USS Ranger (CV-4) (1933)
USS Ranger (CV-4) was the first USN aircraft carrier designed as such, and remained unique. She was a relatively light Treaty ship, with a displacement of only 15,000 long tons (15,000 t), and an island superstructure which was added after completion. Her small size and low speed eliminated her from the Pacific Fleet and instead spent most of the war in the Atlantic, providing air support for Operation Torch, and Operation Leader off Norway among others. She was too small to deploy an efficient air group, which was taken in account for the Yorktown class.
Design work started already in 1925. By then, conversion work was still ongoing on the Lexington class carriers, and a fourth carrier was needed the Navy. Until the, the only aircraft carrier in service was by then the slow and small USS Langley, a converted collier. The Lexington and Saratoga were also converted from, but based on battlecruisers, making the best of their size and speed. The hypothetical fourth Carrier was seen as an opportunity to create a carrier from scratch. Preliminary design work was mostly theoretical, as only the Langley was in service, and at best a stopgap solution, whereas the most promising Lexington could not bring any lessons, as they were far from completion (in 1927). With this limited experience to draw on, characteristics were defined after reports from wargaming experience, at the U.S. Naval War College. The initial design was ready in 1927, but any alterations would follow as a result of the recent experiences in the Lexington and Saratoga
USS Ranger, Lexington and Saratoga
The Washington treaty CV's displacement limits
There was however, a major limitation to the admiralty's ambitions for the new vessel, in size and speed: The constraints of the Washington Naval Treaty signed in 1920. The Lexingtons displaced 69,000 long tons and ate a considerable part of the allowed tonnage for this category. This left room for three 23,000 long ton carriers, four 17,250 ton carriers, and five 13,800 ton carriers, as calculated; The smaller one, at 13,800 was selected first to rapidly ramp-up the USN aircraft carrier force. Wargames shown severe attrition to airframes and hulls and the college preconized to cram as many aircraft on the hulls allowed. One of the key feature of the design was the fact the hull was flush-decked to simplify the structure and the flying deck ended without overhanging the prow and stern. This flight deck was designed clear of obstacles, but this complicated the machinery arrangements.
Ranger's prow in drydock, 1937
The problem of smoke
To get rid of the smoke the solution was to truncate exhausts from the six boilers into a corresponding number of small stacks, three either side of the aft hangar, hinged and rotated parallel with the hangar deck. This setup was only used for flight operations. They were back to vertical when speeding up. By that point the carrier was "headless", with any island, and when added, the uptakes were not moved into the island as a cost-saving measure. Smoke dispersion was a great deal indeed, the source of major interference for air operations, impacting in turn the propulsion design. The powerplant management reflected this, by an optimal placement of the boilers which was supposed to decrease the the amount of smoke generation. A relatively modest 53,000shp powerplant was chosen, small enough to be placed further aft, compared to a much larger power unit. But it left little room for improvement on the ship, without compromising top speed. These boilers had their stacks places so to disperse smoke over less deck surface, and in lower quantity, and still due to space issues, more compact geared turbines were installed.
Original blueprint extract, island superstructure. Src
The Tour de Force: 76 aircraft on a small package
The upper deck was entirely cover by the hangar, without space loss. The high open girders of the flight deck structure made for a roomy space for plane storage. The hangar deck was semi-open however, with large roll-up metal curtain doors, open in summer or in tropical waters, and closed in bad weather. This was followed by the installation of two catapults on the hangar deck to launch of observation aircraft, later dropped as cost saving measure. There was also a gallery deck between the flight deck and hangar deck. The latter was a light superstructure (for stability), sheathed in wood (for heat). It was found to be easy to maintain and repair but offered no protection. To serve the deck, three elevators were installed (the forward one, at the end of the flying deck, was later removed, leaving only the two large lifts amidship, offset to the right. Outriggers at the edge of the flight deck provided more space to stack aircraft on the deck, which was a novel feature. Between this long deck and roomy hangar, engineers managed to create enough stowage for up to 76 aircraft, equal to the much larger and costier Lexington class
, and with just half the displacement. That was probably there that reside the main tour de force
of the design.
