Sub physics - experts needed

[TopTorp '92]

When that thread (Dr. Sid) goes tactical let me know as I'd like to provide input.

By far this has been among the most interesting threads I have read in a long time. Only Bubblehead Nuke can provide the level of detail I see here.

However I must make a tactical insertion here because there is after all a tactical problem associated with all the engineering discussion. Earlier BH Nuke claimed that “[w]hen submerged there is NO AIR in the MBT's. You open the MBT vents and close them when you are fully submerged and the tanks are full of water.”

In fact we did cycle MBT vents once submerged to 150’. The idea was to remove trapped air as BH Nuke correctly identifies. Unfortunately there is still some air remaining in the tanks and the effects of this trapped air may not be detected on sonar until the ship makes a depth excursion or turns with enough roll to make the air bubbles shift causing the noise-tactical problem. Not only would we need to cycle vent valves once submerged but also we would need to complete an excursion combined with an additional vent cycle to provide an added measure of certainty in the removal of trapped air in the ballast tanks.

Finally this adjustment requires a tactical trade-off in that any self-induced noise may be detectible on another sonar platform. That’s why we always cycled vents once submerged to 150’ but had to live with the possibility that yet more air bubbles may appear after returning to shallow depth (150’ or above) after a period of operations at deeper depth.

TopTorp