Instability

Nor is this any very easy matter; for in his rear is the immense projecting steering oar hitting him now and then in the small of his back, the after-oar reciprocating by rapping his knees in front. He is thus completely wedged before and behind, and can only expand himself sideways by settling down on his stretched legs; but a sudden, violent pitch of the boat will often go far to topple him, because length of foundation is nothing without corresponding breadth. Merely make a spread angle of two poles, and you cannot stand them up.