keel claw for clamping the lower ends of the three chains 23 of one staging assembly the claw comprises three steel plates 67 each in a vertical plane forming a triangle in plan view and each having welded to its outer face a depending plate 68 having a downwardly facing slot 69 into which the lower end of one of the chains 23 can be inserted and hooked by a bolt at the lower end of the chain tension in the chain tends to hold it in the upper end of the slot but for safety a drop nose pin 71 is inserted through aligned holes inside pieces of the plate to give positive prevention against release the corners of the triangle of the plates have welded to them lower and upper steel hoops 72 and 73 the lower of which engages a lug 74 welded to the bottom of the hull at 75 and the upper of which is connected to a tensioning chain connection of the chains to the claw is very simple and so is release when tension in the chains is released the coupling for the upper end of a chain shown in fig8 comprises a u shaped shackle 111 and a bolt 112 for closing the mouth of.