towline

A towline is a rope, line, or cable used to tow another vessel, vehicle, or object. In maritime operations a towline connects a tug, barge, or salvage craft to the towed unit, transmitting pulling force and enabling controlled movement during berthing, docking, rescue, or salvage work. Towlines are attached to designated tow points and are retrieved by winches or bollards as required.

Materials and construction. Historically made from hemp or Manila, towlines today are largely synthetic or steel. Common marine towlines use nylon, polyester, polypropylene, or HMPE fibers (such as Dyneema), chosen for strength, stretch, abrasion resistance, and buoyancy. Nylon provides elasticity to absorb shocks; polyester offers low stretch and good UV resistance; HMPE delivers high strength with relatively low weight. Heavy towing may employ steel wires or wire ropes with protective jackets. Some lines are buoyant to aid handling afloat.

Operations and safety. Towlines are specified by breaking strength and working load limits and are selected for expected loads, length, and conditions. Safe use requires proper attachment to tow fittings, protective sleeves or chafing gear, regular inspection for wear, and careful handling to prevent line fraying or whiplash if the line parts. In aviation or land-based towing, towlines may be used with tow tractors or aircraft nose gear, following standardized procedures to ensure control and safety.