The Stopdog was a double-sailed ketch. It originally belonged to three Ratguard searats, but was stolen by Kroova Wavedog. They called out "Stop, dog!" as he made off with it, hence the name. Kroova used the ketch to transport Sagaxus and Bescarum from the mountain of Salamandastron in search of adventure.
The ship was accidentally burned when its passengers were captured by Plugg Firetail's Freebooters. Slitfang mentioned that the ketch previously belonged to Sarengo in the past.