No. 13008. Supermarine 340 Seafire Mk.IB (BL676) Royal Navy
Photographed aboard the HMS Victorious, May 5, 1942
Aeroplane Photo Supply (APS) Photo No. 843

Supermarine 340 Seafire Mk.IB

09/30/2016. Remarks by Johan Visschedijk: "One aspect of naval aviation that had received too little attention before WW II was the procurement of British shipborne single-seat fighters. The resurrection of German naval power posed a threat to the aircraft carriers in particular, and the subsequent acquisition of bases on the Atlantic seaboard from which air attacks against Allied shipping could be launched demanded full establishment of an up-to-date seaborne fighter force. There was neither time nor facility to design and develop a specialized type and such was the performance of the Spitfire and the Hurricane that the Admiralty requested some late in 1939.

In January 1940 Supermarine produced a design called the Sea Spitfire, fitted with an arrester hook. In addition, one was designed with folding wings, and offered for delivery in October 1940, but the First Lord of the Admiralty, then Winston Churchill, decided against it so the folding-wing Seafire did not materialize for another two years partly because of this decision but more because of the emphasis on the build-up of home fighter defense.

In the autumn of 1941 the Admiralty finally obtained permission to acquire Sea Spitfires and the Air Ministry received a request for the conversion of 400 Spitfire Mk,VCs, but only 48 Mk.VBs and 202 Mk.VCs were offered. The first aircraft to be fitted by Supermarine with an arrester hook was a Spitfire Mk.VB (serial AB205), which first flew on January 7, 1942, as a Hooked Spitfire. It was weighed at Worthy Down in January 1942 under Supermarine Type 340 and later called the Seafire Mk.I, the tare weight being 5,013 lb (2,274 kg), and all-up weight 6,591 lb (2,990 kg).

The next Spitfire Mk.VB airframe to be converted was AD371, again by Supermarine, being weighed at Worthy Down on February 15, 1942, under Type 357 and called Seafire Mk.II. This aircraft was fitted with a deck arrester hook and catapult spools, the weights increasing to 5,064 lb (2,297 kg) and 6,642 lb (3,013 kg) respectively.

Urgency was now put on Seafire production and orders were placed with Air Service Training (AST) of Hamble for 48 (serials MB328 to MB375) and with Cunliffe-Owen Aircraft at Eastleigh for 118 (NX879 to NX928, NX940 to NX967, NX980 to NX989, PA100 to PA129), all conversions of Spitfire Mk.VBs. Supplementary contracts involved the production of arrester hooks which were fitted to Spitfires by RAF Maintenance Units. Known as Hooked Spitfires they were used by the Royal Navy for shore-based training, though some were actually operated from carriers later.

The first Seafire conversion was a Spitfire Mk.VB, BL676, during January-February 1942 by AST, being fitted with an arrester hook, slinging points, and ballasted weights in the nose to correct the centre of gravity. It was tested at Worthy Down during March, and was flown by Lt.Cmdr. H.P. Bramwell to Arbroath on March 8 for initial deck-landing trials aboard HMS Illustrious.

These trials were successful and two variants were scheduled for production, the Seafire Mk.IB with Spitfire Mk.VB mainplanes and the Seafire Mk.IIC with Spitfire Mk.VC mainplanes, the suffixes being added from the original Spitfire versions. The design man hours for the Seafire Mk.I were 10,130 and for the Seafire Mk.II only 3,685 compared to the 339,400 for the Spitfire Mk.I, 90,000 approximately for the Spitfire Mk.V and 43,830 for the Spitfire Mk.IX. BL676 flew on sea trials during March and April 1942 from HMS Victorious (shown above) off the Orkneys and again everything went satisfactorily, the only adverse comment being in relation to the view forward and downward. It was re-numbered MB328 as the first of the batch MB328 to MB375.

Following the first trials of AB205 showing that a Spitfire could be successfully flown off a carrier, fifteen normal Spitfires were flown off HMS Eagle on March 7, 1942, for Malta under Operation Spotter, and all reached the beleaguered island safely. These were followed on April 20 by the takeoff of 47 Spitfire Mk.VBs of 601 and 603 Squadrons from the carrier USS Wasp under Operation Calendar of which it is reported 46 arrived. On May 9 further reinforcements were sent by the takeoff of 47 more from the Wasp and 17 from the Eagle, of which 59 safely arrived at Malta at a most critical period in the history of the island.

One Spitfire returned to the Wasp and subsequently landed safely without an arrester hook, much to the surprise of all concerned because of the then high approach speed of 85 mph (137 kmh). This really proved the potential of the Spitfire, and its success over Malta was another pointer for its use from aircraft carriers. The Admiralty's operational philosophy had been changed from the use of the long-range Grumman Martlet fighter, with which the Fleet Air Arm was equipped, to the short-range interceptor Seafire, whose range indeed was its limitation but showed 50 mph (80 kmh) speed advantage over the Martlet.

The conversions of the Spitfires to Seafires were required as soon as possible and so the modifications were as few and as simple as possible. The A-frame arrester hook was hinged to the bottom longerons of fuselage frame 15, with legs 6 ft (1.83 m) long. I was operated by a scissors-type snap gear holding the bill of the hook and released by the pilot via a Bowden cable and a lever in the cockpit; however. the hook could be lifted only by ground staff. Because of the extra stress imposed on the aft airframe, local strengthening was incorporated on the bottom longerons at the hook and also to the damping jack hinge-points. To reduce drag the A-frame was faired to the lower fuselage so only the hook's bill was left in the airflow. Slinging points with local strengthening were provided for use by the Royal Navy.

With these modifications, speed was reduced by 5 mph (8 kmh) and empty weight increased by five per cent and so compared fairly favorably with its land counterpart, the Spitfire Mk.VB. Only MB328 to 375 were fitted with tropical radiators and oil coolers and supplied complete with both temperate and tropical air intakes. The first Seafire Mk.IB is recorded as being taken on charge on June 15, 1942, though most of them were routed from AST to Eastleigh for 38 MU and 76 MU and to Glasgow Docks, MB329 reaching the docks with MB330 on July 7 for shipment to HM ships.

The only squadron to be completely equipped with the Seafire Mk.IB was 801 which was embarked in HMS Furious from October 1942 until September 1944. As Furious had T-shaped lifts, the aircraft could be struck below and with no catapult the lack of spools on the Seafires did not matter. The second squadron to receive them was 842 but not until the summer of 1943 when they were embarked on the escort carrier Fencer. Other units to have them on strength were 1 and 2 Naval Fighter Schools at Yeovilton and Henstridge respectively, the School of Naval Air Warfare at St Merryn, RNAS stations at Lee-on-Solent and Stretton and 760 (R) Sqn. at Yeovilton."

Created September 30, 2016