The Streamlass was a single-sailed raft that was the home of the Witherspyk Performing Players. It was commandeered and steered by the group's leader, Oakheart Witherspyk. A large blockhouse constructed out of logs was located in the center of the raft.
Oakheart fell asleep at the tiller and subsequently ran the Streamlass aground one day, but it was freed from the rocks where it was trapped by Jango Bigboat and his Guosim. The Witherspyks then sailed with the Guosim to a watermeadow, and journeyed from there to Redwall Abbey on foot. As Abbess Marjoram mentions later that the Witherspyk players decided to stay at Redwall as permanent residents, it is unknown what became of the raft.