The shell shape propeller is a propeller of high thrust high efficiency energy saving.The high efficiency comes from the fact that is blades have two-way concave paraboloid which differs from the common propeller helicoids. The biggest performance characteristic is that the thrust increases about 20% with promising sailing speed. Therefore it is especially suitable for trawlers and tugboat which are not equiped with nozzle. This performance of shell-shape propeller has been confirmed by tests and used in many trawlers.