This building contract can be found on the Deutsche Digitale Bibliothek. As usual no details of cemented armor are given (in that it was delivered to the shipyard) and there are no plans. However, there are a number of plans at BAMA Freiburg. It may well be that none of these correspond exactly to the ship described in the building contract. Unlike the contract for Ersatz Gneisenau (1914), there are no penalty clauses in this 260 page document. Of course, in this case the shipyard did not make the boilers and machinery with the diesel engines being delivered to it, so the shipyard would not have been responsible for the ship making its design speed or for the fuel consumption of the engines.
The contract does not appear to give the hull length or beam and, in fact, none of the plans I found listed the beam either. The hull depth amidships was 15.550 m, with the upper deck rising to 19.120 m above the keel at the bows and 15.920 m at the stern. The upper deck camber resulted in the upper deck amidships at the centreline being 370 mm above the 15.550 m figure at the sides. The battery deck was 13.25 m above the keel amidships and the armor deck 11 m above. The Zwischendeck was a little below the flat part of the armor deck unlike in Bismarck where it was a little above the flat part of the armor deck. This may have been because the separation of the armor and battery decks was only 2.25 m in the H class. The double bottom was in general 2 m deep within the citadel The total depth of the armor belts amidships was 7.375 m, of which the main belt accounted for 5.175 m. The bottom edge of the main belt was located 8.175 m above the top edge of the outer double bottom and the taper at the bottom started at 9.525 m above the keel. The top edge of the main belt was 100 mm above the battery deck, which was located 11 m above the keel. However, the plans given in RM 25/15824 at Freiburg of the ship dated 1940 show the taper to be at the top of the belt and not the bottom. The plans for 1938 given in RM 25/7375 show a ship with the taper at the bottom. The hull plating behind the lower half of the main belt was 16 mm thick and that behind the upper half 18 mm as in Bismarck. The plating behind the upper belt was to have been 26 mm thick Wh n/A. The stern belt ran from frame 10 to frame 43 and the bow belt from frame 213 forwards to the bow. The thicker part of the bow belt, covering the torpedo room ran between frames 213 and 234. The hull above the aft belt was 35 mm Wh except right aft. Forward the hull was 35 mm thick Wh above the fore belt up to the battery deck and 20 mm thick Wh above that except right forward.
The main armor deck was 110 mm thick aft of frame 43 and uniformly 100 mm on the flat and 120 mm on the slope in the citadel. However, throughout the citadel there was a doubler plate 30 mm thick and 1500 mm wide at the top of the slope. So here the sloped deck was 150 mm thick. The lower end of the sloped deck reached the belt 8.619 m above the top of the outer keel. The upper platform deck was 50 mm thick over the torpedo room and 30 mm thick forward of that. The upper deck was 50 mm thick between frames 28.5 and 226.5, except around the aft four 5.9 in turrets. In this region there were 60 mm plates outwards from the outer splinter bulkhead, thickening to 70 mm before reaching 80 mm thick at the outer edge. This thickening was to compensate for loss of hull strength due to the openings in the upper deck for the barbettes and the discontinuity in the outer splinter bulkhead. Between frames 10.5 and 28.5 and between frames 226.5 and 249 the upper deck was 35 mm thick, except directly over the middle rudder and side rudder machinery rooms where it was 50 mm. The plan for the ship in 1938 in RM 25/7375 gives a SPS width of 6.0 m.
The torpedo bulkheads were 45 mm thick from the keel up to about 500 mm above the armor deck. The lower edge of the torpedo bulkhead was rivetted to the hull bottom. There were no specific stiffeners for this bulkhead. Stiffening was effected by the platform decks, the outer longitudinal bulkhead in combination with what was termed the outer platform deck (the division in the bunkers) and the double bottom. The plan in RM25/15824 for the ship in 1940 shows that the TB was amidships 13.1 m out from the centreline. The three secondary sources I have give the beam as variously 37 m, 37.2 m and 37.6 m. Taking the 37 m figure the SPS width would have been 5.4 m. Taking this and the other dimensions, and making allowance for the belt thickness, wood backing and hull skin thicknesses, the slope of the armor deck amidships would have been about 25.3 deg to the horizonal.
