[BITList] Flume tanks

[Michael Feltham]

During my time with Denholm's I served on an 70/80000 tanker that had holes cut in the two longitudionel bulkheads for the midship cargo tanks.  During ballasting after tank cleaning, invariably the ship would list one side or the other until the holes in both bulkheads were covered. During the ship's life they reduced the freeboard , consequently the midship cargo tanks were mainly full thus cancelling the flume tank effect.  The ship had no bilge keels !

Mike
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On 12 Jan 2010, at 13:35, John Feltham wrote:



Begin forwarded message:



Still using flume or stablizer tanks on offshore support and dive vessels in the '90s+.  They are fitted across the full width of the ship,  with later vessels sometimes having them installed  just below the bridge!    They are part filled with ballast water  and  have baffles across the tanks which makes the surge of water get out of sync. with the ship's roll and so progressively reduces the roll.  These flatbottomed ships are notorius for their rolling - down to 4 seconds for a complete cycle,  without flume tanks operating.
 
As Frank says,  great care has to be taken to get the levels just right in the tanks otherwise they can get into sinc with the vessel's roll.  Also necessary to check the tanks frequently to make sure the baffles don't work loose.
 
Their effectiveness can be quite dramatic but only if all criteria are met including a regular beam swell.  Otherwise they can be a noisy nuisance.
Chris


ooroo

Bad typists of the word, untie.




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