Technology and Operations
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Re: Pressure hull construction - VIIC boats
Posted by:
Scott
()
Date: November 12, 2002 10:08PM
The Superstructure
The superstrucute consists of a light frame structure of angles, with a strake of plating riveted along the sides, and plating sections secured by machine screws on the deck in the way of the two capstens and the 10 topside torpedo stowage tanks. The remainder of the deck is of wood slatting. Note here that the two forward torpedo stowage tanks on the starboard side have been removed in those vessels equipped with snorkels.
The superstructure encloses, as well, the ballast tank vent piping and valves, the induction and exhaust air ducts, the mufflers, work boat and the usual other stowages. It also provides foundations for bitts and fairleads.
Extending above the superstructure is the conning tower fairwater and bridge strcuture, projecting from the front of which, at the base, is the non-magnetic (aluminum-manganese 5.25 per specification KM Norm 9304) housing for the magnetic compass. As originally designed, the structure extended aft of the conning tower far enough to provide a housing for the outboard ventilation valves, and provided a bridge platform with room for one 20mm gun. As redesigned, the structure was widened and aised aft of the bridge proper,to provide space for two 37mm guns, and was extended aft at a lower level to provide room for a 40mm gun. Splinter protection was added at the same time.
The fairwater and bridge bulwark plating is 3mm (.12") and the bulwark is further provided with 14mm (.55") splinter proection. Steel 42 (60000 psi tensile) is used for plating and framing except for:
(a) Splinter protection, which is probably the special steel known to the Germans as Wsho/Mo.
(b) Plating and framing within 900mm (35.4") of the magnetic compass, which is of aluminum-magensium 5.25 per specification KM 9304.
Riveting is employed throughout except for removable plates which are provided with screws.
The keel strucutre is a box section extending from the bottom of the pressure hull, and faired in to the pressure hull at both ends. It is made up of a central vertical keel of 8mm (.31") material and a heavy sole piece. Verical transverse stiffeners from the pressure hull to the sole piecie complete the strength members. The outboard faces of the box are closed by light plating secured with screws, and the space on both sides of the vertical center keel within the light side plating is used for the stowage of cast iron block ballast. Scantlings of the box keel are not available. Material is steel 42.
Aft of the end of the box keel, and extending aft as far as the rudder, a deadwood is built out below the pressure hull, which provides a housing for the stern planes actuating linkage and support for the stern planes, struts and rudder skeg. In section it approximately a V. Scantling are not available. Material is steel 42.
Internal Decks
Walking flats are in general very light. Further, no reinforcing is provided below hatches, so there is a permanent dent in the deck below each hatch. Substential decking is provided only the battery wells.
Castings
There is no stem casting. A casting is employed at the afer end of the deadwood and another casting extends below the deadwood to sever as a skeg and, when docking, as a means of supporting the after strucutre of the vessel. The struts are casting s the arms of which are riveted to the pressure hull and to the deadwood.
Will write more tomorrow.
Scott
The superstrucute consists of a light frame structure of angles, with a strake of plating riveted along the sides, and plating sections secured by machine screws on the deck in the way of the two capstens and the 10 topside torpedo stowage tanks. The remainder of the deck is of wood slatting. Note here that the two forward torpedo stowage tanks on the starboard side have been removed in those vessels equipped with snorkels.
The superstructure encloses, as well, the ballast tank vent piping and valves, the induction and exhaust air ducts, the mufflers, work boat and the usual other stowages. It also provides foundations for bitts and fairleads.
Extending above the superstructure is the conning tower fairwater and bridge strcuture, projecting from the front of which, at the base, is the non-magnetic (aluminum-manganese 5.25 per specification KM Norm 9304) housing for the magnetic compass. As originally designed, the structure extended aft of the conning tower far enough to provide a housing for the outboard ventilation valves, and provided a bridge platform with room for one 20mm gun. As redesigned, the structure was widened and aised aft of the bridge proper,to provide space for two 37mm guns, and was extended aft at a lower level to provide room for a 40mm gun. Splinter protection was added at the same time.
The fairwater and bridge bulwark plating is 3mm (.12") and the bulwark is further provided with 14mm (.55") splinter proection. Steel 42 (60000 psi tensile) is used for plating and framing except for:
(a) Splinter protection, which is probably the special steel known to the Germans as Wsho/Mo.
(b) Plating and framing within 900mm (35.4") of the magnetic compass, which is of aluminum-magensium 5.25 per specification KM 9304.
Riveting is employed throughout except for removable plates which are provided with screws.
The keel strucutre is a box section extending from the bottom of the pressure hull, and faired in to the pressure hull at both ends. It is made up of a central vertical keel of 8mm (.31") material and a heavy sole piece. Verical transverse stiffeners from the pressure hull to the sole piecie complete the strength members. The outboard faces of the box are closed by light plating secured with screws, and the space on both sides of the vertical center keel within the light side plating is used for the stowage of cast iron block ballast. Scantlings of the box keel are not available. Material is steel 42.
Aft of the end of the box keel, and extending aft as far as the rudder, a deadwood is built out below the pressure hull, which provides a housing for the stern planes actuating linkage and support for the stern planes, struts and rudder skeg. In section it approximately a V. Scantling are not available. Material is steel 42.
Internal Decks
Walking flats are in general very light. Further, no reinforcing is provided below hatches, so there is a permanent dent in the deck below each hatch. Substential decking is provided only the battery wells.
Castings
There is no stem casting. A casting is employed at the afer end of the deadwood and another casting extends below the deadwood to sever as a skeg and, when docking, as a means of supporting the after strucutre of the vessel. The struts are casting s the arms of which are riveted to the pressure hull and to the deadwood.
Will write more tomorrow.
Scott
