Marine Anchor Chain Wheel

A marine anchor chain wheel, also known as a chain wheel or chain roller, is a critical component in a ships anchoring system. It is typically installed on a windlass or winch and used to guide, deploy, retrieve, and secure the anchor chain, ensuring the ships stability when anchored.

The marine anchor chain wheel is a rotating component on the windlass, usually a circular wheel with specially designed recesses (chain pockets or chain grooves) on its surface. These recesses precisely engage with the links of the anchor chain, driving the deployment and retrieval of the chain. It is the core component connecting the anchor chain and the windlass in the anchoring system, ensuring smooth operation of the anchor chain and withstanding the enormous tension during anchoring.

Main Functions

• Guiding the Anchor Chain: By engaging with the anchor chain links through the chain grooves, it ensures that the anchor chain does not slip or fall off during deployment and retrieval.
• Transmitting Power: The anchor chain wheel is driven by the windlasss motor or hydraulic system, moving the anchor chain up and down to achieve anchoring or heaving up the anchor.
• Bearing Loads: The anchor chain wheel must withstand the tension of the anchor chain and the dynamic loads of the ship in wind and waves.
• Preventing Chain Jumping: Designed with chain-grabbing devices (such as chain stoppers or chain hooks) or specific groove shapes to prevent the anchor chain from detaching during high-speed operation or when subjected to force.

Design and Structural Features

• Shape and Structure:
  • Anchor chain wheels are usually circular castings or forgings, connected to the windlass main shaft at the center, with 5-7 chain pockets (chain-grabbing grooves) on the surface, matching the anchor chain size.
  • The shape of the chain pockets corresponds precisely to the anchor chain links (with or without studs), ensuring tight engagement.
  • Some anchor chain wheels integrate braking devices or clutches for easy control of anchor chain movement.
• Dimensions: Designed according to the anchor chain diameter (12.5mm~120mm), common specifications correspond to ship tonnage (e.g., 5,000~100,000 DWT).
• Types:
  • Stud Link Chain Wheel: Used for stud link chains, the chain pocket design is more complex to ensure the studs are embedded.
  • Studless Chain Wheel: Used for studless chains, mostly used for small ships or temporary anchoring.
• Installation: The anchor chain wheel is fixed on the windlass main shaft, usually located at the front end of the ships deck (forecastle area), connected by bolts or keyways to ensure high-strength transmission.

Material Selection

Anchor chain wheels need to withstand high tensile forces, impacts, and seawater corrosion. Common materials include:

• Ductile Cast Iron (e.g., QT450-10 or ASTM A536 65-45-12):
  • Advantages: Good toughness, impact resistance, excellent casting performance, suitable for complex shapes.
  • Widely used for anchor chain wheels of medium-sized ships.
• Cast Steel (e.g., ZG230-450 or ASTM A27 65-35):
  • Advantages: High strength (tensile strength ≥450 MPa), suitable for large ships or high load scenarios.
  • Better wear resistance and fatigue resistance than cast iron.
• Stainless Steel (e.g., 316L):
  • Advantages: Excellent corrosion resistance, suitable for long-term exposure to seawater environments.
  • Higher cost, mostly used for high-end ships or special purposes.
• Surface Treatment: Regardless of the material, anchor chain wheels usually need hot-dip galvanizing or coating with epoxy resin (thickness ≥300μm) for corrosion protection. Some surfaces are quenched (HRC45~55) to improve wear resistance.