Abstract: A device for locking the vertical position of a leg relative to an off-shore work platform having a vertical rack with angular teeth and a lock body with mating angular teeth. The lock body is positioned between a pair of upper and lower wedge members adapted to slidably engage a horizontal face on one side and an inclined face on the other side. The inclined faces of the upper and lower blocks are in opposed directions parallel to the pressure faces of the teeth of the rack and block body. The wedge blocks are adapted to be displaced horizontally in coordination so that when moved simultaneously, a horizontal displacement of the lock body occurs, and when one is moved without the other, an angular displacement of the lock body parallel to the pressure surface of the meshing teeth of the rack is obtained.

Abstract: An oil fence arrangement for effectively preventing oil spills from spreading or diffusing over the surface of the sea. The arrangement is of a double wall construction and can fold into a small space.