Crank 1 rotates about axis D fixed in the boat. When crank 1 rotates, connecting rod 2, having slot b, slides along pin 3 fixed in the boat. At this, point A of connecting rod 2 describes connecting-rod curve a as a result of which arms 4 holding the oars and body 5 of the oarsman, oscillating about axis C, are imparted the required motions.
$1455$LG,FD$