Messrs. Seaward's plan for propelling vessels on canals and other shallow waters consists in the employment of a circular thrusting instrument or spike-wheel to act continuously.

In the annexed cut, a is the spike-wheel, working either outside the boat, or in a compartment within the vessel, but open at bottom. In order to accommodate the wheel to the inequalities of the bed of the canal, it is supported by bearings at the extremity of a swinging frame b; the other end of which is hung to a shaft c, turned by a steam-engine; on this shaft is fixed a pulley or drum d, and a similar pulley or drum e is fixed on the axis of the wheel a, and an endless belt or chain being passed round the wheel, the revolution of the drum d causes the spike-wheel to revolve, and thereby propel the vessel.

Seaward s Spike Wheel 618