DATE / TIME: July 27, 2010, 9:30 a.m.
by telecom: Chris Barry (USCG-ELC)
– Rich Sonnenschein welcomed Panel members in attendance, including new member, LCDR Ron Caputo (USCG – MSC), and those participating via telecom, including new members Peter Nicol (Summit Metrology) and Dr. Ying Guang (“John”) Wang (Shanghai Jiao Tong University – School of Naval Architecture, Ocean, and Civil Engineering). Unfortunately, Dr. Wang did not have a good connection and, on top of the 12-hour time difference, soon had to depart. There were no corrections to the Minutes from the Panel’s meeting held on February 24, 2010 (linked to the corresponding date tab at
1.
Bill Peters briefed the Panel on preparations for the 53rd session of the SLF Sub-committee, to be held in London, UK, during the week of January 10, 2011 (see
for more detail), including:
• A paper from Norway to the MSC, proposing adoption of tow tripping criteria, not currently addressed in the Intact Stability (IS) Code.
• The IS Code correspondence group has prepared submissions for new generation Intact Stability; they will next run calculations, in order to validate the draft rules for real ships, and submit by October 2010.
• Questionnaires were sent out by the RO/RO Passenger Ferries Stability correspondence group. (Also, see the discussion under New Business.)
• In consideration of Passenger Ship damage survivability, recent full-scale leakage and collapse testing of hydro heads on NT doors, reveals that the bulkhead typically fails before the door assembly.
• An analysis is under way by the correspondence group on Subdivision and Damage Stability, to evaluate the subdivision equivalency of the OSV guidelines with respect to dry cargo ship probabilistic damage rules.
2.
Review of Stability-Related PNA Draft Chapters – DSTG coordinator, Chris Bassler, discussed DSTG activities:
• The most recent meeting was in February, and next meeting is scheduled for the afternoon on the same date as the subject Panel SD-3 meeting.
• There is constructive interaction with the IMO/SLF correspondence group for new generation Intact Stability.
• Bruce Johnson recently posted an updated Glossary of terms relating to dynamic stability to the egroup Library.
• The 11th International Ship Stability Workshop (ISSW) Proceedings, held June 21-23, 2010, in the Netherlands, are posted to the egroup Library.
• T&R sessions and three presentations planned for SNAME Annual Meeting.
• The DSTG’s three-year charter ends at the SNAME Annual Meeting in November 2010 (Seattle, WA). Chris will propose extending the charter by one year, due to ongoing developments.
3.
Review of Stability-Related PNA Draft Chapters –
• Bill Peters suggested that the Panel obtain electronic formatted copies of the stability-related PNA chapters (1, 2, and 3), with the goal of completing a four-year review cycle of content and format. There was a general consensus that this should be an ongoing function of the Panel.
(Action: Rich Sonnenschein to contact Randy Paulling for electronic copy)
4. Panel SD-3 and SNAME Web Page developments – Jane Louie discussed the ongoing progress with SNAME’s new web site:
• Any problems encountered should be reported to Jane Louie.
• Non-SD-3 and non-SNAME (e.g., ASNE) members can fill out a form to join the SD-3 egroup page.
• The functionality to create and use Subfolders would greatly enhance the Panel’s ability to organize material (e.g., by topic) on the egroup page.
(Action: Jane Louie to relay the Panel’s request to the developer)
5. Proposed Stability Guidance for Small Craft Designers
• Chris Barry has posted a first-cut, draft outline of the proposed Guidance document for Panel review and comment, particularly on items that should either be added or not included. Chris is also seeking volunteer contributors, to run analyses, develop graphics, etc.
• Panel discussion indicated a general consensus on the purpose, i.e., to offer meaningful training that is accessible to non-degreed designers, in order to instill an appreciation of the technical approach and importance of stability analysis, as well as some of the available tools.
• Hydromax (by MaxSurf) is widely used in the academic environment, and a good software prospect for demonstration purposes.
• One suggested demonstration might illustrate the potential pitfalls of cross-curve data in the analysis of small craft stability, without proper attention to hull form irregularities and attendant trim.
(Action: All are requested to review and comment, via the egroup page; if interested in contributing analysis or graphics support, contact Chris Barry by email)
(Action: Chris Barry to also invite the Sailing Craft Committee to review the draft outline)
New Business:
• Bruce Johnson briefly discussed the recent, abrupt capsizing of the Canadian training sail ship, Concordia, in whose aftermath all were rescued. Bruce noted the possible irony that if the vessel had more internal subdivision, including WT doors, this would have greatly impeded the evacuation and rescue process. It is not clear, as to whether the ship would have righted itself, assuming it had greater subdivision.
•
There was a discussion of a controversy regarding the adequacy of RO/RO Passenger Ship damage safety requirements under the new probabilistic rules, vs. the old deterministic rules. Many on the Panel agreed that the probabilistic rules have become so complex that a naval architect lacks an intuitive grasp of what he/she is dealing with in designing for damage safety. Bill Peters offers this discussion of the survivability issue:
i. The deep draft ‘A’ can’t be less than 0.9R, so there is generally good ‘A’ throughout all three drafts. The issue really has to do with the survival characteristics of cases where 1>s>0 and the minor damage requirements (new regs. SOLAS II-1/8). Very generally, the big issue is the RoPax designs with long lower holds (LLH) (i.e. below the bulkhead deck) that can have long’l bulkheads close to almost B/10 from the ship’s side. In cases where the LLH is assumed penetrated, the ship experiences substantial sinkage that reduces freeboard and affects the computed ‘s’ for that case. Hence, such a case could have reduced stability in which higher sea states could cause rapid capsize. In my view, there is still more research that needs to be done to really assess in failure cases the risk of rapid capsize.
ii. From a technical view, one would look more closely at the likelihood of rapid capsize in the s < 1 cases, but, in the end, the resolution may very well be consideration of increasing ‘R’ which would tend to raise overall survivability.
Adjournment / Next Meeting - The meeting was adjourned at 11:30 am; the next meeting is tentatively scheduled for 9:30 AM on Tuesday, October 5th, at the DOT Building – in conjunction with a meeting of the DSTG later that afternoon.