Alan Erskine wrote:

Oops. ;-) I meant, why wasn't there an S-1? Was it due to the 1960's
nomenclature change?


The first purpose-built ASW aircraft was the Grumman AF Guardian, it
preceded the S designation for such aircraft. The second purpose-built ASW
aircraft was the Grumman S2F Tracker. It was designated S2F because it was
the second ASW aircraft built for the Navy by Grumman. With the Tri-Service
designation system the S2F became the S-2. Why not S-1? Probably just to
keep things as simple as possible.