These plans are among those held at the Deutsche Digitale Bibliothek. O was termed here a battleship even though it was a type of battlecruiser. Plans for O were finalised in either July or September 1939 and these versions are probably those which secondary sources, such as Lenton, German Surface Warships of WW2 (1966), Breyer, Battleships and Battlecruisers 1905 - 1970 (1970) and Dulin and Garzke, Axis Battleships of WW2, give some details of. However, heavy ships building or planned in wartime often experienced considerable changes during the building period to reflect lessons learnt so far in the war. As usual, this building contract does not list some principal dimensions or belt armor thicknesses. There do not appear to be any penalties mentioned in the contract, which runs to about 260 pp.
The hull depth amidships at the side was 14.5 m, with the battery deck 11.9 m above the outer keel and the main armor deck was at 9.5 m. The double bottom was 2 m deep, the same as h and greater than the 1.7 m in earlier ships. The citadel/main belt extended from frame 37.5 to 191.5 so that the citadal was 154 m (505 ft) in length, very similar to Scharnhorst. The main belt had two strakes: the thicker one (backed by wood and therefore KC) extended from 305 mm above the armor deck (which was here flat) to 6.5 m above the inner keel (depth 3.305 m (10.8 ft) and tapered down from 6.8 m above the keel. The upper strake extended further up to about 100 mm above the battery deck (depth 2.195 m (7.2 ft). Above that the side was 30 mm thick. The fore belt was in one strake (depth not given) and extended forwards to the bow. The aft belt extended back to frame 9. Above the fore and aft belts the side was 20 mm thick. Within the CT there was a 30 mm thick bulkhead between the fore, ship command, part and the after, artillery command, part.
The torpedo bulkhead was 45 mm thick and rose from the outer bottom to the armor deck. It extended from frame 32.8 to frame 199 (166,2 m (545 ft) long. In the citadel it was vertical from armor deck to outer bottom but from Fr. 37.5 back and 191.5 forwards it was 'Knieblechartig' (shaped in the form of a (bent) knee) at its connection to the outer bottom. It was unusual in extending a bit out of the citadel at both ends. Between barbettes b and C there were longitudinal splinter bulkheads, 6 m from the centreline and rising from the armor deck to the upper deck, thickness 24 mm. There was also a longitudinal splinter bulkheads between barbettes A and B, 4.35 m from the centreline line and 24 mm thick. There were transverse splinter bulkheads between the armor deck and the upper deck at frames 37.5 and 191.5 and 25 mm thick. At frames 65.5, 95.5, 110.7 and 143.1 there were splinter bulkheads rising from the armor deck to the upper deck and between the ship's side and the longitudinal splinter bulkheads, which were 14 mm thick. Between the lower platform deck and the armor deck the frames at 39 and 190.5 were 30 mm thick. Outboard of the torpedo bulkhead the frame at 191.5 was 30 mm thick from the inner bottom to the armor deck. With the thicker transverse bulkhead inboard of the TB (thickness not given) at frame 191.5, the armored bulkhead at frame 190.5 was probably intended to stop any fragments that penetrated (see Axis Battleships by Dulin and Garzcke if you have a copy). The transverse bulkhead forward at frame 220 was 20 mm thick throughout from the bottom to the upper deck. The steering gear bulkhead at frame 9 was 80 mm thick from the bottom to about 90 mm above the armor deck.
The upper deck was 50 mm thick from bow to stern and was thus more extensive than in any other German or foreign ship. Earlier variants apparently had a 30 mm thick UD. Aft from frame 9 to frame 37 .5 the armor deck was 90 mm thick on the flat and 110 mm thick on the slopes. Over the citadel (from frame 37.5 to 191.5) the armor deck (here flat) was 60 mm thick apart from over the main magazines (from frame 37.5 to 67.5 and between frame 152 to 191.5) it was 90 mm thick, the latter figure being higher than in earlier design. The plates over the calculating stations should be large enough to allow the F/C computers (weighing about 1750 kg) to be lowered into them horizontally. This equipment was sensitive and was not on any account to be tipped. As far as I can see there was only one set of F/C computers (in the fore part of the citadel) but there was a reserve switching room and a reserve amplifying room, both aft. If so, this may have been justified by the lower number of guns than in other German heavy ships.
The main turrets were about 925 mt, this being 125 mt less than in the 38 cm turrets on Bismarck. AFAIK the turret armor in Bismarck was about 358 mt so the figure in O would have been something like 233 mt. Accordingly average turret plate thickness on O would have been about 65% that of Bismarck. As in H the ammunition supply in O was to have allowed a sustained rate of fire of the main armament of 2.5 rounds per gun per minute. The secondary turrets weighed 61.4 mt and the tertiary ones 46.5 mt. The latter figure was a little more than the 45 mt given for H in 1940, the mount having evidently grown in that time. The secondary barbettes were 20 mm thick and the tertiary 25 mm. These tertiary mounts had a rotating subturret structure. There was a transport way on the battery deck to allow exchange of ammunition between the main turrets and another one for exchange of ammunition between the secondary turrets. Shells could be hoisted outside the barbette structures up to and down from this transport way. There were to be two Flakvierling 20 mm on the tower bridge, a sign this was a 1941 design variant.
