Technology and Operations
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Re: Pressure hull construction - VIIC boats
Posted by:
Scott
()
Date: November 11, 2002 01:57AM
Sorry about leaving so soon after I started with the section on the hull, but company came and the little women said I must go. I will pick up where I left off. Please forgive.
(c) The overhead openings in the control room are compensated for by increasing the hull plating to 22mm, by trunking each opening and by fitting angles inside and outside the hull on each trunk. This sounds a little overdone. Further, as the openings make two frames discontinous. the adjacent through frames are increased to 200X15 (7.87"X.59").
(d) The patch in the engine room has double butt strap, double riveted, on the plating. Frames are butt, with double butt straps on the webs having 6 rivets on each side.
(e) The battery patch consists merely of a plate riveted to a frame about 1.5" thick which is welded onto the hull plating.
Within the pressure hull the forward and aft trim tanks, and the WRT tanks, are the only structural tanks designed for more than a gravity pressure head. The remaining structural tanks consist of four fuel oil tanks, the lubricating oil tanks, the fresh water tanks and the sanitary tanks.
The conning tower is a relatively small oval cylinder mounted vertically on the pressure hull. Plating thickness is 40mm (1.18"). Frames are vertical. The strucutre is closed at the top by an elaborate steel casting incorporating periscope and hatch rings, and ribs extending to the top of the frames. The specified plating material is identified as special Wh n/A, not further identifiable with available reference material. The cover casting is of chrome-molybdenum-vanadium steel.
The entrie pressure hull is welded except for the patches mentioned above. Butt joints are employed on the shell, and where heavier plating adajoins lighter plating, the heavier plating is scarfed to the lighter thickness at the weld. Where the shell is welded to the cast and bulkheads and where the conning tower plating joins the cover castring, the outer surfaces are flush, but the inner surfaces are not, and a fillet of weld metal has been built up from the plate to the thickness of the casting. Intermittent welding is used only on the stiffeners for the two light fabricated bulkheads. The cast type of pressure bilkhead is wleded to a ring on its periphery, which in turn is weled to the pressure hull. The door frames in these bulkheads are riveted.
Some time tomorrow I will wite about the Outer Shell.
Scott
(c) The overhead openings in the control room are compensated for by increasing the hull plating to 22mm, by trunking each opening and by fitting angles inside and outside the hull on each trunk. This sounds a little overdone. Further, as the openings make two frames discontinous. the adjacent through frames are increased to 200X15 (7.87"X.59").
(d) The patch in the engine room has double butt strap, double riveted, on the plating. Frames are butt, with double butt straps on the webs having 6 rivets on each side.
(e) The battery patch consists merely of a plate riveted to a frame about 1.5" thick which is welded onto the hull plating.
Within the pressure hull the forward and aft trim tanks, and the WRT tanks, are the only structural tanks designed for more than a gravity pressure head. The remaining structural tanks consist of four fuel oil tanks, the lubricating oil tanks, the fresh water tanks and the sanitary tanks.
The conning tower is a relatively small oval cylinder mounted vertically on the pressure hull. Plating thickness is 40mm (1.18"). Frames are vertical. The strucutre is closed at the top by an elaborate steel casting incorporating periscope and hatch rings, and ribs extending to the top of the frames. The specified plating material is identified as special Wh n/A, not further identifiable with available reference material. The cover casting is of chrome-molybdenum-vanadium steel.
The entrie pressure hull is welded except for the patches mentioned above. Butt joints are employed on the shell, and where heavier plating adajoins lighter plating, the heavier plating is scarfed to the lighter thickness at the weld. Where the shell is welded to the cast and bulkheads and where the conning tower plating joins the cover castring, the outer surfaces are flush, but the inner surfaces are not, and a fillet of weld metal has been built up from the plate to the thickness of the casting. Intermittent welding is used only on the stiffeners for the two light fabricated bulkheads. The cast type of pressure bilkhead is wleded to a ring on its periphery, which in turn is weled to the pressure hull. The door frames in these bulkheads are riveted.
Some time tomorrow I will wite about the Outer Shell.
Scott