The onboard armament was also innovative: Rather than to stack heavy guns for self-defense, aviation was trusted enough to limit it to lighter dual purpose guns. Eight dual-purpose 5-inch (127 mm)/25 caliber guns, the same caried by cruisers of the time, were installed, in sponsons platforms fore and aft, and controlled by two Mark 33 directors. Dive-bombing attacks were feared, and so this was initially complemented by forty .50 cal machine guns placed along the gallery. This armament after Pearl Harbor proved inadequate and in 1942, it was completely modernized with the usual 20 mm Oerlikon guns.
Launch of USS Ranger at Newport News, February 24, 1933
As finalized, the initial design was submitted to bidders, authorized by the Congress on 13 February 1929. Bids for the construction were opened by the Navy on 3 September 1930. After the selection, Newport News Shipbuilding won over Bethlehem Shipbuilding Corp. and New York Shipbuilding Co. which answered the call in time with proposals. In November 1929, Newport News Shipbuilding officially signed the contract, which price was 15.2 million dollars. On 10 December, the new carrier was named, as USS Ranger. This was an old name, already used by John Paul Jones's sloop of war in 1777. The famous US Rangers inspired this name, they were a well-trained militia witch served in the 17th and 18th-century "Indian and French war" notably between American colonists and Native American tribes. The name was resurrected in WW2 for US Commandos.
Appearance in 1942 - Blueprint sold on EBay
As blueprints goes, the USS Ranger was to be 14,700 tonnes, and after completion, she displaced 14,576 long tons (14,810 t) standard and 17,577 long tons (17,859 t) fully loaded. She measured 730 ft (222.5 m) at the waterline and 769 ft (234.4 m) overall, for a 80 ft (24.4 m) beam at the waterline and 109 ft 5 in (33.4 m) overall at the level of the deck gallery. Her draft was of 22 ft 4.875 in (6.8 m).
The USS Ranger was given two shafts, driven by two geared steam turbines, fed by six boilers, for a total output of 53,500 shp (39,900 kW) and a top speed of 29.3 knots (54.3 km/h; 33.7 mph). Her range was 10,000 nautical miles (19,000 km; 12,000 mi) at 15 knots (28 km/h; 17 mph).
It was limited to a 2 in (5.1 cm) thick belt with some ASW compartmentation behind but no longitudinal bulkhead, transverse bulkheads of 2 in (5.1 cm) too, and a partial armour deck stray of 1 in (2.5 cm) over the steering gear. The gasoline tanks or ammunition stores were not protected.
Initially, she carried eight 5 in (127 mm)/25 cal anti-aircraft guns and 40 × .50 in (12.7 mm) machine guns in single overhanging positions along the decks, starboard and port. This armament was maintained until March 1942, but before that, a battery of 3-inch (76 mm)/50 caliber guns were installed, replaced later by 1.1-in quadruple mounts (40 mm). It was again modified in 1943 during the carrier's major refit.
Great Lakes dive bombers in formation
Certainly the most important part: Although on paper 76 was the normal provision, up to 86 could be carried, some suspended under the roof and partly dismounted, and the deck full. It was hardly practical for operations. In practice, about 65 planes was consider ideal. In any case, it diminished rapidly as planes grew larger. When USS Ranger was commissioned on 4 June 1934, she was given no torpedo stowage and no torpedo bomber squadron as a cost saving measure. USS Wasp matched this. It was not before 17 October 1941 that this issue was solved by authorizing a proper torpedo stowage during an overhaul and first torpedo squadron, equipped with the Douglas TBD devastator
. On 10 January 1942 the torpedo Squadron 4 (VT-4) was activated.
As commissioned, USS Ranger carried the Curtiss BF2C-1 Goshawk
fighter with the VB-5, replaced soon after by the Grumman FF
. In complete USS Ranger carried the Great Lakes BG
dive bomber and SOC Seagull for observation.
USS Ranger could have evaluated also the Curtiss F7C Seahawk, Northrop BT, and Vought SBU Corsair. From 1937, her fighters were replaced by the Grumman F3F
and in 1938, the Vought SB2U Devastator replaced the Great Lakes BG. Of course it would evolved again in 1941, with the arrival of the first TB group of VT-4 equipped with the TBD Devastator while Grumann Wildcat fighters replaced earlier F3F biplanes.
