75–350 mm Marine Three-Roller Chock | CB/T 38-1999 Type C with Cast Steel

Product Specification

75–350 mm Marine Three-Roller Chock | CB/T 38-1999 Type C with Cast Steel Rollers

Product Overview
Marine three roller chock is designed to guide mooring ropes through a fixed opening while reducing friction and controlling rope direction.
Compared with conventional chock, the integrated three-roller structure allows multi-direction rope lead and significantly reduces local stress and rope wear.
This product follows CB/T 38-1999 Type C standard, replacing CB39-66 Type C.
CB/T 38-1999 adopts a welded base structure, providing improved load transfer and higher structural integrity compared to bolt-on CB39-66 design.
Each model corresponds to a specific rope breaking load (MBL), enabling accurate load-based selection.
 
Quick Specifications

• Structure: Three rollers → Multi-direction rope guidance
• Applicable Rope Diameter: 7–37 mm → Standard selection range
• Applicable Rope MBL: 23–583 kN → Key selection parameter
• Mounting: Welded base (CB/T 38-1999) / Bolt-on (CB39-66 replacement)
• Material: Casting steel → High strength and durability
• Surface: Smooth machined → Protect rope
• Certification: CCS, NK, BV, ABS, DNV, LR, KR, IRS, RS, RINA, CRS, Makers Test Certificate

Main Technical Parameters (CB/T 38-1999 Type C)

 
Load & Selection Basis
The 'Rope Max Break (kN)' refers to the maximum breaking load (MBL) of the applicable rope.
Each chock size is matched to a corresponding rope strength level.
Reference SWL ≈ Rope MBL ÷ Safety Factor (typically 1.5–2.0).
The chock is designed to withstand loads equal to or exceeding rope breaking strength, ensuring structural safety under extreme conditions.
 
Selection Guide
Step 1 – Select rope diameter → Based on mooring line size
Step 2 – Confirm rope breaking load (MBL) → Primary selection parameter
Step 3 – Select chock size → Match both rope diameter and MBL
Step 4 – Confirm installation type → Welded (newbuild) / Bolt-on (replacement)
Step 5 – Confirm certification requirement
 
Engineering Note
CB/T 38-1999 introduces load-based matching, where each model corresponds to a specific rope breaking strength.
This ensures better alignment between mooring system design and actual operational loads.
 
Structure
Three rollers | Casting body | Welded base | Reinforced structure
 
Custom Attributes
Three-roller design → Load distribution and reduced rope wear
Free rotating rollers → Minimize friction
Casting steel body → High strength
Smooth contact surface → Protect rope
 
Inquiry Guide
Provide rope diameter, rope MBL, installation type, vessel type and certification requirements.
How It Works
Rope passes through chock → rollers rotate → friction reduced → rope guided smoothly → wear minimized.
 
Applications
Ship bow | Ship stern | Bulwark | Deck edge mooring
 
Certifications & Advantages
Certification: CCS, NK, BV, ABS, DNV, LR, KR, IRS, RS, RINA, CRS, Makers Test Certificate
 
Drawing & Photos
General arrangement drawing and product photos


 
Ordering
Specify: size, material, coating, certification
 
FAQ
Q1: Why use three roller chock?
A: To reduce friction, distribute load and protect mooring rope.
Q2: Do rollers rotate?
A: Yes, all rollers rotate freely to minimize wear.
Q3: How to select size?
A: Based on rope diameter and breaking load from the table.
Q4: Which standard should I choose for my project?
A: For newbuild projects, updated standards such as CB/T 38-1999 or classification society requirements are recommended.
For existing vessels, CB 39-66 dimensions are typically used for direct replacement.