Abstract
A Semisubmersible-type bucket ladder dredge is a possible candidate to satisfy the need of PT Timah (Indonesia tin mining company) to exploit tin deposits in water depths of 50 m and deeper. The existing vessel used by PT Timah, barge- type bucket ladder dredge, is only capable of operating in depths shallower than 30 m. In order to evaluate the dredging capability in 50 m water depth, a dynamic analysis of both semisubmersible-type and barge-type bucket ladder dredges was conducted. The proposed vessel, a semisubmersible-type, was designed by modifying an existing semisubmersible platform used in the oil and gas industry, while the barge-type used is from a conventional bucket ladder dredge. Hydrodynamic coefficients and response amplitude operators (RAOS) of both vessels were computed by using WAMIT (Wave Analysis MIT) software and AutoCAD RI") was used for design purposes. The response spectra of the vessels were obtained in head, quarter, and beam seas of sea state 4. The effect of mooring stiffness is also presented. Besides modeling the system with low stiffness, such as a catenary mooring, the dynamic analysis was also conducted for the free-floating condition. Finally, the motion performance between the two vessels was compared for various sea conditions, and it is shown that the semisubmersible-type bucket ladder dredge performs better with smaller responses in the selected sea conditions expected in deeper water depths (> 50 M).
Arcandra (1998). Dynamic analysis of a semisubmersible-type bucket-ladder dredge. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1998 -THESIS -A724.