GB1411490A - Method and apparatus for the transfer of persons and articles in marine situations - Google Patents

Abstract

1411490 Transferring loading to boats; stress limiting R A BEGAULT 21 Nov 1973 [22 Nov 1972] 53942/73 Headings B8E and B8B Transfer apparatus for lowering a cage 12 with its load from a fixed platform, by a crane cable 17 to a boat 11 comprises a piston cylinder device 21 in a closed pneumatic circuit inserted between the cage 12 and the crane cable 17 a deadline 22 being attached below the cage. From the rest platform position, Fig. 2, after loading the cage 12 a valve 14, Fig. 5, is opened thus venting the system and allowing the crane cable 17 to extend the piston rod 19. Closure of the valve 14 and locking of the cable 17 allows on re-opening of the valve a pressure source through connector 13 to pressurize the reservoirs 26 and cylinder 21 thus retracting the rod 19 to raise the cage 12 from the platform. The crane then positions the cage at ¢-wave height above the boat and the deadline 22 is connected to a boat winch 25 which draws the cage on to the boat deck against the cushioning effect of increased pressure in the cylinder 21 and holds it there for unloading. If a larger return load is loaded the system may require greater pressurization by connecting through the connectors 13 to a source of pressure in the boat. To prevent a dangerous sudden rise of the cage if the deadline restraining force suddenly fails a poppet valve is inserted in circuit to the vents of the lower end of the cylinder 21 which valve on failure closes to restrict the vents and thus the raising speed of the cylinder by spring pressure normally overcome by the pull of the deadline 22.