The Ber'taa-class was a Klingon starship class that was fielded in the 23rd century. It was quickly put out of service (as the K'vort Cha-class about a hundred years later) just as it was put in service because of several design flaws. They were replaced by the PumwI'-class and the QeylIS BetleH-class. (TOS video game: Klingon Academy) One of the memorials above Hydrax was a wrecked ship of this class. (RIS Bouteina: "Limit at Minus Infinity")