From PathfinderWiki
Class Cog
Keel 65 ft.
Beam 20 ft.
Propulsion Three sails
Fate Presumably adrift or wrecked somewhere on the Sellen River
Crew 6-12

Source: Perils of the Pirate Pact, pg(s). 5-7

The river pirate vessel Waverender was last seen crew-less and in an advanced state of disrepair on the Sellen River in 4709 AR.[1]