20:35 Sep 17, 2017 |
English language (monolingual) [PRO] Tech/Engineering - Ships, Sailing, Maritime / LNG tanker damage | |||||||
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SUMMARY OF ALL EXPLANATIONS PROVIDED | ||||
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4 -1 | le fond du système de sécurité a été déformé vers le haut |
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Discussion entries: 14 | |
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bottom of containment system set up le fond du système de sécurité a été déformé vers le haut Explanation: le fond du système de sécurité [de la double coque] a été déformé vers le haut the "containment system" is almost certainly a double hull - the inner one containing the cargo (LNG Liquefied natural gas), the outer hull designed to take the hit in case of collision and a empty space between them to avoid rupturing the inner hull when the outer hull gets deformed. "Le GNL s'il arrive à s'échapper, à la suite d'une rupture de la coque, s'évapore et peut, à la moindre étincelle, s'enflammer si le mélange air-gaz se trouve dans les limites de combustion (proportion de GNL comprise entre 5 et 15 %). Le navire lui-même ne peut pas exploser, car le GNL qui reste à l'intérieur du navire privé de comburant ne peut pas s'enflammer. Pour réduire ce risque, le méthanier est pourvu d'une double coque qui permet, en cas d'accident (échouage, collision), de limiter la probabilité qu'une cuve soit éventrée. La cuve elle-même comporte une double barrière remplie d'azote gazeux destiné à empêcher toute réaction avec l'oxygène atmosphérique. ..." https://fr.wikipedia.org/wiki/Méthanier bottom of containment system set up = the "bottom of containment system" [= the bottom of the outer hull] hit the sea bed and was pushed up beyond the limit of elastic deformation so stayed deformed (="set") in a position that is "up" from its initial shape. -------------------------------------------------- Note added at 5 hrs (2017-09-18 02:19:14 GMT) -------------------------------------------------- Table 4: Combined statistical data for LNG vessel accidents. Source: DNV Research. ... Date = 1979 Ship name = El Paso Paul Kayser (b. 1975) Activity = At sea Injuries/fatalities = No LNG spill = No Description = Stranded. Severe damage to bottom, ballast tanks, motors water damaged, bottom of containment system set up. Stranded in straits of Gibraltar. Was subsequently re-floated and towed to harbour to discharge cargo. Vessel was dry-docked when survey revealed extensive damage. Source = Houston Law Center, Colton, DNV report http://www.safedor.org/resources/SAFEDOR-D-04.03.01-2005-10-... -------------------------------------------------- Note added at 3 days7 hrs (2017-09-21 03:40:16 GMT) -------------------------------------------------- "Was subsequently re-floated and towed to harbour to discharge cargo. => "the content (LNG) did not escape from the tanks => the only part that got deformed/damaged was the bottom of the whole ship which is also the bottom of the space between the outer and inner hull. being hit from below, the outer hull can only bend "up". -------------------------------------------------- Note added at 14 days (2017-10-02 13:36:56 GMT) -------------------------------------------------- "déformé vers le haut" as confirmed by: "The impact caused some upward movement of the inner hull supporting the membrane cargo containment system but the membrane remained intact and no cargo was lost." http://www.giignl.org/sites/default/files/PUBLIC_AREA/Public... "This was a membrane ship, so pushing up the outer hull undoubtedly pushed up the containment system as one of the MSC83/INF.3 sources says. But apparently the cargo tanks were not breached." http://www.c4tx.org/ctx/job/cdb/cas_list/precis.php?id=19790... Thanks to Björn Vrooman. |
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