One example is the windmill ship which captures wind energy with a rotor that drives a conventional propeller.
Unlike the rest of the Trafalgar-class boats that followed, she was not launched with a pump jet propulsion system, but with a conventional 7-bladed propeller.
Electrical power then drives high-torque density induction motors which turn two conventional (non-azimuthing) propellers.
The second prototype was fitted with conventional propellers and flown on 5 April 1947, after Hughes had recuperated from his injuries.
Aircraft with conventional propellers, therefore, do not usually fly faster than Mach 0.6.
Instead of a conventional propeller Alrosa uses a pump jet propulsion system.
It also serves to counter the asymmetrical torque effect of a conventional propeller (see P-factor).
Then the giant props would function as conventional propellers, though very large ones.
Such vertical windmills, shaped like eggbeaters, have an advantage over the conventional propellers mounted on posts because they can "accept" wind from any direction.
This enables vessels to operate in shallow waters and offer higher speeds and better maneuverability than conventional propellers.