Re: [PSUBS-MAILIST] ambient ballast control

["Jay K. Jeffries" <bottomgun@mindspring.com>]

If you have completed your weight and balance calculations correctly, you should be very close by a few pounds.  In an old Kitteredge publication or correspondence from the mid-70s, I remember him relating that he was only off by about 2-3 pounds when he first lauched the K-250 or -350 which was quickly corrected with some dive weights.  It is better to be slightly positive as this can always be easily fixed with moveable ballast (a good idea especially with changing operator's weight).  In the case of a 2-man running with only the operator, a 2nd hard trim tank sized equivalent to the missing passenger is required or a lot of hard ballast must be loaded.

 

As to Skeet's earllier question as to how positive you should be, this is a two-edged sword where the amount of positive bouancy must be balanced by the additional energy (ie battery capacity) required to drive the boat under and keep it under.  Thus you only want a very small amount of positive buoyancy...enought o get you to the surface on a loss of power but it doesn't have to be fast.  A flooding or fire (2 greatest nightmares of a submariner) is another issue; this is were you would do an emergency blow of all tanks from depth and drop the emergency weight as quickly as possible.

R/Jay

Skeet,

I've thought about this very problem and came to the conclusion that I will get the "math" as close as possible, then leave it to sea trials for the "fine tuning".

Let's see if someone else has a better answer though.

Joe

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