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Talk:Petronius (oil platform)

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Contradiction with "List of the world's tallest structures" article

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I don't understand :"..when including underwater structures -- otherwise it would be Canada's CN Tower" this not agree with: http://en.wikipedia.org/wiki/List_of_the_world%27s_tallest_structures PIDARD. -- unsigned by 200.123.147.90 at 21:51, 14 March 2006.

The CN Tower is the "tallest free-standing tower in the world", which that list you linked to agrees with. 63.82.34.140 22:51, 10 April 2006 (UTC)[reply]

For comparision with its total weight and the strength of other above and below water structures it would be interesting to say what boyancy the structure gains from its displacement of water Rod57 (talk) 10:54, 9 September 2008 (UTC)[reply]

Steel has a density of around 7.9 t/m³, Water 1 t/m³. Therefore a structure under water only has to support roughly 7/8ths = 87.5 % of its weight in air. (To be precise you'd have to take into account the displaced mass of air also, but in practice, with a density of ca. 0.0013 t/m³, this is insignificant.) Now this calculation only holds true for the structure itself and doesn't look at the "payload", i.e. the whole mass of an oilrig above water, which would need to be supported fully in both cases. Also I would expect the lateral forces from water currents to be higher than wind forces in air, which means you'd still need a stronger strucure than you might at first think. But all in all I find it quite silly to include an underwater tower in a list of tallest structures. Or else you might say that Mauna Kea is taller than Mt Everest. --BjKa (talk) 13:43/13:49, 8 July 2016 (UTC)[reply]