Part of the fun of a sim is being engrossed in a deep and rich world that feels as close to the real one as possible. Not only does the sim have to behave like the real thing, it has to look like it to; atmosphere matters.
Because I’ve always been fascinated with the construction of the U-Boats, and I need to make a super accurate model for the sim, I am building a scene where the user will get to see the U-Boat they will command being build, piece by piece. Using archived materials, I am building a model I can use for this. Here is the work in progress so far:
Some of my reference material
Some reference info from the VIIC Manual
General construction of U-boats.
Type VIIC U-boats are medium sized mixed construction boats. The boat is built from following parts:
- pressure hull with conning tower
- outer shell
- upper deck and bridge deck
The conning tower, which is located above the control room at half of the pressure hull length is connected to it by means of the control room hatch. The outer shell encloses the stern, both sides and the bow of the pressure hull. The substructure of the upper deck extends over the full length of the boat and is welded to the pressure hull by means of knee-plates. To reduce the drag while submerged, the conning tower is enclosed by the conning tower casing. In the bottom of the pressure hull there is a 0.5 meter high and 1.1 meter wide keel box.
Construction of the pressure hull.
The pressure hull has a circular cross-section over its full length. The hull consists of one cylindrical and seven cone-shaped parts. These parts are joined together by arc welding, and strengthened from inside by 82 frames – which are made from bulb tee girders – and pressure-proof and watertight bulkheads. The quality of the arc welds are tested by the shipyard with radiographics. At first 25% of all welded joints on type VII boats were faulty, due to strict testing this number reached 15%. This ensures greater resistance to water pressure at deep depths. The thickness of the pressure hull plates decreases towards the ends.
Especially stressed areas (i.e. under the conning tower and around the aft torpedo hatch, exhaust valves and diesel engine room patch) are further strengthened with thicker plates. Both ends of the pressure hull are enclosed by two outside cambered dished plates. The forward end of the pressure hull is adequately strengthened to account for the weakening due to the openings for the four torpedo tubes. The thickness of plating in the cylindrical part of the hull is 18.5 mm and decreases towards the forward and aft ends and in conical parts is 16 mm. The thickness of plating at both hull endings is 35 mm.
Partitioning of the pressure hull.
The pressure hull is divided into three compartments by two pressure-proof bulkheads and subdivided into six rooms by the following watertight bulkheads, which from aft are as follows:
Compartment I (Frame 0-39)
Room 1: Aft torpedo- and E motor room Frame 0 – 16-1/2. 1 stern torpedo tube, E motors, converters, switchboards, air compressors, driving motors for main rudders and after dive planes, torpedo compensating tank and after trim tank, 1 oxygen flask, 1 emergency fresh water tank. Under floor: stowage for 1 reserve torpedo, stowage for 3 distilled water containers.
Room 2: Diesel engine room Frame 16-1/2 – 29. Diesel engines and auxiliary machinery, 2 starting air flasks, 2 oxygen flasks. Under floor: lubricating oil supply tanks, lubricating oil collecting tanks, dirty oil tank, fuel oil collecting tanks.
Room 3: Petty officers room Frame 29 – 39. W.C., galley, stowage for provisions, automatic battery switch 1, refrigeration plant, HP air bank 3. Under floor: fresh water tank 1, waste water tank 1, fuel oil tank 1, battery room 1.
Compartment II (Frame 39 – 50-1/2)
Room 4: Control room. Main drain pump, auxiliary drain and trim pump, drive for aft (attack) periscope, control station for main rudder and dive planes, gyro compass, refrigeration plant, distilling unit, trimming station, fresh water tank 2, 4 oxygen flasks. Under floor: main ballast tank 3 (Frame 41 – 48).
Compartment III (Frame 50-1/2 – 80)
Room 5: Officers- and chief petty officers quarters Frame 50-1/2 – 60, radio- and underwater telegraphy room, listening room, automatic battery switch 2, stowage for provisions, W.C., fresh water tank 3. Under floor: fuel oil tank 2 (Frame 48 – 63), storage for explosive charges, munitions magazine, active sonar room, wash water tank, waste water tank 2, battery room 2.
Room 6: Forward torpedo room Frame 63 – 80. 4 bow torpedo tubes, auxiliary stowage for 2 reserve torpedoes, HP air pressure bank 4 and 5, 3 oxygen flasks. Under floor: stowage for 4 reserve torpedoes or mines, torpedo compensation tanks 2 and 3, forward trim tank. 4) Conning tower structure. The shape of the conning tower in horizontal cross-section is an ellipse in the aft section and the arc of a circle in the lateral and forward sections. These parts are joined together without flat spots. The radius of the forward arc is 575 mm, and that of the side arcs 2260 mm. To decrease the drag of the conning tower during submerged cruise, the tower is enclosed with a casing. The conning tower is enclosed at the top by the bridge deck fabricated from 30 mm thick steel plate, which is welded to the conning tower walls. The thickness of the conning tower wall plates is 32 mm. In conning tower are installed: aft (attack) periscope with hydraulic driving motor, main rudder steering station, torpedo fire control installation.
5) Openings in the pressure hull. The opening in the pressure hull are necessary for:
- Linkage and shafts
- Hull fittings
- Communication equipment
Measuring equipment. All installations passing through the hull are tested at 15 at.