SUBSIM Radio Room Forums - View Single Post - Realism- and gameplay-related hardcode fixes for SH3.EXE

Tom · 01-17-12, 12:27 AM

Ok, after reading the VIIC manual and the reports of americans who examined captured u-boats more closely, this is how I understand pumping and blowing water out worked:

The main ballast tanks (about 103 cubic meters), main ballast and reserve fuel oil tanks (49 m3), and negative buoyancy tanks (quick dive tanks, 4 m3) were to be blown, not pumped.

The regulating tanks (15 m3) and trim tanks (7 m3) could be pumped or blown, and the regulating reserve fuel oil tanks (9 m3), as well as the torpedo compensation tanks (14 m3) could only be pumped.

Pumps were also used to drain water that had leaked inside the rooms and bilge of the submarine.

The main method of gaining positive buoyancy in order to surface the boat was blowing of the main ballast tanks. The tanks were not blown empty, only enough was blown to start the boat rising. As the boat would become lighter as it rose, it rose all the way to the surface unless more weight was later taken on board. When the conning tower was above water, the diesels were started, and diesel exhaust was then used to blow the main ballast tanks empty.

When diving deep, one of the regulating tanks was kept at a pressure of 12 atm or so, to enable pumping of water out even when the depth was 200+ meters. The idea was to pump water that had leaked inside the boat first into this regulating tank, with a pressure difference of 11 atm (12 atm in the tank and 1 atm in the boat), and then from the regulating tank to main ballast tank 3 (or directly off the boat), with a pressure difference of another 11 atm if the depth was 230 meters, for example.

Thus, if blowing the main ballast tanks was not possible for whatever reason, the water possibly inside the boat and inside the regulating and trim tanks could be pumped out in order to surface the boat.

The VIIC had two compressiors to create the compressed air, one working on diesel, one on electricity. Earlier boats (VIIB) had two electric compressors. Compressing air, if I understand correctly, could only be done on the surface anyway, because the air had to come from somewhere, and that somewhere is from outside the boat.

01-17-12, 12:27 AM	#3063
Tom Gunner Join Date: Oct 2006 Location: Finland Posts: 97 Downloads: 10 Uploads: 0	Ok, after reading the VIIC manual and the reports of americans who examined captured u-boats more closely, this is how I understand pumping and blowing water out worked: The main ballast tanks (about 103 cubic meters), main ballast and reserve fuel oil tanks (49 m3), and negative buoyancy tanks (quick dive tanks, 4 m3) were to be blown, not pumped. The regulating tanks (15 m3) and trim tanks (7 m3) could be pumped or blown, and the regulating reserve fuel oil tanks (9 m3), as well as the torpedo compensation tanks (14 m3) could only be pumped. Pumps were also used to drain water that had leaked inside the rooms and bilge of the submarine. The main method of gaining positive buoyancy in order to surface the boat was blowing of the main ballast tanks. The tanks were not blown empty, only enough was blown to start the boat rising. As the boat would become lighter as it rose, it rose all the way to the surface unless more weight was later taken on board. When the conning tower was above water, the diesels were started, and diesel exhaust was then used to blow the main ballast tanks empty. When diving deep, one of the regulating tanks was kept at a pressure of 12 atm or so, to enable pumping of water out even when the depth was 200+ meters. The idea was to pump water that had leaked inside the boat first into this regulating tank, with a pressure difference of 11 atm (12 atm in the tank and 1 atm in the boat), and then from the regulating tank to main ballast tank 3 (or directly off the boat), with a pressure difference of another 11 atm if the depth was 230 meters, for example. Thus, if blowing the main ballast tanks was not possible for whatever reason, the water possibly inside the boat and inside the regulating and trim tanks could be pumped out in order to surface the boat. The VIIC had two compressiors to create the compressed air, one working on diesel, one on electricity. Earlier boats (VIIB) had two electric compressors. Compressing air, if I understand correctly, could only be done on the surface anyway, because the air had to come from somewhere, and that somewhere is from outside the boat.