The TB bulkhead was continued upwards as a 25 mm thick splinter bulkhead. Between turrets B and D there were a second pair of longitudinal splinter bulkheads, located 4.4 m outboard of the centreline amidships. There were also five transverse 20 mm thick splinter bulkheads within the citadel. The CT was larger than in previous ships. The more heavily protected upper level contained in the forward part the ship command centre and the aft part the artillery control position. The forward part of the lower level contained the chart house and the after part the intelligence centre. The structure of the CT substructure was also more complex with an (apparently) 150 mm protected inner part and a 60 mm thick outer layer.
The main turrets and their rotating substructure weighed 1454 mt. The guns could elevate between +33 and -5.5 deg and it was specified that all stages of their ammunition supply were to be capable of maintaining a rate of fire of 2.5 rounds per gun per minute. The forward pair of 5.9 in turrets weighed about 122 mt and the others weighed 120 mt. These weights were very similar to those of Scharnhorst and higher than the figures in Bismarck. The 4.1 in turrets were given as about 45 mt each, much higher than in earlier ships.
Overall, the H class had a citadel shorter in relation to the size of the ship than in earlier ships and H also had a rather higher armor deck (at 0.707 of hull depth compared with 0.687 in Bismarck). This latter feature may have resulted from diesel engines being higher than boilers/turbines, but they were also somewhat shorter, which meant citadel length did not increase, despite more space being needed for magazines. This rather higher armor deck somewhat reduced hull volume above the armor deck despite an increased hull depth, while increasing the volume below the armor deck. The resulting slightly lower shelter of the armor deck by the main belt might have been the reason for the reinforcement plating to the top part of the sloped deck, especially if the taper of the belt was at the top. If a shift in the belt taper from bottom to top was made after the contract was issued, this might have shown the Germans were becoming more concerned about underwater hits even before the Battle of the Denmark Strait. Splinter protection above the armor deck was considerably increased. Overall, it might be argued that the protective characteristics of the H class moved a little towards the international norm but within the constraints of, and having the advantages of, the traditional German system. Possibly constraints on beam led to the higher L/B ratio and a slightly higher prismatic coefficient than in Bismarck,
Neil Robertson
The contract does not appear to give the hull length or beam and, in fact, none of the plans I found listed the beam either. The hull depth amidships was 15.550 m, with the upper deck rising to 19.120 m above the keel at the bows and 15.920 m at the stern. The upper deck camber resulted in the upper deck amidships at the centreline being 370 mm above the 15.550 m figure at the sides. The battery deck was 13.25 m above the keel amidships and the armor deck 11 m above. The Zwischendeck was a little below the flat part of the armor deck unlike in Bismarck where it was a little above the flat part of the armor deck. This may have been because the separation of the armor and battery decks was only 2.25 m in the H class. The double bottom was in general 2 m deep within the citadel The total depth of the armor belts amidships was 7.375 m, of which the main belt accounted for 5.175 m. The bottom edge of the main belt was located 8.175 m above the top edge of the outer double bottom and the taper at the bottom started at 9.525 m above the keel. The top edge of the main belt was 100 mm above the battery deck, which was located 11 m above the keel. However, the plans given in RM 25/15824 at Freiburg of the ship dated 1940 show the taper to be at the top of the belt and not the bottom. The plans for 1938 given in RM 25/7375 show a ship with the taper at the bottom. The hull plating behind the lower half of the main belt was 16 mm thick and that behind the upper half 18 mm as in Bismarck. The plating behind the upper belt was to have been 26 mm thick Wh n/A. The stern belt ran from frame 10 to frame 43 and the bow belt from frame 213 forwards to the bow. The thicker part of the bow belt, covering the torpedo room ran between frames 213 and 234. The hull above the aft belt was 35 mm Wh except right aft. Forward the hull was 35 mm thick Wh above the fore belt up to the battery deck and 20 mm thick Wh above that except right forward.
