In this task, you are given a sentence or phrase in Xhosa. You must translate it to English in a way that is equivalent in terms of meaning and grammatically correct.

Iiklasi zokuqala zamaphenyane emipu zayilwa okokuba zingathathi indawo yezikhephe ezineemasti ezimbini kodwa zenze imisebenzi eyodwa kwiBhalthikhi nakwiBlack Sea.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
As a result, the first classes of gunboats were designed not to replace the brigs but for specialised duties in the Baltic and Black Sea.