Three types of methods
Vessel generally use any one of the following methods:

“Dropping” or “letting go” anchor from the hawse pipe of just above the water line. For depths up to 20m.

“Walking back” anchor just above the sea bed for depths between 20 to 50m.

“Paying out under power” for depths between 50 to 80m.

Anchoring in water of 20m or less depth by “Letting go from a cockbill position”

⦁ Engage the cable lifter unit to the winch and then insert the clutch locking pin if it is not a hydraulically operated clutch.
⦁ Rotate the shaft in heave direction to take up the slack in the transmission system.
⦁ Release the cable lifter brake.
⦁ Open the chain stopper dog/ guillotine bar.
⦁ Lower the chain till the anchor is at sea level.
⦁ Apply the cable lifter brake and disengage the cable unit from the anchor winch and insert locking pin.

⦁ Open and close the cable lifter brake, dropping the anchor in CONTROLLED STEPS, by releasing the brake from the cock-bill position, and an amount of cable approximately equal to twice the depth of water is first allowed to run out freely to enable the anchor to embed itself.
⦁ Absolutely avoid high speed during anchor drop.
⦁ If the cable is paid out too fast, it can result in the anchor & cable piling up on the bottom and lead to poor holding.
⦁ If the brake fades or fails there is a risk that the cable will run out to the bitter end, with consequent damage.
⦁ Thereafter, the windlass brake is applied so that the cable is kept growing at an angle of about 30 degrees to the vertical.

⦁ In large ships, sternway after letting go the anchor should be adjusted within 0.5 to 1.0 knot to prevent an excessive strain on the cable.
⦁ When the intended shackles of the cable are paid out, sufficient brake should be applied to cause the flukes of the anchor bite into the seabed.
⦁ When the cable becomes taut and then slack and continues to maintain minimum weight with a catenary, it is a sign that the ship is brought up. At the same time, the ship begins to turn towards the weather.
⦁ Close the chain stopper dog/ guillotine bar and insert the locking bolt and the securing pin if there is one.

Anchoring in water of 20 to 50 meters depth by “walking back close to bottom and letting go”

When anchoring in water of 20 to 50 meters depth, the free-fall anchoring from the cock-bill position may cause the cable to attain a dangerous speed as it runs out, the result being a parting of the entire cable. There is also risk that the anchor may fracture on striking the bottom at high speed.

To prevent such hazards, walk back the anchor into the water intil it reaches about 5m above the bottom.

The brake should then be secured and the windlass taken off the gear.

The anchor should be let go taking care that the vessel is moving astern such that the anchor cable will not pile up in a heap on the sea bottom.
The required scope of the anchor cable must be paid out. Care is to be exercised in controlling the paying out speed and master must ensure that vessel speed over ground is less than the paying out speed.

Increased vessel speed over the ground or uncontrolled paying out of the cable can cause the cable to be inadvertently paid out till the bitter end, thereby causing damage to the bitter end release arrangement, spurling pipe, windlass and finally to losing the anchor along with the cable.

Repeated applications of the brake after short lengths of cable have been paid out can keep the system under control and prevent excessive acceleration of the gypsy.

When the brakes are secured, the anchor digs into the seabed, preventing the vessel from moving any further astern over the ground.

Anchoring in water of 20 t0 50 meters depth by “walking back close to bottom and letting go”

The sternway is stopped by the action of the anchor as strain comes onto the chain. Then, due to catenary of the chain, the vessel moves forward and stops. The vessel is then described as being “brought up”

After anchoring and tightening the brakes the cable stopper must be used. Cable stoppers must be flush over a horizontal link and should be secured in position to prevent it from jumping under load.

Do not leave the windlass gear engaged. To provide an early warning of anchor cable slippage a flag may be used which must be visible from the bridge.
Most of the losses related to anchor have been attributed to too high speed over ground, too little cable being paid out during the walking back of the anchor prior to letting go or allowing too much chain to pay out when the brake is opened. The running speed of the chain is to be well controlled by proper/frequent use of the brake.

Anchoring in water of 50 meters to 80 meters depth (Deep anchoring) by “paying out under power”

When anchoring in water of 50 meters to 80 meters depth, the anchor and the amount of cable intended for use are paid out by the walk- back method all the way under power.

⦁ Approach the anchor position heading into the wind/tide.
⦁ Stope the ship over the ground.
⦁ Engage the cable lifter unit to the winch and insert the clutch locking pin.
⦁ Rotate the shaft in heave direction to take up the slack in the transmission system.
⦁ Release the cable lifter brake.
⦁ Open the chain stopper dog/ guillotine bar.
⦁ Lower the anchor by control of the winch motor in low speed only- apply the cable lifter brake at all stops.

Make sure the vessel is not drifting with a SOG higher than 0.3 knots astern. If required use the main engine to counteract.

The design maximum speed for the windlass to walk out the cable is typically 9meters/minute, which equates to less than 0.3 knots.

The windlass motor is the weakest link in the system and, if the windlass over-speeds, there is a risk that the motor will be damaged. On some hydraulic systems utilizing high speed, highly geared axial motors, damage could result in catastrophic failure and the risk of injury to personnel from flying debris.

Where possible, personnel should avoid standing directly in line with motor and, if fitted should make use of remote controls.

When the required chain length is paid out, apply the cable lifter brake, close the chain stopper dog/guillotine bar and inserting the locking bolt and the securing pin if there is one.

Disengage the cable lifter from the anchor winch and insert the clutch locking pin.

Securing the cable at Anchor

Cable secured on the brake with the chain stopper

It is recommended that where a chain stopper is fitted it is used. The stopper is designed to withstand 80% of the MBL of anchor chain, whereas a properly – adjusted windlass brake is designed to render at 45% MBL.

However, it should be noted that it may not be possible to release the chain stopper without using the windlass to relieve the force on the chain stopper.

In deteriorating environmental condition, cable tension will increase to the point at which the anchor drags or the weakest point in the anchor system fails.
This could be physical damage to the anchor, failure of cable or damage to the stopper. When subjected to extreme forces, the stopper may deform and jam in place, hampering quick recovery of the anchor.

Cable secured on the windlass brake

With this method, in deteriorating environmental conditions, cable tension will increase to the point at which the anchor drags, or to the point at which the windlass brakes holding capability is overcome, and the brake slips, whichever is lower.

A traditional method is to mark the cable so that it is visible from the bridge, for example, by a flag tied to the cable on the cable lifter/gypsy is used to detect the brake slipping.

Some vessels may be fitted with remote reading cable counters or other devices that detect any movement of the cable lifter/ gypsy wheel.

Whichever method is used to secure the cable, it is important to get underway before the tension in the cable increases to the point where it risks a failure of the anchor system and also exposing personnel to hazardous situation on the forecastle.