A buoyancy control system for controlling the buoyancy of a tube may includes generally tubular length of buoyancy control material having a selected buoyancy characteristic. The length of buoyancy control material may be attached to a section of the length of the tube to adjust the buoyancy of the section of the tube. The length of buoyancy control material may be an integral, coaxial layer of the tube or, alternatively, the length of buoyancy control material may be externally attached to tube. In embodiments in which the length of the buoyancy control material is externally attached, the buoyancy control material may have a longitudinal axis that is spaced-apart from a longitudinal axis of the tube.