Overboarding and lowering large loads offshore using guide acting in compression

摘要

A method for lifting, overboarding and lowering a load 20, for example an oil platform template, from the deck 12 of a vessel (10, Figure 1) using a vessel-mounted crane 14 comprises placing at least one guide arm 30 acting in compression between load 20 and crane 14, and lowering guide arm 30 to restrain horizontal movement of load 20 as load 20 is lowered. Guide arm 30 may be placed beside load 20 and attached to a mount on a pedestal 18 of crane 14 to rotate about a slewing axis of crane 14. Guide arm 30 is preferably in position before the load is lifted to restrain horizontal motion of load 20 as the load is lifted and moved outboard. Preferably, guide arm 30 can extend telescopically as the load is lowered.