A stall in the context of the original post is defined as follows:
An aerodynamic (or in this case hydrodynamic) loss of "lift" caused be exceeding an airfoil's (or hydrofoils') cricitcal angle of attack.
a lot of people screw this up. it has nothing to do with weight or speed.
the situation uncle goose describes is a matter of the dive planes (lift) not being able to overcome the negative buoyance of the submerged u-boat (weight)... what he described is NOT a "stall".
uncle goos is partially correct in his statement; that dive planes are responsible for setting a dive angle, and fine tuning the small scale and immediate trim of the u-boat
... but in no way do they make large adjustments to depth... high pressure air or an influx of sea water cause depth changes to occur NOT dive planes.
the situation Puster Bill is describing the way i understand it is as follows:
>>set a steep ascent to surface at high speed... while on the way up, drop the speed down to zero... will the submarine's dive planes "stall" and subsequently cause the sub to drop or sink?
No... they wont. their effectiveness will be negated by the drop in speed, and the submarine will not rise as quickly.
however, as high pressure air is sent to the MBT, the submarine will rise - irregardless of the dive planes.
__________________
|