MARINE PROPULSION

'Marine propulsion' is the act of moving an object through the water or across its surface. The most common types are underwater propeller, water jet, paddle wheel and, experimentally, magnetohydrodynamic drive. Sails are also common, and historically represented the most significant form of early propulsion for large watercraft. Poles, paddles, and oars were probably the earliest form of marine propulsion.
Propulsion ,in the dictionary, is discribed as "the act or process of propelling". Which tells us that Marine propulsion must be the way in which a boat, ship, Vessel etc. Propells it self in water. Examples of this would be Propellers, oars sails etc. For more complicated vessels propulsion will also include engine boilers and other such mechanisms