The Curtiss SO3C Seamew/ Seagull was an unsuccessful attempt to replace the Curtiss SOC Seagull biplane spotter plane, and after a brief period of front line service in 1942-43 was withdrawn, and in some cases replaced with its predecessor.
The SO3C was designed in response to a 1937 request from the US Navy for a high speed scouting monoplane. This appears to have been a later specification than the one that produced the Vought OS2U Kingfisher, which was also issued in 1937, producing responses from Vought, the Naval Aircraft Factory and Stearman. A prototype of the Vought design was ordered on 6 May 1937, and made its maiden flight in September 1938, putting its development almost exactly a year ahead of the Curtiss aircraft.
Curtis submitted a design for a mid-wing monoplane, with two separate fully enclosed cockpits. It could use floats or wheels, and was powered by the inverted air-cooled Ranger V-770 V-12 engine. This was a lightweight engine, but proved to be some unreliable, with a tendency to overheat at low speeds. As a floatplane it had a large central float, with strut-mounted wing-tip stablizers. As a land plane it had wheels with large streamlined fairings. It was of all-metal construction, apart from the fabric covered control surfaces. It had thick wings, with a tapered trailing edge and straight leading edge, and slight dihedral.
A single prototype was ordered on 9 May 1938, and made its maiden flight on 6 October 1939. The prototype was found to suffer from stability and control problems. In an attempt to solve this an enlarged tail was produced, which slightly overlapped the rear cockpit (part of the fin actually slid forward with the cockpit canopy), and upturned wing tips were added.
The American name is the cause of some confusion. Curtiss originally called it the Seagull, but the British called it the Seamew. Some entries in the US Navy’s own Dictionary of American Naval Fighting Ships call it the Seagull, others the Seamew. Some state that the US Navy originally used the British name, then changed to Seagull, while others say that the US Navy started with the Seagull then swapped to Seamew!
Deliveries of the SO3C-1 began in July 1942, and it was first used on the new cruiser USS Cleveland (CL-55). The SO3C quickly proved to be unsuitable for service use, and was withdraw from service by 1944. The -1 was the first to go, with some going to the Coast Guard and some to Britain as the radio controlled Queen Seamew. Production ended in January 1944 and within a few months the type had been withdrawn from front line service. In some cases it was replaced by the older Curtiss SOC Seagull.
The SO3C was used as the initial equipment of a number of warships.
The cruiser Cleveland (CL-55) carried a detachment of SO3Cs from Cruiser Scouting Squadron 12 (VCS 12) when she entered service in the autumn of 1942, and used then during Operation Torch.
The cruiser Columbia (CL-56) carried two SO3Cs as her initial complement of aircraft. One of them was lost when it fell off the catapult on 3 January 1943 and was later replaced with a SOC-1 Seagull. On 12 January the two aircraft took off for a practise flight, and the second SO3C was also lost (the pilot was rescued). Once again the missing SO3C was replaced by a SOC-1.
The cruiser Montpelier (CL-57) was equipped with the SO3C when she entered service late in 1942. One of the aircraft stalled after being catapulted on 1 January 1943, and its two depth charges detonated, killing the pilot, Ens William T. Thompson. By 1944 she was recorded as carrying the SOC.
The cruiser Denver was equipped with two SO3Cs when she entered service late in 1942. This soon expanded to four, but several of the aircraft were lost in accidents, and by the mid-summer of 1943 she was recorded as using the SOC-3.
The cruiser Biloxi (CL-80) carried it during her shakedown cruiser in October 1943, although one of her SO3Cs crashed during a landing attempt while on the way to Trinidad. By the time she departed for the war zone early in 1944 her four SO3Cs had been replaced by two Vought OS2U-3 Kingfishers.
