Abstract: A remotely controlled cyclic grapnel hook apparatus includes a cylinder wh has a top and a bottom, the cylinder having a central bore axially therethrough and a counterbore in its top portion. A piston is slidably mounted in the cylinder counterbore, and a piston rod connected to the piston is slidably mounted in the cylinder bore therebelow. The piston and piston rod are biased downwardly by a spring which may be located in the cylinder counterbore. The cylinder has a passageway to the bottom of the counterbore so that fluid pressure can be applied or released therein for moving the piston and piston rod up or down in the cylinder against the force of the spring. At least one hook is pivoted to the bottom of the cylinder so as to extend outwardly therefrom.

Abstract: A motion compensating tank which includes a bottom tank portion which is able of holding liquid and a top portion which has a flotation collar and a flexible collar. The flotation collar is buoyant in the liquid so as to float substantially level thereon, and the flexible collar sealably joins the flotation collar to the bottom tank portion. With this arrangement liquid which sloshes in the tank can be retained without any substantial spilling over the top of the tank.