Abstract: A holddown device has a clamp arm pivoted on a base. The clamp arm has a hook end extending outwardly from the pivot. A tail extends outwardly from the pivot at an acute angle to the hook end. A cam is pivoted on the base. The cam has a camming periphery engaging the tail. The cam is rotatable in one direction to a locking position and in the opposite direction to a release position. The cam, upon rotation to the locking position, swings the clamp arm from a retracted position to a clamping position. A link pivotally interconnects the cam and the tail of the clamp arm.