It has the reverse principal of the Q Tank and was fitted after the Scorpion and Thresher disasters. Vast amount of air gets us up quick. Apparently the OOW has a big red knob to pull down to activate.
It has often been used by the USN to impress Pollies and Jouno's. Unfortunately it precludes you knowing if any ship is in the way unless you have a very firm sonar contact. Then this happened with a US Pollie on the helm/planes.
HONOLULU, Hawaii (10 Feb 2001) -- Nine Japanese people are still missing following Friday's collision between the USS Greeneville and the Ehime Maru, 14km off Honolulu, Hawaii.
The Ehime Maru was halfway through a marine studies training voyage for Japanese students and teachers. Four high school students, two teachers and three crew are missing and feared drowned.
According to US Navy officials, the nuclear-powered submarine struck and sank a Japanese trawler during an emergency surfacing drill.
The USN practice of doing that belly flop surface comes from the WW2 fleet boats that had a poor HP air capacity, and developed the airless surface, airless start process. First you drive the boat out of the water with the main vents open and shut them when the boat is as far out of the water as it will get, this gets enough air into the ballast tanks to keep the boat on the surface. The tanks can then be toppedup with the LP blower. Then you motor flat out on one shaft letting the other one trail, once you have worked up some speed you pull in the engine clutch on the trailing shaft and hope it kicks the deisel over enough to start it. Repeat process on second shaft.