Technology and Operations
This forum is for discussing technological & operational matters pertaining to U-boats.
Re: Sophisticated sonar.
Posted by:
Seeker
()
Date: July 25, 2009 06:09PM
After absorbing Rossler’s book in detail, it references such a design in WW-I with a traversable torpedo rack, similar to Torpedoboot design, it seems.
Upon deeper reading I may have been to hasty in my assessment of the speed possibilities by altering the conning tower. The 25% reduction was in resistance, resulting in about a 7% increase in speed [since any power increase is raised to the 1/3 power]. Apparently that stream lining was investigated by the Norwegians post war with a captured Uboat. It only allowed a 1/2 knot increase in top speed but greatly improved the Uboat underwater handling characteristics.
There was a plan to upgrade the type VII for higher speed late in the war . This involved tripling the electrical generator and using the ammo bunker area plus the bottom row of reserve torpedos to greatly increase battery capacity. Combined with removing the surface armament and stream lining the conning tower, a top speed of 12 knots was possible.
However the author points out, just by installing a variable pitch propeller and adjusting its revolutions to the electrical generator, this same top speed could achieve. Apparently the Type VIIC 42 design had a variable pitch propeller so maybe this could be done to that model? With the entire above-mentioned stream lining plus closing down 1/2 of the flooding slits, its possible to get a top submerged speed of 14-15 knots.
While the Type XXI was supposed to reach 17 knots initially, the actual models only reached 15.9 knots in sustained test runs at the end of the war, not that much higher than the above-mentioned top speed. By tinkering with these models [increased stream lining bridge and reducing the flooding slits by 1/2 and removing the flak turrets] it did allow the XXI top speed adjustment to creep back up to 17.2 knots.
One final point, Rossler’s book reports that the V-80 and the first two peroxide boats built, conducted 300 test runs between them with out any reported serious accidents. Perhaps this Walter peroxide engine reliability issue, is over stated?
Upon deeper reading I may have been to hasty in my assessment of the speed possibilities by altering the conning tower. The 25% reduction was in resistance, resulting in about a 7% increase in speed [since any power increase is raised to the 1/3 power]. Apparently that stream lining was investigated by the Norwegians post war with a captured Uboat. It only allowed a 1/2 knot increase in top speed but greatly improved the Uboat underwater handling characteristics.
There was a plan to upgrade the type VII for higher speed late in the war . This involved tripling the electrical generator and using the ammo bunker area plus the bottom row of reserve torpedos to greatly increase battery capacity. Combined with removing the surface armament and stream lining the conning tower, a top speed of 12 knots was possible.
However the author points out, just by installing a variable pitch propeller and adjusting its revolutions to the electrical generator, this same top speed could achieve. Apparently the Type VIIC 42 design had a variable pitch propeller so maybe this could be done to that model? With the entire above-mentioned stream lining plus closing down 1/2 of the flooding slits, its possible to get a top submerged speed of 14-15 knots.
While the Type XXI was supposed to reach 17 knots initially, the actual models only reached 15.9 knots in sustained test runs at the end of the war, not that much higher than the above-mentioned top speed. By tinkering with these models [increased stream lining bridge and reducing the flooding slits by 1/2 and removing the flak turrets] it did allow the XXI top speed adjustment to creep back up to 17.2 knots.
One final point, Rossler’s book reports that the V-80 and the first two peroxide boats built, conducted 300 test runs between them with out any reported serious accidents. Perhaps this Walter peroxide engine reliability issue, is over stated?
