According to Jeff Wright, a technical adviser for the Michigan-based company, carbon tape is ideal for adding stiffness to parts of a boat that may have been underbuilt, such as hatch covers or longitudinal stringers. Like fiberglass tape, carbon tape is applied using epoxy; unlike fiberglass tape, which is generally woven in two directions, West System's carbon tape is unidirectional. All the fibers point the same way, so the tape only adds strength in that direction. Like the wood grains in a 2x4, the carbon fibers in the tape are strongest when they run parallel to the force being applied. "Carbon tape is great for adding tensile strenth and tensile modulus (stiffness)," says Wright. "Think of it this way: If you were to take a single carbon fiber and pull on it, it would be plenty strong. But if you were to push on it from the side, it's going to bend."