The Wormhole wrote:
They are supposed to be seperate classes, the primary difference being the K't'inga has an aft torpedo launcher and the D-7 does not. There's also differences in size and surface details. Presumably the D-7 is an older ship to account for why there's none of them in the 24th century but still plenty of K't'ingas, even during the Dominion War.
Alternatively, in the real life militaries of the world, there have been cases where older ships/planes continued in service even after newer ones had been retired.
So, the D7 could have been a 23rd century version of the 22nd century K'Tinga, that was phased out in favour of the baseline model.
Convoluted really - but it is possible.
I wish they had just used the D4 model in ENT 'Unexpected' - it took tons of labour to create - the design was good looking - it was done for free in overtime - and the producers just told them "it has too few windows" and put the K'Tinga in (wtf?)