[PSUBS-MAILIST] G.L. rules Arrangement for Diving/Ballasting, Control/Compensating & Trimming

[jimtoddpsub at aol.com]

Hi Alan,
Thanks for posting that.  What all does "compensating tanks" refer to? 
Best regards,
Jim



-----Original Message-----
From: Alan James <alanlindsayjames at yahoo.com>
To: psubs.org <personal_submersibles at psubs.org>
Sent: Fri, Jan 10, 2014 5:37 pm
Subject: [PSUBS-MAILIST] G.L. rules Arrangement for Diving/Ballasting, Control/Compensating & Trimming



Hi all,
This is my G.L. summary of Diving/Ballasting, Control/Compensating & Trimming.
It builds a little on a previous section "Stability & buoyancy".
   All the ballasting controls & systems have to work under previously specified heel & trim requirements. Including when one main ballast tank is damaged.
   It has to be possible to check these systems prior to diving.
   The sub must be able to surface after the failure of a compensating tank.
   Flooding & bilge openings are to be protected with grids, filters or strum boxes to stop the entrance of foreign matter.
   All the operating units for controlling positive & negative buoyancy are to be grouped together & clearly marked on the control consul. This control consul is to have indicating instruments showing depth & trim.
   Separate shut off valves are required for each ballast tank.
   The vent valves are to be designed in such a way as to prevent unintentional opening.
   Where diving tanks have flooding holes without means of closure, double shut-off
valves "May" be stipulated for the vent pipe.
   The blowing line for each tank has to have a separate shut off.
   Blowing the tanks cannot cause an excessive over-pressure.
   Where the diving tanks are pumped out there needs to be a closure valve & back up bilge pump. No excess under-pressure can be caused.
   Compensating tanks are to be designed big enough for all the changes in
buoyancy plus 10%
   Compensating tanks need contents gauges to give continuous readings.
   The compensating tank vent pipes need to be wide enough for maximum 
inflow / outflow and designed so that water can't flow from them unnoticed in to the hull.
   The volume of the trimming tanks is designed in such a way that all planned trimming situations can be adjusted by combined filling & emptying of the various tanks.
Alan










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