Airhead Bungee Dock Lines While most dock lines are made from braided static nylon rope, either three-ply or higher, in recent years, flexible bungee-style dock lines have entered the market. Bungee dock lines secure boats at the dock more easily than static ropes, with more give and flex to absorb shock. These dock lines feature an inner cord and are covered with a nylon fabric casing. The casing protects the dock line from UV damage and deterioration leading to longer service life. Airhead Bun