Description
Rigging is an essential part of ship construction and the application of temporary padeye attachments as lifting points is common practice. At present, the standards used by rigging engineers to design the padeye lifting attachments only calculate an in-plane loading capacity at one load angle; approximately 90 degrees from horizontal. This is common for components that are only lifted and moved without rotation. Cost cutting measures, however, have pushed shipyards to build block sections in inverted positions which, through the turning process, typically load padeyes through changes in angle of over 180 degrees. The objective of this study was to perform basic research related to lifting attachment devices used for ship construction to determine if the industry standard calculations for padeye strength are valid through 180 degrees of loading. The emphasis was to use existing resources or, if none are available, develop new methods to perform a series of strength calculations of padeye lifting components. Each calculation would then be validated with a series of full-scale or near-full-scale structural tests to failure. Based on the research and physical testing, a relatively simple computer program has been developed that assesses the ultimate force capacity of a padeye for all angles of possible loading.