The main armor deck was 110 mm thick aft of frame 43 and uniformly 100 mm on the flat and 120 mm on the slope in the citadel. However, throughout the citadel there was a doubler plate 30 mm thick and 1500 mm wide at the top of the slope. So here the sloped deck was 150 mm thick. The lower end of the sloped deck reached the belt 8.619 m above the top of the outer keel. The upper platform deck was 50 mm thick over the torpedo room and 30 mm thick forward of that. The upper deck was 50 mm thick between frames 28.5 and 226.5, except around the aft four 5.9 in turrets. In this region there were 60 mm plates outwards from the outer splinter bulkhead, thickening to 70 mm before reaching 80 mm thick at the outer edge. This thickening was to compensate for loss of hull strength due to the openings in the upper deck for the barbettes and the discontinuity in the outer splinter bulkhead. Between frames 10.5 and 28.5 and between frames 226.5 and 249 the upper deck was 35 mm thick, except directly over the middle rudder and side rudder machinery rooms where it was 50 mm. The plan for the ship in 1938 in RM 25/7375 gives a SPS width of 6.0 m.
The torpedo bulkheads were 45 mm thick from the keel up to about 500 mm above the armor deck. The lower edge of the torpedo bulkhead was rivetted to the hull bottom. There were no specific stiffeners for this bulkhead. Stiffening was effected by the platform decks, the outer longitudinal bulkhead in combination with what was termed the outer platform deck (the division in the bunkers) and the double bottom. The plan in RM25/15824 for the ship in 1940 shows that the TB was amidships 13.1 m out from the centreline. The three secondary sources I have give the beam as variously 37 m, 37.2 m and 37.6 m. Taking the 37 m figure the SPS width would have been 5.4 m. Taking this and the other dimensions, and making allowance for the belt thickness, wood backing and hull skin thicknesses, the slope of the armor deck amidships would have been about 25.3 deg to the horizonal.
The TB bulkhead was continued upwards as a 25 mm thick splinter bulkhead. Between turrets B and D there were a second pair of longitudinal splinter bulkheads, located 4.4 m outboard of the centreline amidships. There were also five transverse 20 mm thick splinter bulkheads within the citadel. The CT was larger than in previous ships. The more heavily protected upper level contained in the forward part the ship command centre and the aft part the artillery control position. The forward part of the lower level contained the chart house and the after part the intelligence centre. The structure of the CT substructure was also more complex with an (apparently) 150 mm protected inner part and a 60 mm thick outer layer.
The main turrets and their rotating substructure weighed 1454 mt. The guns could elevate between +33 and -5.5 deg and it was specified that all stages of their ammunition supply were to be capable of maintaining a rate of fire of 2.5 rounds per gun per minute. The forward pair of 5.9 in turrets weighed about 122 mt and the others weighed 120 mt. These weights were very similar to those of Scharnhorst and higher than the figures in Bismarck. The 4.1 in turrets were given as about 45 mt each, much higher than in earlier ships.
Overall, the H class had a citadel shorter in relation to the size of the ship than in earlier ships and H also had a rather higher armor deck (at 0.707 of hull depth compared with 0.687 in Bismarck). This latter feature may have resulted from diesel engines being higher than boilers/turbines, but they were also somewhat shorter, which meant citadel length did not increase, despite more space being needed for magazines. This rather higher armor deck somewhat reduced hull volume above the armor deck despite an increased hull depth, while increasing the volume below the armor deck. The resulting slightly lower shelter of the armor deck by the main belt might have been the reason for the reinforcement plating to the top part of the sloped deck, especially if the taper of the belt was at the top. If a shift in the belt taper from bottom to top was made after the contract was issued, this might have shown the Germans were becoming more concerned about underwater hits even before the Battle of the Denmark Strait. Splinter protection above the armor deck was considerably increased. Overall, it might be argued that the protective characteristics of the H class moved a little towards the international norm but within the constraints of, and having the advantages of, the traditional German system. Possibly constraints on beam led to the higher L/B ratio and a slightly higher prismatic coefficient than in Bismarck,
Neil Robertson
statistics: Posted by neilrobertson1 — 11:50 AM - 1 day ago — Replies 1 — Views 177