Although propelling a ship with a waterjet can be considered a more modern method than with a conventional propeller, the idea behind it is an old one. In 1631 David Ramsey was awarded an English patent for his idea of propelling a ship with the working principle of modern waterjet propulsion systems. In 1687, Isaac Newton in his Philosophiae naturalis principia mathematica formulated the laws of science that are applicable to Ramsey's idea.