Compared with earlier design variants of O, evidently referred to in various secondary sources, this one had a thicker and more extensive UD and increases in armor deck thickness over the main magazines and the shafts and steering gear. Some weight compensation had evidently been made by limiting the height of the belt to just above the level of the battery deck as in Scharnhorst. It is not evident to me why the torpedo bulkheads extended fore and aft of the citadel. perhaps there was some more important equipment in the spaces so protected. The ship did have four partial transverse splinter bulkheads in the citadel following in part the example of H and the deeper, 2 m, double bottom. Apparently it also had three rudders but I did not notice these mentioned in this document. I also came across a plan elsewhere for O which showed the two outer shafts powered by turbines and the centre shaft by diesels. But it appears the later variants had this arrangement reversed, for diesels on the outer shafts and turbines on the centre,
Neil Robertson
The hull depth amidships at the side was 14.5 m, with the battery deck 11.9 m above the outer keel and the main armor deck was at 9.5 m. The double bottom was 2 m deep, the same as h and greater than the 1.7 m in earlier ships. The citadel/main belt extended from frame 37.5 to 191.5 so that the citadal was 154 m (505 ft) in length, very similar to Scharnhorst. The main belt had two strakes: the thicker one (backed by wood and therefore KC) extended from 305 mm above the armor deck (which was here flat) to 6.5 m above the inner keel (depth 3.305 m (10.8 ft) and tapered down from 6.8 m above the keel. The upper strake extended further up to about 100 mm above the battery deck (depth 2.195 m (7.2 ft). Above that the side was 30 mm thick. The fore belt was in one strake (depth not given) and extended forwards to the bow. The aft belt extended back to frame 9. Above the fore and aft belts the side was 20 mm thick. Within the CT there was a 30 mm thick bulkhead between the fore, ship command, part and the after, artillery command, part.
The torpedo bulkhead was 45 mm thick and rose from the outer bottom to the armor deck. It extended from frame 32.8 to frame 199 (166,2 m (545 ft) long. In the citadel it was vertical from armor deck to outer bottom but from Fr. 37.5 back and 191.5 forwards it was 'Knieblechartig' (shaped in the form of a (bent) knee) at its connection to the outer bottom. It was unusual in extending a bit out of the citadel at both ends. Between barbettes b and C there were longitudinal splinter bulkheads, 6 m from the centreline and rising from the armor deck to the upper deck, thickness 24 mm. There was also a longitudinal splinter bulkheads between barbettes A and B, 4.35 m from the centreline line and 24 mm thick. There were transverse splinter bulkheads between the armor deck and the upper deck at frames 37.5 and 191.5 and 25 mm thick. At frames 65.5, 95.5, 110.7 and 143.1 there were splinter bulkheads rising from the armor deck to the upper deck and between the ship's side and the longitudinal splinter bulkheads, which were 14 mm thick. Between the lower platform deck and the armor deck the frames at 39 and 190.5 were 30 mm thick. Outboard of the torpedo bulkhead the frame at 191.5 was 30 mm thick from the inner bottom to the armor deck. With the thicker transverse bulkhead inboard of the TB (thickness not given) at frame 191.5, the armored bulkhead at frame 190.5 was probably intended to stop any fragments that penetrated (see Axis Battleships by Dulin and Garzcke if you have a copy). The transverse bulkhead forward at frame 220 was 20 mm thick throughout from the bottom to the upper deck. The steering gear bulkhead at frame 9 was 80 mm thick from the bottom to about 90 mm above the armor deck.
The upper deck was 50 mm thick from bow to stern and was thus more extensive than in any other German or foreign ship. Earlier variants apparently had a 30 mm thick UD. Aft from frame 9 to frame 37 .5 the armor deck was 90 mm thick on the flat and 110 mm thick on the slopes. Over the citadel (from frame 37.5 to 191.5) the armor deck (here flat) was 60 mm thick apart from over the main magazines (from frame 37.5 to 67.5 and between frame 152 to 191.5) it was 90 mm thick, the latter figure being higher than in earlier design. The plates over the calculating stations should be large enough to allow the F/C computers (weighing about 1750 kg) to be lowered into them horizontally. This equipment was sensitive and was not on any account to be tipped. As far as I can see there was only one set of F/C computers (in the fore part of the citadel) but there was a reserve switching room and a reserve amplifying room, both aft. If so, this may have been justified by the lower number of guns than in other German heavy ships.
The main turrets were about 925 mt, this being 125 mt less than in the 38 cm turrets on Bismarck. AFAIK the turret armor in Bismarck was about 358 mt so the figure in O would have been something like 233 mt. Accordingly average turret plate thickness on O would have been about 65% that of Bismarck. As in H the ammunition supply in O was to have allowed a sustained rate of fire of the main armament of 2.5 rounds per gun per minute. The secondary turrets weighed 61.4 mt and the tertiary ones 46.5 mt. The latter figure was a little more than the 45 mt given for H in 1940, the mount having evidently grown in that time. The secondary barbettes were 20 mm thick and the tertiary 25 mm. These tertiary mounts had a rotating subturret structure. There was a transport way on the battery deck to allow exchange of ammunition between the main turrets and another one for exchange of ammunition between the secondary turrets. Shells could be hoisted outside the barbette structures up to and down from this transport way. There were to be two Flakvierling 20 mm on the tower bridge, a sign this was a 1941 design variant.
Compared with earlier design variants of O, evidently referred to in various secondary sources, this one had a thicker and more extensive UD and increases in armor deck thickness over the main magazines and the shafts and steering gear. Some weight compensation had evidently been made by limiting the height of the belt to just above the level of the battery deck as in Scharnhorst. It is not evident to me why the torpedo bulkheads extended fore and aft of the citadel. perhaps there was some more important equipment in the spaces so protected. The ship did have four partial transverse splinter bulkheads in the citadel following in part the example of H and the deeper, 2 m, double bottom. Apparently it also had three rudders but I did not notice these mentioned in this document. I also came across a plan elsewhere for O which showed the two outer shafts powered by turbines and the centre shaft by diesels. But it appears the later variants had this arrangement reversed, for diesels on the outer shafts and turbines on the centre,
Neil Robertson
statistics: Posted by neilrobertson1 — 12:27 PM - 1 day ago — Replies 0 — Views 95