Technology and Operations
This forum is for discussing technological & operational matters pertaining to U-boats.
Re: Pressure Hull Material
Posted by:
Scott Sorenson
()
Date: September 16, 2008 04:14PM
Part II
In addition to the dished end bulkheads of cast steel, four other dished cast bulkheads are fitted, dividing the pressure hull into five pressure compartments. These bulkheads are 22mm thick; but material specifications, while inknown, are believede to be German cast steel 45.81 per KM 9106.
Further subdivision is provided by two light fabricated bulkheads, one in the battery compartment forward, and the other separating the maneuvering and engine space in the machinery compartment aft, These are disigned for a pressure differential of 3 psi only, but in practies serve no pressure purpose because they have so many non-tight opening.
Large openings in the pressure hull consist of the two torpedo hatches, one galley hatch, one engine room hatch, ad openings overhead in the control room for conning tower hatch and two periscopes. There is also one removable patch in the way of the engine room and other overhead in the battery compartment.
Compensation for these openings is obtained in a number of different ways. First - For the torpedo hatches, a doubler (in some vessels a single thicker plate) is fitted, increasing the plate thickness from 17mm normal to 38mm (1.49 inch). The frames are cut in the way of the hatches, and are fitted with bearing pieces at the ends, against which strongbacks are wedged and secured in position by toggle pins. Second - The galley and engine room hatches have no compensation other than their trunks, which are tubes wuth 20mm (,79 inch) walls. Third - The overhead openings in the control room are compensated for by increasing the hull plating to 22mm, by thrunking each opening and by fitting angkes inside and outside the hull on each trunk. This sounds a little overdone, Further, as the openings make two frames discontinuous, the adjacent through frames are increased to 200X15 (7.87 inch x.59 inch). Fourth - The patch in the engine room has double butt strips, double riveted, on the plating. Frames are butted, with double butt strips on the web having 6 rivets on each side. Fifth - The battery patch consists merely of a plate riveted to a frame about 1.5 inch thick which is welded into the hull plating.
More to come later.
In addition to the dished end bulkheads of cast steel, four other dished cast bulkheads are fitted, dividing the pressure hull into five pressure compartments. These bulkheads are 22mm thick; but material specifications, while inknown, are believede to be German cast steel 45.81 per KM 9106.
Further subdivision is provided by two light fabricated bulkheads, one in the battery compartment forward, and the other separating the maneuvering and engine space in the machinery compartment aft, These are disigned for a pressure differential of 3 psi only, but in practies serve no pressure purpose because they have so many non-tight opening.
Large openings in the pressure hull consist of the two torpedo hatches, one galley hatch, one engine room hatch, ad openings overhead in the control room for conning tower hatch and two periscopes. There is also one removable patch in the way of the engine room and other overhead in the battery compartment.
Compensation for these openings is obtained in a number of different ways. First - For the torpedo hatches, a doubler (in some vessels a single thicker plate) is fitted, increasing the plate thickness from 17mm normal to 38mm (1.49 inch). The frames are cut in the way of the hatches, and are fitted with bearing pieces at the ends, against which strongbacks are wedged and secured in position by toggle pins. Second - The galley and engine room hatches have no compensation other than their trunks, which are tubes wuth 20mm (,79 inch) walls. Third - The overhead openings in the control room are compensated for by increasing the hull plating to 22mm, by thrunking each opening and by fitting angkes inside and outside the hull on each trunk. This sounds a little overdone, Further, as the openings make two frames discontinuous, the adjacent through frames are increased to 200X15 (7.87 inch x.59 inch). Fourth - The patch in the engine room has double butt strips, double riveted, on the plating. Frames are butted, with double butt strips on the web having 6 rivets on each side. Fifth - The battery patch consists merely of a plate riveted to a frame about 1.5 inch thick which is welded into the hull plating.
More to come later.
