AH features what must be the worst Seafire marque ever made.
The first 163 Seafire Ib were converted from existing Spitfire Va and Vb, and a few IIb airframes. Simply put, they were Spitfires with a hook and catapult gear. Delivery began in June 1942.
Also delivered in June 1942 was the Seafire II - which were made from scratch as naval fighters, based on the Spitfire Vc airframe. The model featured in AH, the Seafire IIC with the Merlin 45 was the dog of the line. It was some 15mph slower than the Seafire Ib(Spitfire Vb).
372 Seafire Mk II were produced in total - but only the first batch had the Merlin 45 - after Operation Torch the low-altitude Merlin 32 engine(~1600HP) was fitted, driving a 4-blade propellor. These planes(delivered in November 1942) were called the Seafire L.IIC. The existing Seafire IIC's were retrofitted with the Merlin 32 until eventually all were converted to the L.IIC standard.
The more powerful engine improved top speed to 316mph at s/l, and 335mph at 6,000ft. Initial climbrate was over 4,500fpm.
The Seafire L.IIC was in service until late 1944.
Then came the Seafire III. It had folding wings, a Merlin 55 engine(similar to M45) of 1470HP, and other various small improvements. The first deliveries were in November 1943.
After the first 103 Seafire III, the engine was replaced with the Merlin 55M which had cropped supercharger impellors to improve low altitude power(~1,600hp). It was redesignated the Seafire L.III. The Seafire L.III was the most produced Seafire - over 1,100 were made.
Top speed of the Seafire L.III was 331mph at s/l, 348mph at 6,000ft, and initial climbrate was 4,160fpm. The Seafire L.III was in service right up to the end of WW2.
The Seafire XV was next, with a Griffon engine, but it was too late to see action in WW2.