November
2005
Table
of Contents:
Chesapeake Section |
|
Northern California Section |
|
November
2005
|
|
Chesapeake
Section September 7, 2005 Lady D Casualty Outcome: Research into Pontoon Vessel Stability On September 7th, Dr. George Borlase presented a summary of research performed to compare the different stability standards applicable to pontoon passenger vessels like the Lady D. Forty-five interested members and guests attended the Section’s dinner meeting at the Washington Navy Yard. Dr. Borlase, currently of the Johns Hopkins University Applied Physics Lab (APL), previously served on active duty at the Coast Guard Marine Safety Center in Washington, D.C., and worked on numerous passenger vessel accident investigations, including the capsizing of the passenger pontoon vessel Lady D in Baltimore Harbor in March 2004. The paper’s co-author, LT Eric Cooper, formerly worked in the Naval Architecture Division at Coast Guard Headquarters, but could not attend due to Hurricane Katrina relief efforts.
The author noted that of the four stability standards reviewed – the pontoon simplified stability proof test in the Code of Federal Regulations (CFR), the intact righting arm requirements in the CFRs, the ISO standard, and the ABYC standard, the pontoon simplified stability proof test was the most restrictive in terms of the number of passengers carried with few exceptions. Proposals were made for new restrictions on the vessel’s design, including beam, draft, and pontoon diameter, and the maximum wind speed so that the pontoon simplified stability proof test could more accurately reflect the vessel’s stability.
The author commented that the National Transportation Safety Board (NTSB) had issued a preliminary finding that the average passenger onboard the Lady D weighed significantly more than the simplified stability proof test assumed. At the T&R meeting held during the 2005 SMTC in Houston, consideration was given for the formation of a 15th Ad Hoc Panel, which would provide technical support for activities associated with determining the impact of an increase of the average passenger weight on passenger vessels.
The technical presentation, which was approved for the award of one professional development hour for PE continuing education, was followed by a spirited discussion on pontoon vessel stability.
October
12, 2005 High Speed Craft Aluminum Ultimate Strength Design At the meeting held on October 12th, Dr. Matthew Collette presented a paper on ultimate limit state structural design techniques and reliability-based design techniques that focused on a new generation of large high-speed aluminum vessels. Many of approximately 35 members and guests participated in a lively and freely exchanging discussion after the technical presentation at the Washington Navy Yard meeting. In recognition of its technical content, the presentation was approved for the award of one professional development hour for PE continuing education credit. The Section paper he provided to the members featured some of the work Dr. Collette did to earn his Doctoral degree at the University of Newcastle; he is now with SAIC in Annapolis, Maryland.
The Section paper looked at improved structural engineering methods for large, oceangoing high-speed aluminum vessels. Ultimate strength and reliability-based approaches offer the potential for a rational approach to optimizing and approving structural designs for these vessels, but suffer from increased complexity and data that may not be available. Dr. Collette summarized the key material differences between aluminum and steel for structural designs, and also the differences between the aluminum alloys commonly used in marine construction. Existing ultimate strength methods for plates, panels, and the hull girder were presented and compared to experimental test data. Aluminum-specific aspects of the structural response were also highlighted. The data required for reliability-based design also was presented and the areas in which uncertainty data is lacking was highlighted. Ideas were presented for future work in aluminum structures, including further studies on the effects of welds, strength prediction for complex profiles made possible by ease of extruding aluminum, and the influence of the increased use of truss-like structures in large multi-hull vessels.
A particular feature of this year’s technical meetings is a short presentation of various SNAME activities which all members should be aware. Prior to Dr. Collette’s technical presentation CAPT Paul Roden outlined the “facts” associated with our declining membership; he then outlined the plans that the Membership Committee has developed for retaining members, and increasing the linkages between student members and SNAME mentors. Paul Roden is the Functional Vice-President for Membership. We also welcomed the newly appointed Technical Director of ASNE, Mr. David Stevenson, to our technical meeting.
Northern
California Section October 12, 2005 Designing Ships for Pirates of the Caribbean II An enthusiastic audience drawn from the SNAME Northern California Section, ASNE Golden Gate Section, and student sections at the University of California, Berkeley and California Maritime Academy gathered on October 12, 2005 for an enjoyable program concerning ship design for Pirates of the Caribbean II. Mr. Andy Davis, Naval Architect and President of Tri-Coastal Marine, discussed the work of his firm in designing three full size ships for the film. Pirates of the Caribbean II is purportedly the most expensive movie made to date with a budget of $400 million dollars. Mr. Davis summarized the design process and presented photographs of the vessels during construction. The three vessels were built with an innovative wood/steel composite method, and are operational in varying degrees.
Black Pearl (Captain Jack Sparrow’s flagship) was built over an existing 1970’s era steel crewboat. It is fully operational and has traveled from Bayou LaBatre to Dominica in the West Indies and Freeport in the Bahamas.
Edinburgh is a full size replica of the Bounty built on two barges, which is to be broken in half by a sea monster prior to this presentation. Flying Dutchman is a 500-ton ghost ship, which was built in three modules. A special motion basin was excavated on the sea front in the Bahamas. The vessels are attached to active tethers in the floor of the basin for maneuvering and simulated motion in waves.
|
