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An oar is a tool used for water propulsion. Oars in general have one flat blade at one end. The user grabs the oar at the other end.

Water Propulsion Oar

An oar is a tool used for water propulsion. Oars in general have one flat blade at one end. The user…

A rudder supported on a skeg or projection from the keel, about one third of its surface being forward and two thirds abaft its vertical axis.

Balance Rudder

A rudder supported on a skeg or projection from the keel, about one third of its surface being forward…

"A propeller acting on the principle of the screw, attached to the exterior end of a shaft protruding through the hull of a vessel at the stern. It consists of a number of spiral metal blades either cast together in one piece or bolted to a hub... D, diagrammatic view of hull of a screw propeller ship, in which k shows position of boilers; l, the engines; f, propeller shaft; e, thrust block; g, propeller." —Whitney, 1889

Screw Propeller Ship, Diagrammatic View of the Hull

"A propeller acting on the principle of the screw, attached to the exterior end of a shaft protruding…

"A propeller acting on the principle of the screw, attached to the exterior end of a shaft protruding through the hull of a vessel at the stern. It consists of a number of spiral metal blades either cast together in one piece or bolted to a hub... C, cross section of blade, on larger scale." -Whitney, 1889

Screw Propeller, Cross Section of a Blade

"A propeller acting on the principle of the screw, attached to the exterior end of a shaft protruding…

"A propeller acting on the principle of the screw, attached to the exterior end of a shaft protruding through the hull of a vessel at the stern. It consists of a number of spiral metal blades either cast together in one piece or bolted to a hub. A. sectional elevation, the section being through shaft and hub, showing method of attaching blades h by bolts i." —Whitney, 1889

Screw Propeller, Sectional Elevation

"A propeller acting on the principle of the screw, attached to the exterior end of a shaft protruding…

"A propeller acting on the principle of the screw, attached to the exterior end of a shaft protruding through the hull of a vessel at the stern. It consists of a number of spiral metal blades either cast together in one piece or bolted to a hub. Side elevation." —Whitney, 1889

Screw Propeller, Side Elevation

"A propeller acting on the principle of the screw, attached to the exterior end of a shaft protruding…

An apparatus which, being fitted to ships and driven by steam, propels them through the water.

Screw-propeller

An apparatus which, being fitted to ships and driven by steam, propels them through the water.