Yes Ari, That was a sad tradgedy. I don't know how engineers design ships to withstand seas when they do get over 50 feet. I've heard oceangoing vessels trade roll tendency for greater-frequency mechanical shock which yields stability, leaving eventual metal fatigue as a result. I read some more about these rogue waves here, which helped me understand the math a bit more with my limited simian brain: http://www.math.uio.no/~karstent/waves/index_en.html I also read the full Wikapedia site and looked into some of the ship dissapearences cited. Obviously, there is no proof for or against rogue wave causation with these incidents. There was a definition of about rogue waves, defining them as twice the height of the highest normally expected wave. For me. I'd always considered a true rogue wave as one at least three times the typically highest expected wave height with a preceeding cavernous trough that a vessel plows down into headlong or if encountered sideways, heels the vessel beyond the righting moment. Following the deep trough is a steep wave fave the provided the "coup d'etat" as it were. I can't reach any definitve conclusions on the issue but if marine ship designers are considering these extreme wave events in the context of designing ships for sea, well, obviously there's someone out there concerned. As some of the better research on rogue waves is coming out of Europe, I'm not sure why Tord is so dismisive. Not very faithful to his European peers. :-) Doug Lloyd > Hello Tord and all, > > please let me put a little bit light into the Estonia case, because it is > very widely discussed (I do not believe still living theories about a > conspiracy). The number of casualties is about 800: mostly Swedes, Finns > and Estonians. > > The ship had pretty huge construction and reconstruction problems in the > bow visor - and took continuos beating onto the bow during the final > night. > > There are no special information about a rogue wave, but rather > interesting statistics (from the report, > http://www.onnettomuustutkinta.fi/estonia/chapt13_1.html) : > > "The weather at the accident site at about 0100 hrs was rough but not > extreme. The wind was south-westerly, mean velocity 18 - 20 m/s. > Statistically, winds of such force occur five to ten times annually > during the autumn and the winter in the northern Baltic Sea. The > significant wave height was about 4 m. Generating a wave pattern with a > significant wave height of this magnitude requires wind of 15 - 20 m/ s > from S - SW for at least ten hours. > Numerous studies of wave statistics show that, if the significant wave > height is 4 m, one wave in a hundred will be higher than 6 m. A maximum > wave height is estimated as twice the significant height. > The weather forecast for the midnight hours predicted a significant wave > height of only 2.5 to 3.5 m whereas the actual height was about one metre > more. Even if the predictions had been correct, this would most likely > not have changed the way the passage was conducted." > > I remember still the awful morning, receiving the first news and images > of the disaster. > > Ari Saarto > - navigare necesse est - > http://asaarto1.blogspot.com/ > > > > > On 1. syys 2009, at 01:17, Tord S. Eriksson wrote: >> >> The Estonia ferry, that killed about as many Swedes as the Tsunami, >> or close to a thousand, also met a really big wave which ripped its >> bow off - could a rogue appear in a lake (very big, an inland sea)? *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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