[PSUBS-MAILIST] Stability & Buoyancy

[Marc de Piolenc]

Good point. Stability criteria on the surface and submerged are very 
different, the latter being much easier to assess. Stability during 
transition from one to the other, with the main ballast tanks half full 
and water free to slosh, is very complex to assess, but very important 
for the very reason given. I haven't yet found a text that does anything 
more than mention this problem, however!

Marc

On 11/30/2013 8:40 AM, Alan James wrote:
> Hi everyone,
> While reading through some background info for the G.L.
> certification document, I came across this link with a good
> explanation of stability & buoyancy
> http://maritime.org/doc/fleetsub/chap5.htm
> There is a phenomena described, where submarines can be
> unstable to the point of turning over during the transition from
> surface to diving & vice versa.
> This has to do with the centre of buoyancy moving upward past
> the centre of gravity. As it approaches the centre of gravity the
> submarine is at it's most vulnerable point.
> This would be different for individual designs & a worry if
> you dropped your emergency drop weight.
> I had been told by a pilot that he never stuffed around while
> descending & liked to drop as quick as he could.
> I didn't have a full understanding of this & thought there may
> be others in the same boat.
> Regards Alan
>
>
>
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