With a top speed of 25km/h and capable of travelling 120 metres below the surface of the water, the Delfjet water scooter was developed to give its users the manoeuvrability and speed of a dolphin.
Developed in Germany by Jurgen Grimmeisen, the initial prototype was powered by a petrol engine, and later prototypes progressed through more hydrodynamically styled versions.
The method of propulsion was then changed to a silent, Newtor Brushless 42v electric motor driving an impellor for the water jet.
Power for the motor initially came from conventional nickel-cadmium batteries, but their low endurance (25A/h capacity) and high weight (35kg) was a problem, particularly as the weight of the Delfjet without batteries was just 16kg.
This was when the designers plumped for the High Energy lithium-ion cells from Saft. These batteries, originally designed for use on electric vehicles, were found to be far superior to the nickel-cadmium batteries used in the prototype, offering nearly twice the capacity at around one third of the weight.
It is believed that the new vehicle will have great value in lifesaving operations in beaches.