OAR Russian patent published in 2009 - IPC B63H16/04 

FIELD: transport.

SUBSTANCE: oar comprises double-bank part, blade part and handle. Oar blade is formed along cylindrical parabola in compliance with y²=2PX, where 3≥P≥1, with smooth blade end bend for 30° to 45°. Blade profile is formed according to form of two parabolas constructed from origin of Cartesian axles by the formulae Y₁=K₁X^1/2, Y₂=K₂X^1/2, where K₁<K₂, 2≥K₁≥1, 3≥K₂≥1, while that with bent ends feature start with radius R₀ apex with radius R₁. Note here that R₁≥R₀. Oar handle is coupled, via shackle, with two extension springs and, via turnbuckle, with boat hull. Conical or cylindrical spring can also be coupled with oar handle, the spring being rigidly fixed in boat rowlock.

EFFECT: higher efficiency.

3 dwg