ISO 13729 Closed Mooring Chock
A closed mooring chock is a critical mooring and towing device installed on the side of the hull or the edge of the deck, designed to safely guide ropes from inside the vessel to the outside. Engineered for high-intensity maritime operations, these chocks are commonly used on vessels that employ steel wire ropes or synthetic towlines.
Through precision casting and strict dimensional control, OLIPORTS ensures that the contact surface radius of every closed mooring chock meets industry standards—no less than 12 times the diameter of the wire rope—thereby minimizing rope fatigue and extending service life.
Whether used for standard container vessel mooring or specialized merchant ships, every Closed chock OLIPORTS manufacture features an optimized inner surface curvature. This advanced design minimizes rope friction, thereby significantly extending the service life of heavy-duty steel wire ropes and modern synthetic ropes.
Universal Standards Covered by OLIPORTS
OLIPORTS not only offer standard closed mooring chocks for sale, but also ensure precise engineering compliance. Below is an overview of the major international design standards for cast steel mooring fittings manufactured at our foundry:
| Design Standard | Main Models | Target Market / Application | Key Advantage |
|---|---|---|---|
| JIS Standard | IS F2017 Type AC & BC | East Asian shipyards (China, Japan, South Korea) | Traditional durability and excellent value for money for steel wire ropes. |
| ISO Standard | ISO 13729 Type A (Bulwark) & Type B (Deck) | Modern VLCCs (Very Large Crude Carriers) and ultra-large container ships), and offshore platforms | Inner arc radius ≥12× rope diameter (D/d ratio), ideal for high-end synthetic ropes and heavy-duty wire ropes |
| DIN Standard | DIN 81915 Type A, B, C, D | European shipowners, specialized dredgers | The dimensions are extremely precise, ensuring a very high safety margin even in rough sea conditions. |
Choose Your Mounting Configuration
To simplify your purchasing process, we have categorized our products by installation method. Click the links below to explore the detailed technical subpages:
Type A – Bulwark Mounted Closed Chock
Designed specifically for direct embedding and welding to the ship’s side plates. The OLIPORTS Type A closed mooring chock features a space-saving design that provides unobstructed guidance for mooring lines while maintaining the structural integrity of the hull.
Complies with standards: ISO 13729, JIS F2017 Type A/ACX, DIN 81915 Type A.
Type B – Deck Mounted Closed Chock
Equipped with a heavy-duty cast steel base, it can be welded directly to the main deck. The OLIPORTS Type B closed mooring chock is ideal for deck areas without bulwarks, or where mooring lines need to be raised above deck level to provide additional headroom.
Complies with standards: ISO 13729, JIS F2017 Type B/BCX, DIN 81915 Type B/C.
Selection Guide
Confirm rope parameters: Provide the wire rope diameter (d) and maximum working load (SWL), and OLIPORTS engineers will automatically match closed chock specifications where D/d ≥ 12.
Select installation type: Choose the Deck Mounted Closed Chock (Type A) if deck space is sufficient; select the Bulwark Mounted Closed Chock (Type B) if the cable needs to pass through the bulwark.
Submit technical drawings: OLIPORTS supports customization of non-standard dimensions, reinforced bases, or special surface treatments (such as epoxy coating/hot-dip galvanizing) based on shipyard drawings, and provides welding procedure qualification support.
Quotation and Delivery Timeline: Standard specifications ship within 5–7 business days; packaging includes classification society certificates (waterproof wooden crates + rust-proof film), and OLIPORTS provides full logistics tracking.
Why Choose OLIPORTS?
OLIPORTS supports production strictly in accordance with customer technical requirements: material grades, machining tolerances, bearing types, hardness (HRC), and special surface treatments can all be customized.
Full Traceability of Quality: Every closed mooring chock comes with a material certificate, chemical composition analysis report, and dimensional inspection record, ensuring full traceability from raw materials to finished products.
Global Project Experience: OLIPORTS have consistently supplied bulwark-mounted closed chocks and deck-mounted closed chocks to shipyards and EPC contractors in Singapore, Rotterdam, Dubai, Houston, and other locations. These products are widely used in bulk carriers, oil tankers, and offshore platform projects.
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