An experimental analysis of the dynamics of a submerged tethered cradle in a seaway
Cohen, Jay Martin
MetadataShow full item record
Submerged recovery of small submersibles by means of surface tethered platforms offers the possibility of operations in sea states higher than is now possible using surface recovery means. The Woods Hole Oceanographic Institution's submersible support catamaran LULU has such a tethered system. The system consisting of cradle, chains, and hoist is designed to recover DSRV ALVIN at a depth of 100 feet, and then lift the submersible rapidly through the air-sea interface. Scientific commitments as well as possible damage to the cradle and/or ALVIN, and danger to personnel have prevented full scale recovery experiments. A 1/40 scale model of the catamaran, chain and cradle was constructed to investigate cradle heave and pitch response in regular sinusoidal waves. Model tests were conducted at the Massachusetts Institute of Technology Tow Tank Facility and data was recorded electronically and photographically. Test runs were made at various ship speeds, cradle depths, wave heights, wave lengths, and cradle suspension modifications. Results indicate that for the existing system, cradle pitch and heave is only slightly attenuated over catamaran response at speeds less then 3 knots (full scale). By decreasing the number of cradle suspension points, and varying hoist resiliency and cradle added mass characteristics, cradle motion can be substantially reduced over catamaran motion.
Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution and Master of Science in Naval Architecture and Marine Engineering at the Massachusetts Institute of Technology May, 1972
Suggested CitationTechnical ReportThesis: Cohen, Jay Martin, "An experimental analysis of the dynamics of a submerged tethered cradle in a seaway", 1972-06, DOI:10.1575/1912/1224, https://hdl.handle.net/1912/1224
Showing items related by title, author, creator and subject.
Krishfield, Richard A.; Toole, John M.; Proshutinsky, Andrey; Timmermans, Mary-Louise (American Meteorological Society, 2008-11)An automated, easily deployed Ice-Tethered Profiler (ITP) instrument system, developed for deployment on perennial sea ice in the polar oceans to measure changes in upper ocean water properties in all seasons, is described, ...
Timmermans, Mary-Louise; Toole, John M.; Proshutinsky, Andrey; Krishfield, Richard A.; Plueddemann, Albert J. (American Meteorological Society, 2008-01)Five ice-tethered profilers (ITPs), deployed between 2004 and 2006, have provided detailed potential temperature θ and salinity S profiles from 21 anticyclonic eddy encounters in the central Canada Basin of the Arctic ...
Bowen, Martin F. (Woods Hole Oceanographic Institution, 2001-06)Neutral tethers for unmanned underwater vehicles may contain a bundle of single-mode, optical fibers that are protected inside flexible stainless steel tubing. To date the author knows of no commercially available systems ...