The engineer Jean Antonio Aldecoa, also known for his ornithopter model, files a patent for a curious articulated marine gear device that propels itself with no other energy input than that of the sea on which they sail.
Some time later, the device is put in place on a prototype ship: the Hydrotrén.
The unit formed an articulated ship hull which, wanting to adapt at any time to the undulating shape of the sea surface, set the water compressor pumps in motion and a turbine that transmitted its force to the propeller of the ship.
The boat was also equipped with an auxiliary gas engine, to have a propulsion at the entrances and exits of the ports or in case of excessively calm sea.
The engineer had also experimented with a similar system installed on the shore to try to recover waves energy.