SB2U-1 of Air Group Commander USS Ranger 1940
SB2U-3 of VS41 onboard USS Ranger, 1941
SB2U-2 of VS42 onboard USS Ranger, 1941
Douglas TBD Devastator
Grumman F3F-1 of VF-4 on board USS Ranger, 1940
Grumman F4F3A of the VF41 on USS Ranger in early 1942. USS Ranger was the first USN carrier to receive the new fighter of the USN.
Newport News Shipbuilding in Virginia received 15.2 million dollars for the Ranger as part of the contract, and she was laid down on 26 September 1931, and launched on 25 February 1933. That day, she was sponsored by Lou Henry Hoover, First Lady of the United States. The island was only added during completion, and it added to the ship's displacement, now up to 14,500 tons. She started her early machinery trials on 1 May 1934, making 30.35 knots over an output of 58,700 shp. She was eventually commissioned at the Norfolk Navy Yard on 4 June 1934. Her first Captain was Arthur L. Bristol.
USS Ranger initially had an incomplete air group, missing the torpedo bombers and even installations and stowage of aerial torpedoes. USS Wasp compensated by its air group.From 17 October 1941 however, torpedo stowage was installed during the overhaul, but the vessel had to wait until 10 January 1942 for its first Torpedo Squadron VT-4 to be constituted. In 1941 also, Ranger's 5-in gun were added. In 1942, six 1.1-in quad mounts were installed but replaced by 3-in (76 mm)/50 guns is placeholders. From March 1942, the .50 cal machine guns were deposed an all replaced by Oerlikon 20mm cannons (46 20mm mounts) while the 1.1-in battery was replaced by six quadruple Bofors 40mm guns in December 1942, two placed fore and aft of the island, two on the sides, and one at the stern and another at the prow.
On 13 December 1943, the Chief of Naval Operations Admiral Ernest King had approved an extensive modernization of the Ranger. Size of carrier aircraft indeed became massive, and the tiny and narrow flight deck or the Ranger, at the time fit for the small and light biplanes of the time, was were no relevant for a modern air group. Here is the list of modifications made:
-Aft elevator enlarged, amidship elevator replaced with a deck-edge elevator
-Two flight deck catapults installed.
-Hull blistered to increase stability and ASW protection.
-Armament increased with six 40 mm quadruple mounts, including two fitted for and aft of the island.
-Additional 20 mm Oerlikon AA guns
-New radar and modernized electronics
Admiral King however met but the string resistance of the Bureau of Ships, which insisted that manpower and resources would delay the precious completion of more capable Essex-class aircraft carriers ten under construction. The project was postpone indefinitely by 5 April 1944 after after a third estimate. However it was eventually approved and Ranger was in York Harbor on 16 May 1944, Norfolk Navy Yard for a partial application of the plan: She had her flight deck strengthened, the catapults installed and updated radar, notably to enable night fighter-interceptor training capabilities.
HD photo of the Ranger at anchor in 8 April 1938.
Specifications as completed
|Dimensions||730 ft (222.5 m) wl, 769 ft (234.4 m) oa x 80 ft (24.4 m) wl, 109 ft 5 in (33.4 m) oa x 22 ft 4.875 in (6.8 m)|
|Displacement||14,576 long tons standard, 17,577 long tons fully loaded|
|Propulsion||2 shafts steam turbines, 6 × boilers 53,500 shp (39,900 kW)|
|Speed||29.3 knots (54.3 km/h; 33.7 mph)|
|Range||10,000 nmi (19,000 km; 12,000 mi) at 15 knots (28 km/h; 17 mph)|
|Armament||8 × 5 in (127 mm)/25, 40 × .50 M2HB in HMG, CXAM-1 radar|
|Armament (1944)||8 × 5 in (127 mm)/25, 6x4 40 mm AA, 40 x 20mm AA, updated radar, 60 planes|
|Aviation||86 (maximum), 76 (normal), 3 elevators, 3 catapults after refit|
|Armor||Belt 2 in (5.1 cm), Bulkheads: 2 in (5.1 cm), Deck: 1 in (2.5 cm) over steering gear|