General structure and basic parameters of maritime anchor winches:

The general structure of a maritime anchor winch includes an electric motor and control equipment, mechanical transmission components, gearbox, star-shaped chain drum, wire drum, clutch, mechanical chain anchor brake, and anchor.

According to the mechanical structure of the ship, anchor winches are divided into two types: vertical axis winches and horizontal axis winches. On cargo ships, the bow anchor winches are horizontal axis winches. They are designed to perform two functions simultaneously: hoisting and releasing the anchor when fixing the ship at anchor points or hoisting and releasing mooring lines when maneuvering.

Most vertical axis winches, motor, and gearbox are located below the deck. This type of winch is used to hoist and release mooring lines during ship movements. Vertical axis winches are usually placed behind the bridge or on the two sides of large vessels for ease of line handling.

The basic parameters of the maritime anchor winch system include:

1. Towing force; speed of anchoring and line hauling; time of line hauling. The time of line hauling depends on the length of the anchor chain and the speed of line hauling.

To calculate the continuous towing force of the anchor winch (PC), the following assumptions are considered:

• The anchor is the standard type without stops.
• Wind pressure corresponding to Beaufort force 6.
• Water flow rate is 3 nautical miles per hour.
• Anchor depth is 100m.

The continuous towing force of the anchor winch includes the effects of buoyancy and anchor pipe. The effect of the anchor pipe is taken as 70%.

Only one anchor is hauled up at a time.

Due to buoyancy, the assumed mass of the chain link will be smaller than the specified value and is calculated per linear meter, kg/m, with d as the diameter of the anchor chain, mm.

The continuous towing force of the anchor winch (PC) is calculated according to the following table:

Material of chain link construction Continuous towing force of the anchor winch (kN) Ordinary steel PC = 0.0375d2 High-strength steel PC = 0.0425d2 Very high-strength steel PC = 0.0475d2

Basic requirements for the maritime anchor winch system:

The anchor winch must have the ability to withstand temporary overloads necessary due to sudden anchor breakage.

The anchor winch must be placed in a suitable position to ensure easy guidance of the anchor chain through the anchor pipe. The area of the deck where the anchor winch is located must be appropriately reinforced.

The anchor winch must be able to operate under all weather conditions and sea conditions.

The winch brake must have sufficient capacity to stop the anchor and chain when releasing the chain in a safe manner, even if the anchor winch loses power. If the anchor winch is not operated by steam, a one-way valve must also be installed.

A winch with brakes and equipped with chain hauling must be able to withstand a pulling force of 45% of the breaking pulling force of the chain without any fixed deformation of the load-bearing parts or slippage of the brake.

In addition to the brake, the anchor system is also equipped with chain stoppers. If the chain stopper is installed, it must withstand an 80% pulling force of the breaking pulling force of the chain. If not, the hauling winch must be able to withstand 80% of the breaking pulling force of the chain without any fixed deformation of the load-bearing parts or slippage of the brake.