PP Rope 3 or 4 Strands Marine Fishing Rope Nylon ThreadTwisted Polypropylene PP Rope

1. General Description

QINGDAO JINCHENG MARITIME has serial products including varieties of nylon, polypropylene filament, polypropylene, polypropylene /polyester mixed, polyester. It started a new epoch of rope and cable industry in the country and its products have advantages of reasonable braided structure, scientific technology, high strength, low elongation,wearing resistance, anti-corrosion and simple operation, it is particularly suitable to make large scale ropes and cables as well as anti -static ropes therefore they are well received by broad customers, The products are mainly used in fields of shipbuilding, ocean transportation, national defense and military industry, sea petroleum and harbor operation etc.

2. Main performance

3.Technology Comparison

Coil length: 220m

Spliced strength:± 10% lower

Weight and length tolerance:±5%

MBL=Minimum Breaking Load conform ISO 2307

Other sizes available upon request

4.Parameter Table

Production Process

Step 1: Raw Material Preparation & Fiber Extrusion

• Polypropylene (PP) Pellet Processing: Start with high-quality polypropylene pellets (selected for marine resistance, UV stability, and tensile strength). The pellets are fed into an extruder, where they are heated to a molten state (around 180–220°C) and pushed through spinnerets to form continuous PP filaments. These filaments are cooled rapidly with air or water to solidify, then stretched to align the polymer molecules—enhancing the fiber’s strength and reducing elongation.
• Nylon Thread Integration: Parallelly, pre-drawn nylon threads (chosen for added toughness and shock absorption) are prepared. Depending on design requirements, nylon threads are either blended with PP filaments during extrusion or kept as separate strands for later integration, ensuring compatibility with marine and fishing environments.

Step 2: Strand Formation (Yarn Spinning & Twisting)

• Yarn Spinning: The solidified PP filaments (and nylon threads, if blended) are gathered into yarns of specified thickness. Multiple filaments are twisted together to form primary yarns, which are then wound onto bobbins. For 3-strand or 4-strand ropes, the number of primary yarns per strand is calibrated to achieve the target diameter and load-bearing capacity.
• Pre-Twisting of Strands: Each set of primary yarns (now designated as “strands”) undergoes pre-twisting. This step adds initial stability to the strands, preventing fraying and ensuring uniform tension during the final twisting process. Nylon threads may be incorporated as a core or outer layer within each PP strand to boost durability.

Step 3: Final Twisting (Rope Forming)

• Strand Assembly: Three or four pre-twisted PP strands (with integrated nylon threads) are mounted on a twisting machine. The machine rotates the strands in a controlled direction (either right-hand or left-hand twist) to braid them into a single, cohesive rope. The twist density is adjusted—tighter twists enhance abrasion resistance, while moderate twists balance flexibility and strength, critical for marine fishing use.
• Tension Control: Throughout twisting, constant tension is maintained across all strands to ensure even distribution of fibers. This prevents uneven wear or weak points, ensuring the rope meets marine-grade standards for load-bearing and durability.

Step 4: Post-Processing & Quality Inspection

• Heat Setting & Stabilization: The newly formed twisted rope is passed through a heat-setting chamber to lock in the twist structure. This step reduces “spring back” (unraveling) and improves dimensional stability, especially when the rope is exposed to water or temperature changes in marine environments.
• Surface Treatment (Optional): For enhanced performance, the rope may undergo a surface coating (e.g., UV inhibitors or anti-fouling agents) to resist sun damage and minimize marine organism attachment. It is then cooled and wound onto large spools or cut into custom lengths.
• Quality Testing: Samples from each batch are tested for tensile strength, abrasion resistance, water absorption, and UV stability. Only ropes meeting marine and fishing industry standards (e.g., resistance to saltwater corrosion, minimal stretch under load) proceed to packaging.

Step 5: Packaging

• The finished 3/4-strand PP ropes are packaged in moisture-proof materials (e.g., woven plastic bags or cardboard tubes) to protect them from dust, moisture, and damage during storage and transportation, ensuring they reach end-users in optimal condition.

2. Application Scope

Marine Vessel Operations

• Mooring & Docking Lines for Small Vessels: Ideal for mooring small fishing boats, dinghies, or recreational craft to docks, piers, or buoys. Its PP core resists saltwater corrosion, while nylon threads add shock absorption to handle wave-induced tension, preventing damage to the vessel’s cleats or hull.
• Towing Lines for Fishing Gear: Used to tow lightweight fishing equipment (e.g., small nets, bait containers, or auxiliary floats) behind fishing boats. The rope’s moderate flexibility allows easy handling, and its resistance to water absorption ensures it remains lightweight during long towing sessions.

Commercial & Recreational Fishing

• Fishing Net Support & Securement: Serves as a support rope for hanging fishing nets (e.g., gill nets, cast nets) on boats or along shorelines. The twisted structure provides stable tension to keep nets taut, while nylon threads enhance durability against friction from netting materials and marine debris.
• Landing Ropes for Catches: Used to haul small to medium-sized fish catches from the water to the boat. Its tensile strength handles the weight of catches, and its non-slip surface (from twisted PP) ensures a secure grip, even when wet. It is also resistant to fish scales and slime, making cleanup easy.
• Buoy & Marker Lines: Deployed as lines for securing fishing buoys (e.g., depth markers, trap markers) in coastal or offshore waters. The rope’s UV stability prevents degradation from prolonged sun exposure, and its low water absorption keeps buoys properly positioned without excess weight dragging them down.

Aquaculture (Fish Farming)

• Pen & Cage Securement: Used to secure small aquaculture pens (for raising fish or shellfish) to the seabed or floating structures. Its resistance to saltwater and marine organisms (e.g., algae, barnacles) ensures long-term use, while nylon threads add flexibility to adjust pen positions with changing tides.
• Feeder Line for Aquaculture: Functions as a line for hanging or guiding automatic fish feeders in aquaculture systems. The rope’s durability withstands constant contact with water and feed residues, and its twisted design prevents tangling with feeder components.

Lightweight Marine Maintenance & Emergency Use

• Temporary Repairs on Boats: Used for temporary fixes on fishing boats, such as securing loose equipment (e.g., covers, tools) or patching small gaps in canvas awnings. Its easy-to-tie nature and moderate strength make it a practical emergency tool.
• Safety Lines for Small Craft: Serves as a lightweight safety line for crew members on small fishing boats (e.g., when moving across the deck). While not intended for heavy-duty fall protection, it provides a secure handhold, and its bright color (common in PP ropes) enhances visibility in low-light conditions.