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Wolfstriked · 06-26-11, 08:40 AM

Is it really true that a Uboat sinks when at zero speed.....I am asking about periscope depths mainly?I found this out about uboats and I would think that the DO would make exceptions for maintaining periscope depth and then blow negative tank when diving deeper for the safety reasons,so that they really would sink at slow speeds???

""n diving quickly, the negative tank is important. By flooding this tank the submarine becomes negatively buoyant. This gets the boat under water quicker. Once submerged, though, the negative tank will be blown or pumped out, to restore neutral buoyancy. You want to be heavier than water as you dive, but you don't want to stay that way once you're under. If the negative tank remained full and all power was lost the boat would quickly sink below crush depth and kill everyone aboard. The safety tank, which is normally kept fully flooded while submerged, is designed to hold the same volume of water as the conning tower. If the conning tower floods and has to be abandoned, the safety tank may be blown dry to compensate.""

Another point from same page

""Blow negative: When the depth is 15 feet short of the desired depth, the flooded negative tank is blown to restore neutral buoyancy. This tank is never blown completely dry at sea in order to avoid sending air bubbles to the surface. Once the flood valve is closed, the excess air pressure is vented into the hull.""

06-26-11, 08:40 AM	#15
Wolfstriked Grey Wolf Join Date: Apr 2011 Posts: 756 Downloads: 237 Uploads: 0	Is it really true that a Uboat sinks when at zero speed.....I am asking about periscope depths mainly?I found this out about uboats and I would think that the DO would make exceptions for maintaining periscope depth and then blow negative tank when diving deeper for the safety reasons,so that they really would sink at slow speeds??? ""n diving quickly, the negative tank is important. By flooding this tank the submarine becomes negatively buoyant. This gets the boat under water quicker. Once submerged, though, the negative tank will be blown or pumped out, to restore neutral buoyancy. You want to be heavier than water as you dive, but you don't want to stay that way once you're under. If the negative tank remained full and all power was lost the boat would quickly sink below crush depth and kill everyone aboard. The safety tank, which is normally kept fully flooded while submerged, is designed to hold the same volume of water as the conning tower. If the conning tower floods and has to be abandoned, the safety tank may be blown dry to compensate."" Another point from same page ""Blow negative: When the depth is 15 feet short of the desired depth, the flooded negative tank is blown to restore neutral buoyancy. This tank is never blown completely dry at sea in order to avoid sending air bubbles to the surface. Once the flood valve is closed, the excess air pressure is vented into the hull."" Last edited by Wolfstriked; 06-26-11 at 08:51 AM.