Technology and Operations
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Re: Pressure hull construction - VIIC boats
Posted by:
Scott
()
Date: November 10, 2002 06:38PM
General Hull Sturcutural for the Type IXC/40
The vessel consists of a cylindrical pressure hull with truncated conical sections at the ends and cast end bulkheads, a conning tower of oval horizontal section with a cast top, a system of exterior ballast and fuel tanks enclosed in a ship-shaped envelop, and a light superstructure with accompanying conning tower fairwater and bridge. A box keel is fitted below the pressure hull. The designer's submergence depth is 100m (328').
The Pressure Hull
The cylindrical pressure hull has a diameter of 4400mm (14.42') and is made of 18mm (.73") steel with inside bulb tee frames 200X11 (7.88" web depth X .43" web thickness) on 700mm (27.56") centers. The plating is gradually reduced throughout the tapered sections fore and aft to 16mm (.63"), and the frames are correspondingly reduced to 130X9 (5.12" X .35"). Frames spacing remains unchanges in the tapered sections.
The specification for the pressure hull plating and frames calls for a tensile strength of 74000 psi with a yeild point of 513000 psi. The steel is known as No. 52; the specification for plates is KM 9104, and for frames is KM 9103.
Framing is modified in the way of the main motors, to provide clearance, by substuting double frames 160X9 (6.30"X.35") for normal 200X11 frames.
In addition to the dished end bulkheads of cast steel, four other dished cast bulkhead are fitted, dividing the pressure hull into five pressure compartment. These bulkhead are 22mm thick; but material specifications, while inknown, are believed to be German cast steel 45.81 per KM 9106.
Further subdivision is provide 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 desinged for pressure differential of 3 psi only, but in practice serve no pressure purpose because they have so many non-tight openings.
Large openings in the pressure hull consist of the two torpedo hatches, one galley hatch, one engine room hatch, and 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.
Compersation for these openings is obtained in a number of different ways:
(a) 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"). 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.
(b) The galley and engine room hatches have no compensation other than their trunks, which are tubes with 20mm (.79) walls.
I have to go for now, will write more later
Scott
The vessel consists of a cylindrical pressure hull with truncated conical sections at the ends and cast end bulkheads, a conning tower of oval horizontal section with a cast top, a system of exterior ballast and fuel tanks enclosed in a ship-shaped envelop, and a light superstructure with accompanying conning tower fairwater and bridge. A box keel is fitted below the pressure hull. The designer's submergence depth is 100m (328').
The Pressure Hull
The cylindrical pressure hull has a diameter of 4400mm (14.42') and is made of 18mm (.73") steel with inside bulb tee frames 200X11 (7.88" web depth X .43" web thickness) on 700mm (27.56") centers. The plating is gradually reduced throughout the tapered sections fore and aft to 16mm (.63"), and the frames are correspondingly reduced to 130X9 (5.12" X .35"). Frames spacing remains unchanges in the tapered sections.
The specification for the pressure hull plating and frames calls for a tensile strength of 74000 psi with a yeild point of 513000 psi. The steel is known as No. 52; the specification for plates is KM 9104, and for frames is KM 9103.
Framing is modified in the way of the main motors, to provide clearance, by substuting double frames 160X9 (6.30"X.35") for normal 200X11 frames.
In addition to the dished end bulkheads of cast steel, four other dished cast bulkhead are fitted, dividing the pressure hull into five pressure compartment. These bulkhead are 22mm thick; but material specifications, while inknown, are believed to be German cast steel 45.81 per KM 9106.
Further subdivision is provide 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 desinged for pressure differential of 3 psi only, but in practice serve no pressure purpose because they have so many non-tight openings.
Large openings in the pressure hull consist of the two torpedo hatches, one galley hatch, one engine room hatch, and 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.
Compersation for these openings is obtained in a number of different ways:
(a) 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"). 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.
(b) The galley and engine room hatches have no compensation other than their trunks, which are tubes with 20mm (.79) walls.
I have to go for now, will write more later
Scott
