[BITList] Drillship stuff

[david harvey]

On the "Rig Seismic", built in Denmark and ice strengthened, we had flume tanks designed to carry fuel. There were no baffles as such but heavy fore and aft frames in the tanks, which would never come loose. The theory being that the solid frames were of the same square footage as baffles and the open space was the same square footage as the openings in the baffles, so why bother with baffles.. Does that make sense. In any event the Australian Department of Transport said that we couldn't use them as there were no written instructions/manual on board as to how to use the tanks

Except that we did an extended voyage into the Antarctic and we needed the extra fuel capacity so we were given an exemption for that voyage into some of the most dangerous waters on earth. Beats me.

I've described previously what happened on that voyage when we fell into a hole in the 'Screaming Sixties', so won't go into that again. Another place I wouldn't volunteer to go again.

'Twas on that ship I did my last stability calculation and it was the last time I used a sextant in anger, to measure the height of an iceberg.

Dave
  ----- Original Message ----- 
  From: John Feltham 
  To: BITList 
  Sent: Tuesday, January 12, 2010 9:35 PM
  Subject: [BITList] Drillship stuff






  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.










------------------------------------------------------------------------------


  _______________________________________________
  To unsubscribe from this email List, send an email to:
  BITList-unsubscribe at lists.bcn.mythic-beasts.com

  BITList mailing list
  BITList at lists.bcn.mythic-beasts.com
  http://lists.bcn.mythic-beasts.com/mailman/listinfo/bitlist

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.bcn.mythic-beasts.com/pipermail/bitlist/attachments/20100112/c8a1cba2/attachment.shtml