Abstract: A negatively buoyant tether cable management apparatus for use with a remotely-operated underwater vehicle is disclosed. The apparatus includes a cable climbing assembly, a depth sensor and a controller coupled to the climbing assembly and formed to actuate the climbing assembly to climb the tether cable when the cable management apparatus has been lowered to a predetermined depth. The climbing assembly includes a pair of powered, ribbed belts which are wrapped at least partially around the periphery of the tether cable at an acute angle to the cable. As the tether cable is lowered further, the climbing assembly climbs to maintain the depth and passes the tether cable out below or beyond the climbing assembly to enable maneuvering of the remotely-operated underwater vehicle with respect to the negatively buoyant cable management apparatus.