Anyway, I’d heard something somewhere about such a conversion actually being considered so I went looking. Found the data in Friedman’s excellent US Cruisers – a Design History. There is a rough sketch on page 82 (back-of-a-napkin level) and descriptive data on pages 341-342. Also some data from the web.
Basically, the US had considered converting the Omaha class to CLAA following British success with the C class conversions. This was mid-1940. The initial design (and the one that matches the sketch) called for removal of all of the casemated 6inch guns, the 3inch guns, and the torpedo tubes. An AA Battery of 5inch/25 and quadruple 1.1inch guns was to be added. 5inch/38 were preferred but were in short supply. BuOrd reported that twenty-one 5inch/38 and twenty-four 5inch/25 would be available “in the near future”. This would be enough for three ships with 5inch/38 and three with 5inch/25. The multiple 1.1inch guns would not be available in sufficient quantity. Retention of some (probably four) 3inch guns would be a short term alternative.
The design related to the sketch called for trunking the four funnels into two. Number two was trunked forward to number one and number three trunked backward to number four. Trunking was above deck. Between these two sets of trunking was a new centerline deckhouse with two 5inch guns mounted on it. Quadruple 1.1inch mounts were placed port and starboard abreast of the two remaining funnels. Ship’s boats were to be stored outboard of the deckhouse (both sides) and forward of number one funnel . The forward casemated guns were to be replaced by a platform that superfired the forward 6inch turret. This would mount two 5inch guns (port and starboard) and a single quad 1.1inch forward of them and on the centerline. Aircraft and catapult(s) were retained and mounted abaft the number four funnel. [s]Neither sketch nor narrative reveals whether a single centerline catapult or two outboard catapults was/were intended.[/s] Yes it does, right there in the sketch. Two catapults, outboard. Left it out of my notes and then forgot about it! Aft of the catapults the torpedo tubes, aft casemated guns and all existing AA guns were removed and replaced with a concentration of three 5inch guns and one more quadruple 1.1inch mount. The most forward of the 5inch guns were mounted port and starboard with the third aft of them and on the centerline. Then the 1.1inch mount, directly before and superfiring over the aft 6inch turret. No mention is made of lighter AA but little marks on the design may represent individual weapons in the bridge wings. Probably 50-Calibre Machine Guns, three on each side I’d guess.
This would have given a total armament of:
Four 6inch guns in twin turrets fore and aft (original armament)
Seven single 5inch guns mounted two forward, two centerline amidships, and three aft.
Six quad 1.1inch mounted one forward, two each port/starboard, and one aft
Six single 50Cal MG mounted three each side (a guess!).
All other details would be the same – no change to armor or machinery.
Based on this I have come up with the following icon. I have no skill for making new icons but was able to alter the existing Omaha icon. Didn’t come out too badly I think. Game icons in the next post.
Following this design, there were several proposals for modification. Generally increasing numbers of 5inch at the expense of the hard-to-get 1.1inch, and rearranging the armament. A major issue was the lack of suitable directors, much less space to mount them. Another issue was the retention of the 6inch turrets, which were cramped and suffered from a low rate of fire. Sufficient ammo storage for large quantities of AA ammo was not available, even considering the magazines and handling areas freed up by removed of the casemated guns, original AA armament, and torpedo tubes. An even greater problem was berthing and messing space for the increased crews to serve and support the weapons. A plan to utilize extra engine room and supply department personnel for ammunition handlers was drawn up.
In any event the value of the converted cruiser was in doubt. The British got good value for the converted C class as their fleet was more deficient in AA capability. War Plans division pointed out that modern US DDs had dual purpose main batteries and the need for such marginal conversions was not as great.
Finally, in July 1940, the General Board ordered the replacement of two 3inch guns by quadruple 1.1inch mounts and for the conversion to CLAA when (and if) sufficient 5inch/25 and modern directors would become available.
Historically the conversions were never done, but there is sufficient design data to consider them in AE. If done, I would recommend a conversion from the first (December 1941) Omaha class. Only the first one, so once the 4/42 upgrade is done the ability to convert slips away. This reasonably represents the very-early possibility of such a conversion, especially during repair of a battle damaged ship.
