Abstract: A portable reel apparatus for use with towed sonar towfish and similar apparatus. The reel apparatus of the invention can be used on small watercraft without requiring mounting to the deck, and can be quickly and easily moved and stored on-board or removed from the watercraft. The portable reel assembly comprises a frame assembly, a spool rotatably mounted within the frame assembly, an extensible boom, and an electronic interfacing assembly for maintaining communication between a sonar cable through the spool to a computer. The apparatus can be moved or repositioned between a first, deploying position and a second, storage position. The frame assembly is preferably wheeled for transporting the apparatus, and a motor for driving the spool is preferably included within the frame assembly.