to a pressure of 350 bar, provide sufficient fuel to travel over the entire lake – quietly, smoothly and without any emissions.

The Cobalt 233 runaboat used for this project is manufactured by COBAL BOATS. As 6 time winner of the J.D. Power Award, Cobalt is recognised as a leader in the production of high quality and high performance boats.

The fuel cell boat Cobalt 233ZET, on display for the first time at the INTERBOOT 2007 in Friedrichshafen, is built according to the guidlines of Germanischen Lloyd (GL) and will shortly receive the "GL Certification for Fuel Cell Boats". First deliveries are planned for the European season 2008. Prices for a Cobalt runabout with hybrid drive will be available in November 2007

Information regarding the companies involved:
Brunnert-Grimm AG (
The family operated company Brunnert-Grimm AG has over 100 years of experience in the field of boat construction, customization and sales. The modern Brunnert-Grimm facility with moorage, fueling and storage infrastructure is located directly on the Rhine river linking the two major water masses of Lake Constance. With well established personal contacts to leading US and European boat manufacturers, and representation at all major european boat shows, Brunnert-Grimm offers optimum service to its partners and customers.

Brunnert-Grimm's expertise in the integration of new technology into existing boat platforms was critical to the success of the Cobalt 233 ZET.
The publisher indicated in each case is solely responsible for the press releases above, the event or job offer displayed, and the image and sound material used (see company info when clicking on image/message title or company info right column). As a rule, the publisher is also the author of the press releases and the attached image, sound and information material.
The use of information published here for personal information and editorial processing is generally free of charge. Please clarify any copyright issues with the stated publisher before further use. In the event of publication, please send a specimen copy to