When that fleet was destroyed over planet Tezwa by Federation-built nadion-pulse cannons and Starfleet observed an invasion force leaving Qo'noS to conquer the planet, there was a strong possibility that an unknown number of cloaked ships would from there join the original twenty ships. In the end, over sixty ships were disabled over Tezwa, among them the lead ship IKS veScharg'a and the IKS Ya'Vang. (TNG - A Time to... novel: A Time to Kill)