How Long Are Anchor Chains on Cargo Ships?

The length of anchor chains on cargo ships can vary significantly based on the size of the vessel and its intended use. Generally, the length of an anchor chain is approximately 5 to 7 times the depth of the water in which the ship is expected to anchor. For large cargo ships, the total length of anchor chain can range from 200 to 400 meters (about 650 to 1300 feet), with some vessels having even longer chains. The chain is typically made up of heavy steel links designed to provide holding power and resistance to wear.

Factors Affecting Anchor Chain Length

Every ship is given an Equipment Number (EN) based on several key dimensions. These include the moulded displacement in tonnes to the Summer Load Waterline, the moulded breadth in meters, and the effective height in meters from the Summer Load Waterline to the top of the uppermost house for the lowest tier. The height is measured at the centerline from the upper deck or from a notional deck line where there is local discontinuity in the upper deck.

Equipment Number (EN) Specifications

Based on the EN, the number of anchors, their weight, the length of cable, and the size of cable are specified. The table provides details on these specifications, with Column 4 indicating the total length of cable required to be carried, divided between the port and stbd anchors. This length is in multiples of 27.5 meters, which is the length of one shackle or shot, depending on whether you speak English or American. For example, a ship with an EN of 205 would carry 3 anchors (2 main and 1 spare), with the spare anchor weighing 660 kgs. The total cable length required would be 302.5 meters, or 11 shackles of 26 mm mild steel cable. This 11 shackles would be divided into 56 parts.

Anchor Chain Specifications and Requirements

Ships are required to carry anchor chains of specific lengths and with certain specifications. These requirements are minimum and ships can often carry heavier anchors and more cable if they desire. A ship with an EN of 205 would need 3 anchors, 2 main and 1 spare, with the total length of cable required being 302.5 meters, or 11 shackles of 26 mm mild steel cable. The 11 shackles would be divided into 56 parts.

However, at the upper end of the scale, no ship is required to carry more than 770 meters (28 shackles) of cable, which is a maximum requirement. This ensures that ships are not overburdened with unnecessary equipment, while still providing a safe anchoring solution.

Conclusion

The length of anchor chains on cargo ships is a critical aspect of maritime safety and navigation. These chains play a crucial role in ensuring a ship can safely anchor in various conditions. It is important for ship owners and operators to adhere to the specifications and minimum requirements set by maritime regulations to ensure the safety and efficiency of their vessels.