| 摘要 |
An improvement to oars which will provide additional power per stroke for the same effort from the oarsman. An oar for a watercraft, the oar comprising a blade and a shaft, the blade having a front side and a back side, and the shaft having a longitudinal axis; wherein the blade includes a plurality of slit shaped openings oriented substantially perpendicularly to the longitudinal axis of the shaft and passing from the front side to the back side is disclosed. Also disclosed is an oar for a watercraft, the oar comprising a blade and a shaft, the blade having a front side and a back side, and the shaft having a longitudinal axis; wherein the blade includes a plurality of openings passing from the front side to the back side; and wherein the smallest lateral dimension of each opening is 5 mm or less. Further disclosed is a method of increasing the efficiency of an oar comprising a blade by providing a plurality of openings passing from a front side of the blade to the back side of the blade. The openings may influence the flow around the blade so that the blade is more efficient, and thus may produce more useful work in moving a boat than a solid blade with no openings. |
