The design and structure of marine mooring winches are critical for ensuring the safe and efficient mooring of vessels in various maritime applications. Here's an overview of the key aspects of their design and structure: drum design, control the braking device, drum brake device, control device, clutch, warping head/drum, spooling device, fiber rope traction device, etc.

1. Drum design

When designing the drum, round-stranded steel wire ropes with tensile strength of 1520N/mm2 and 1667N/mm2 (6x24, 6x37) can be used.

The drum can also use synthetic fibres or other types of ropes.

1.2 The diameter of the drum should meet the following requirements:

a. Using round strand steel wire rope: the diameter of the drum should not be less than 16 times the designed diameter of the rope;

b. Using polyester or polyamide ropes: the diameter of the drum should not be less than 6 times the design rope;

c. Using polypropylene rope: The diameter of the drum should not be less than 4 times the design rope diameter.

1.3 The length of the drum should meet the following requirements:

a. The length of the drum with normal capacity should be able to wrap the entire length of the designed rope without exceeding 5 layers;

b. The length of the large capacity drum should be able to wrap the entire length of the designed rope without exceeding 8 layers;

c. To extend the service life of the rope, when the rope wound on the drum exceeds 4 layers, no heavy load should be applied. It is recommended to use a double-section drum, and the number of layers of the rope on the storage rope can be increased.

1.4 The drum capacity can be divided into two types: normal and large. The minimum length of the designed rope for storing normal capacity drums is 180m. The length of the rope stored on a large capacity drum should be twice that of a normal capacity drum.

1.5 The height of the drum flange should meet the following requirements:

a. When all the ropes are wound on a normal capacity drum, the height of the flange beyond the outer rope should not be less than 1.5 times the diameter of the rope;

b. The large drum should be designed so that the outer rope cannot exceed the flange height when all the ropes are stored on the drum. When designing, the ropes of each layer should be stacked vertically on top of each other, and no half of the rope diameter should be offset between two adjacent layers.

2. Control the braking device

The electric mooring winch must be equipped with an automatic control braking device. When the control handle or handwheel is moved to the stop or braking position or the winch has no power, the control braking device should automatically activate the braking function. The braking device must withstand 1.5 times the drum load and stop the drum rotation at maximum speed without failure. For other driving forms of winches, the design and ordering parties shall agree to use suitable braking devices, which should also be able to withstand 1.5 times the drum load.

3. Drum brake device

Each winch should be equipped with a drum brake device and be able to withstand the specified supporting load (the supporting load should not be less than 80% of the designed rope-breaking load).

4. Control device

The direction of movement of the control device must be marked with a permanent symbol. When the handwheel is turned clockwise or the handle is pulled towards the operator, it is considered to retract the rope, and vice versa, it is considered to release the rope.

Unless otherwise agreed between the subscriber and relevant departments, regardless of the power used, when manually controlled, the control handle should be able to automatically return to the braking or stopping position.

5. Clutch

In mooring winches equipped with cable reels or double drums, a clutch should be installed between the driving device and the drum.

6. Warping head/drum

The winch can be equipped with or without a cable reel, and the shape of the cable reel should meet the requirements of GB7390. The diameter of the cable reel should comply with the provisions of Article 1.2.

7. Spooling device

If requested by the ordering party, an automatic rope arrangement mechanism can be installed on the winch.

8. Fiber rope traction device

If requested by the ordering party, the winch can be equipped with a fibre rope traction device.

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