As many as 40 torpedoes were found in some bends of the river. Union troops intending to operate with the gunboats weer delayed.
By the time they were ready to advance on Rainbow Bluff, the Confederate garrison there had been strongly reinforced.
Torpedoes in the river, batteries along the banks below that point, and the difficulty of navigating the river forced the abandonment of the operation. The wrecks of the Ostego and Bazely were destroyed to prevent their falling into Confederate hands on December 25th. The expedition got back to Plymouth three days later.