Open Chock for Sale

Welcome to OLIPORTS, a top-rated open chock manufacturer/supplier China. Backed by robust production capabilities and a rigorous quality assurance system, we provide reliable solutions for marine mooring equipment to customers worldwide. Whether you need standard deck mounted open chocks or custom open chocks, OLIPORTS can meet your needs.

What is an Open Chock?

An open chock is a key marine chock installed on a ship’s bulwark or deck. Unlike a closed chock, it features an open (typically angled) design that allows mooring lines to be easily and quickly fed in from above without having to thread them through from the line end. As a fundamental component of marine mooring equipment, its core function is to guide mooring lines or wire ropes from the ship’s winch to the dock, reducing friction and preventing rope wear during mooring operations. Depending on your vessel’s specific layout, we offer deck-mounted open chocks and bulwark-mounted variants designed to withstand immense breaking loads in harsh marine environments.

All OLIPORTS’ open chocks are manufactured using a one-piece casting process, ensuring a flawless structure. As a professional supplier of marine chock types, our products ensure that ropes slide in and out smoothly even under extreme conditions.

Technical Specification of Open Chock

Open Chock

Material: Cast Iron or Cast Steel
Type: SC Type & FC Type
Nominal Size: 150mm to 400mm
Weight: 10.7KG to 98KG
Certification: ABS, DNV-GL, LR, BV, CCS
Tags: Open Chock; Deck Mounted Open Chock;
Category: Mooring Chock; Marine Mooring

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Key Features of Open Chock

Rope Guide: Its U-shaped or V-shaped opening design guides the rope from the deck to the ship’s side, preventing the rope from rubbing against the hull and becoming damaged.

Hull Protection: By securing the rope’s path, it prevents the rope from swinging violently when the vessel is rocking, thereby protecting the hull paint and deck equipment.

Ease of Operation: It features a larger opening, making it easier for crew members to thread the rope through during mooring operations and improving operational efficiency.

Open Design: Unlike the Closed Chock, it lacks a top cover, allowing the rope to be inserted directly into the channel from above.

Material: Typically made of cast steel and coated with red anti-rust paint to withstand harsh marine environments.

Production Standards: OLIPORTS strictly adheres to international standards. Our open-type cable glands fully comply with JIS F 2006 for open-type cable glands, as well as ISO 13713 standards.

Open Mooring Chock Dimensions and Drawing

SC Type Open Chock
Nominal size (mm)	Weight (kg)	Dimensions (mm)							Wire Rope Dia.
Nominal size (mm)	Weight (kg)	L	L1	L2	B	H	H1	H3	Wire 6*24	hemp	P.P
150	10.7	150	280	60	80	90	70	118	12	32	20
200	18.1	200	380	84	110	116	92	151	14	38	24
250	29.2	250	460	114	130	136	108	178	16	42	28
300	44	300	540	140	150	160	124	209	18	50	32
350	64	350	620	170	170	180	140	235	20	55	36
400	98	400	700	200	200	200	160	263	22	60	42

FC type open chock diemnsions and drawing

FC Type Open Chock
Nominal size (mm)	Weight (kg)	Dimensions (mm)							Wire Rope Dia.
Nominal size (mm)	Weight (kg)	L	L1	L2	B	H	H1	H3	Wire 6*24	hemp	P.P
150	11.5	150	400	60	80	85	75	120	12	32	20
200	19	200	500	80	110	105	96	147	14	38	24
250	31.5	250	600	110	130	125	111	174	16	42	28
300	47	300	700	140	150	145	127	203	18	50	32
350	68	350	800	165	170	160	140	225	20	55	36
390	91	390	900	190	190	175	155	245	22	60	42
420	130	420	1000	210	210	195	172	272	22	60	42

Need help selecting the right model? We can provide free drawings for your vessel right away!

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How to select open chock for your vessel?

Determine the Safe Working Load (SWL): Calculate the maximum breaking load of the mooring line. The SWL of the mooring open chock must exceed this value and include an appropriate safety factor (typically 3:1 or higher).

Select Installation Type: Based on the vessel’s freeboard and deck layout, determine whether to use a deck-mounted open chock (flush-mounted on the deck surface) or a bulwark-mounted open chock.

Select Material: For ocean-going vessels and heavy-duty applications, cast steel open chocks are strongly recommended. For smaller vessels or light-duty applications, cast iron is sufficient.

Consider Customization: If your vessel has unique structural requirements, we offer design and manufacturing services for custom open chocks to fully meet your specific specifications.

OLIPORTS Selection Support:

Our engineering team offers free technical consultations to help you select the best marine chock types for your specific application. We provide:

Assistance with SWL calculations based on vessel displacement and mooring configuration
3D modeling prior to production to verify compatibility
Material recommendations based on operating conditions (seawater corrosion resistance, low-temperature toughness, etc.)
Rapid prototyping for custom open chock designs

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FAQ

What is the difference between a cast steel open chock and a cast iron open chock? How should I choose between them?

The main differences lie in tensile strength, impact toughness, and durability. Cast steel open chocks (SC type) offer high strength and excellent impact resistance, making them the preferred choice for ocean-going vessels, heavy mooring lines, and harsh sea conditions. Cast iron (FC type) is more brittle and has a lower load-bearing capacity, making it suitable only for small inland waterway vessels or light-duty applications. At OLIPORTS, to ensure maximum safety, we strongly recommend the use of cast steel open chocks in 95% of commercial vessel projects.

What surface treatment process does your company use for its marine mooring equipment to prevent severe marine corrosion?

Corrosion resistance is critical for any marine mooring equipment. At OLIPORTS, our standard surface treatment process includes:
Sandblasting: Cleaning the surface to Sa 2.5 grade to remove all rust, scale, and contaminants.
Primer Application: Applying a high-quality marine zinc-rich epoxy primer (minimum thickness 80 μm).
Topcoat application: Application of durable asphalt paint or polyurethane topcoat (minimum thickness 120 μm) according to customer requirements.
For specific ship chock applications requiring an exceptionally long maintenance-free service life, we also offer hot-dip galvanizing services.

What is the main difference between open chocks and closed chocks?

The main difference lies in the design of the top structure and the efficiency of rope deployment. Open chocks feature an open-top design (typically with two corners), allowing crew members to feed mooring lines or synthetic ropes directly into the chock from above without having to thread the rope from the end, enabling rapid deployment during emergency mooring. In contrast, closed chocks (such as the Panama chock) feature a fully enclosed ring structure. While they offer greater safety against multidirectional loads, they require the rope to be threaded through, making mooring operations slightly more time-consuming.

What key dimensions need to be measured when replacing an old open mooring chock?

You need to measure three key dimensions: 1) the width of the chock opening (to ensure the rope can pass through smoothly); 2) the length and width of the base (to match the welding or bolt holes on the deck); 3) The height of the chock (to ensure the rope does not rub against the deck edge). As long as you provide these three dimensions, OLIPORTS engineers can quickly match you with a suitable custom open chock or standard part based on the open mooring chock dimensions and drawing.

Request a Quote or Drawing

OLIPORTS offer: Technical Datasheet PDF、Material Certificates、DWG or STEP files for design integration、On-request layout support. Our lashing experts typically reply within 24 hours. 💡 Based on your port design, berthing energy, and vessel data, we’ll provide:
⚙️ Recommended drawings & specifications
💬 A tailored quotation with best lead time
📎 Support for class approval documents

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