City of Cardiff was originally meant to be a Sunderland III, but.....:
In 30 August 1944, the prototype (MZ269) first flew from the
River Medway at Rochester. The increased engine power caused aerodynamic stability problems, and a new fin was designed with greater height with forward dorsal extension, plus a new tailplane with increased span and area.
[3] Changes were so extensive, that the new aircraft was given the name
Seaford.
[4] Thirty production aircraft were ordered, but the first of these flew in April 1945, well after the introduction of the Sunderland Mark V, and too late to see combat in Europe. The prototypes were powered by Hercules XVII engines of 1,680 hp (1,253 kW), but production aircraft used 1,720 hp (1,283 kW) Hercules XIX engines. The planned Glenn Martin tail turrets were never installed. Eight production Seafords were completed; the first (NJ200) was used for trials at
MAEE Felixstowe. The second production Seaford (NJ201) was evaluated by RAF Transport Command, then in December 1945 it was loaned without armament to
BOAC as G-AGWU, then returned to MAEE as NJ201 in February 1946. In April 1946, the other six production Seafords were delivered to No. 201 Squadron RAF for brief operational trials. In 1948, those six aircraft were modified as civilian airliners at Belfast, then leased to BOAC with the designation
Solent 3.
[5]
It is NJ203 at the Oakland Museum.
So, it was a Sunderland 3, then a Seaford, and finally a Solent 3!