Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2004. / Includes bibliographical references (p. 109-110). / Hydrofoil ships cruise at large speeds and are often expected to operate in rough weather conditions. The motion of these ships due to their encounter with ambient waves can become uncomfortable or even dangerous without the use of some form of motion control. The objective of this thesis is to study the active motion control of high-speed hydrofoil vessels. This work is composed of two parts, reflecting the two disciplines applied: hydrodynamics and optimal control theory. In the first part, a two-dimensional computer code is developed for the calculation of forces and the integration of the equations of motion for fully submerged lifting bodies operating near a free surface. A Rankine source boundary element (panel) method is used assuming potential flow around the body. As a result, the motions of a hydrofoil vessel operating at high speed in ambient waves can be estimated in the time domain. In the second part, the application of optimal control theory to motion control of hydrofoil ships is investigated. The code developed in the first part of this work is used as a simulation tool for the assessment of control laws designed using state-space linear-quadratic methods. / (cont.) It is found that a linear-quadratic optimal controller can attenuate the motion response of the vessel advancing in monochromatic or ocean waves, with proper adjustment of the cost matrices that enter the quadratic performance criterion used. Accurate dynamic modeling is crucial in the design of control laws for any system. Vessels that operate on or near the free surface experience hydrodynamic memory effects due to their own motion. Casting the seakeeping equations of motion into a linear, time-invariant state-space model suitable for the design of optimal control laws is challenging since there is no straightforward way of including these memory effects in the model. In this work, the seakeeping equations of motion are cast in a linear state-space form which does not include memory effects, and the motion control simulation results show that this model is satisfactory for the design of hydrofoil vessel control laws. / by Iason Chatzakis. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994. / Includes bibliographical references (p. 182-188). / by Koay, Peng Yen. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1989. / Includes bibliographical references (leaves 229-230). / by Anastasios Haralampos Aslidis. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997. / Includes bibliographical references (p. 93-96). / by Michael Oliver Jastram. / M.S.

Thesis (Nav.E. and S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2000. / Includes bibliographical references (leaves 76-78). / by Nikolaos Bekiaris. / Nav.E.and S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1991. / Includes bibliographical references (leaves 164-167). / by Hyun Yup Lee. / Ph.D.

Thesis (S.M. in Ocean Systems Management)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2003. / Includes bibliographical references (p. 96-102). / by Parker E. Larson. / S.M.in Ocean Systems Management

Thesis (S.M. and Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2005. / Includes bibliographical references (p. 91-93). / The IJ.S. Navy's new system for rescuing stranded submariners, the Submarine Rescue Diving and Recompression System (SRDRS), utilizes a tethered, remotely operated Pressurized Rescue Module (PRM) deployed and controlled from a Vessel of Opportunity (VOO). The PRM is capable of docking with the disabled submarine at pressure and rescuing up to 16 personnel per sortie. The PRM is launched and recovered using a deck mounted A-frame crane called the Launch and Recovery System (LARS). Upon recovery, the PRM docks with the Submarine Decompression System (SDS) to allow transfer and decompression of personnel. The PRM, LARS, SDS, and associated generators and auxiliaries all compose the Submarine Rescue System (SRS). The SRS, approximately 183 tons, is installed aboard the VOO. The SRS was nominally designed for operation on the U.S. Navy's Auxiliary Fleet Tug, T-ATF, but is actually intended to be a fly-away system, capable of being installed on any available VOO near the disabled submarine. The VOO may be any Offshore Supply Vessel (OSV), Anchor Handling Tug, or offshore barge that has the capacity to handle the SRS and is available in the area of a disabled submarine. / (cont.) Since the SRS must be rapidly deployed, potential VOOs must be quickly identified and evaluated for structural, stability and seakeeping suitability with respect to the requirements for the SRS. This thesis describes the theoretical background and development of a procedure intended to aid in the analysis and evaluation of potential VOOs for stability and seakeeping suitability. This procedure utilizes limited information about the potential VOO such as length, beam, draft, depth, deck strength, dead weight tonnage, etc. as inputs for rapidly modeling hull geometry. The developed hull geometry is combined with an empirically derived weight distribution which serve as the input for stability analysis for several different load cases and the seakeeping analysis. Theoretical and empirical analyses are used to justify the requisite assumptions and estimates used in developing the VOO stability and seakeeping models. The efficacy of this VOO evaluation process is demonstrated by both a comparison to known stability and seakeeping analyses for the T-ATF, and with a sensitivity analysis of assumed variables. / (cont.) With this process, the U.S. Navy will be able to rapidly analyze and evaluate the stability and seakeeping characteristics of potential Vessels of Opportunity and judge their suitability to carry and deploy the Submarine Rescue System. / by Robert Andrew Gold. / S.M.and Nav.E.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997. / Includes bibliographical references (p. 141-147). / by Diane E. Di Massa. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1998. / Includes bibliographical references (leaves 80-85). / The first part of this thesis presents an analysis on the factors contributing to groundings when ships transit in and out of ports. The study has been part of a three-year project on "Ship Transit Risk". By verifying the grounding location database generated during the first two years of the project against the United States Coast Guard's grounding accident data, an updated database was established in this research. Within the frame of this new database, two factors were analyzed-tide and time of day. The results suggest that tide forecast error (predicted tide water level minus observed tide water level) had no significant effect as a risk factor, and that night navigation was far more risky than day navigation. The second part of this thesis presents a complementary point of view for risk analysis human factors. Many papers indicate that human beings are the most significant factors contributing to groundings. Nevertheless, few or no historical data sets recorded the information required for human factors analysis. Hence this part focuses mostly on literature review, introduces briefly the concept of the International Safety Management (ISM) Code, and some maritime regulations and final rules of OSHA (Occupational Safety and Health Administration). OSHA contributes to much research in human factors, yet few maritime related papers pay attention to it. Thus, we suggest that for further research on human factors, the collaboration of OSHA and maritime related research organizations such as USCG is necessary. The cooperative research would greatly contribute to the success of a risk model for groundings that may be also applied to other accident analysis. In addition, the exploration of a risk model for groundings may have a positive effect on the ISM code and OSHA's final rules in the future. / by Shu-chiang Lin. / S.M.