The SO3C was also recorded on the Boston (CA-69), as the embarked aviation unit on the the training ship USS Absecon (AVP-23) at the start of 1943 (one SO3C and two Vought OS2U-3 Kingfishers)
SO3C-1 Seagull/ Seamew
The initial production version was powered by a 450hp Ranger V-770-5 engine. It was armed with one flexibly mounted .30in machine gun in the rear cockpit and one fixed forward firing .30in machine gun. It could carry two 100lb bombs or two 325lb depth charges on bomb racks under the wings.
Orders were placed for 300 -1s, but only 141 of these were built, with the serial numbers 4730-4783 and 4793-4879.
The SO3C-1 soon proved to be a failure in its original role. Deliveries began in July 1942, and it was used to equip a number of new cruisers in the second half of 1942, but early in 1943 quite a few were withdrawn and given to the US Coast Guard. Most of these came back to the US Navy early in 1944, although they don’t appear to have entered service. Some of the -1s went to Britain where they were used as Queen Seamew radio-controlled target aircraft.
SO3C-1B (Model 82C)
This designation was given to 250 SO3C-1s that were ordered for the Royal Navy. They were all completed as the SO3C-2C.
Perhaps because it was an unsuccessful design, the sources rather disagree on the exact details of the variants of the SO3C. All agree that the -2 had a 24 volt electrical system and that 200 were built for the US Navy. The first 150 (serials 4880-5029) replaced the last 150 -1s on the production line. The remaining 50 were ordered on a new contract (serials 04149-04198). It was probably powered by the 520hp V-770-6 engine. Some sources also give it the changes that were definitely introduced on the British -2C – arrestor hook, carrier equipment and a 500lb bomb rack under the fuselage.
The -2C was the eventual designation for the 250 aircraft ordered for the British. This version had the arrestor gear to allow it to operate from aircraft carriers, and the central float could be replaced by a bomb rack capable of carrying a 500lb bomb on the wheeled version. Despite the probable increase in engine power, the -2C was slower, with a worse rate of climb and a lower ceiling that the prototype, mainly because it was also significantly heavier.
It isn’t clear how many of these aircraft actually reached British hands, with some sources say 100 were received and others listing only sixteen as being delivered. Seventy went to Canada. It was used by Nos.744 and 745 Training Squadrons, at Yarmouth, Canada and Worthy Down, Hampshire. It was used to train air gunners and wireless operators.
The SO3C-3 was slightly lighter and used the more powerful SGV-770-8 engine (probably 600hp). It isn’t clear how many of the first batch of 150 aircraft were completed (04199-04348), with figures ranging from only 39 up to all 150. Known serial numbers go all the way to 04348, which served briefly with the US Coast Guard, suggesting the 150 figure is most likely.
Another batch of 600 –3s was ordered, and were allocated the serial numbers 22257-22856, but contract was soon cancelled and the numbers reused for the Martin AM-1 Mauler.
The SO3C-4 would have been similar to the -3, but with arrester gear. The type was cancelled before any had been produced.
The SOR-1 would have been a Ryan produced version of the SO3C-1, but it was cancelled before any were produced.
The Queen Seamew was a radio-controlled target aircraft. 30 are said to have gone to the UK, where they were given serial numbers KE286-KE304 (19 aircraft) JX663-JX669 (7 aircraft) and JZ771-JZ774 (4 aircraft). Some were produced from the -1, but a sizable batch also came from the -3 production. They were transferred to the Royal Navy in the spring of 1945, so would have seen most service post-war.
Engine: Ranger V-770-6
Span: 38ft 0in
Length: 35ft 11 7/8in
Height: 15ft 3in
Empty weight: 4,800lbb
Maximum take-off weight: 7,200lb
Max speed: 172mph at 8,100ft
Cruising speed: 125mph
Climb Rate: 720ft/ min
Service ceiling: 15,800ft
Range: 1,150 miles
Armament: One fixed forward firing .3in machine gun, one flexibly mounted 0.5in machine gun
Bomb load: Two 100lb bombs or two 325lb depth charges carried below wings or one 500lb bomb below fuselage