We would like to share about ‘’Anchor chain tangled’’ experience.
When we let go the anchor without experience, then when we heaving up, the anchor chain may tangle on the anchor as below picture:
To avoid this situation, please take care of anchor chain condition and keep the vessel has sternway during letting go the anchor. Keep the anchor chain lay on the seabed properly.
ANCHORING OPERATION
DROP ANCHOR
The anchor cable should be veered step by step by using the brake ON-OFF at every half shackle to control the veering speed of cable. If the cable is veered rapidly, it has a possibility of causing an abnormal wear down and heating on brake lining, and such uncontrollable brake could lead to a serious human injury by the runaway cable.
(Though “at every half shackle” mentioned above, you should tighten the brake immediately in feeling like that upon untightening brake and starting drop anchor under bad weather condition, which would prevent abnormal wear down on brake lining.)
Anchor cable is to be secured by cable stopper without fail after dropping anchor or while the brake being effective since it is insufficient to hold power for anchor & cable with only the brake force itself.
(Pay utmost attention to safety when engaged in the work of setting the anchor cable stopper under bad weather.)
//SUPPLEMENT//
In general manner, the crutch to be disconnected to make it free from hydraulic motor once the anchor is lowered till the above surface of sea and the brake is tightened, and the anchor to be lowered into water by untightening the brake. In a meantime, it is observed sometimes that crew veer anchor cable by using hydraulic motor under rough sea condition. But all crews must understand that any damage on hydraulic motor resulted from using the motor is not compensated by maker because the operation with this hydraulic motor depends on the crew’s judgement. As rolling and pitching affected by wave or current under rough sea condition, it is fact that ship’s body, anchor and cable in water resistance could bring an excessive working load to windlass instantaneously, and the excessive load in water is huge and has wide range of fluctuation. Generally, a counter balance valve which controls veering speed is equipped with the hydraulic motor. But it is also not sufficient to protect the motor from such huge working load on the windlass. As a consequence, the dropping anchor is to be done by untightening the brake without connecting the crutch.
HEAVING UP ANCHOR
Once the anchor appears on sea surface, the anchor to be heaved up slowly less than 3m/min by checking the anchor position in order to avoid hitting against ship’s body. In rough sea condition, the machinery parts of hydraulic system could get damage due to excessive load being brought to the windlass. In order to avoid such situation, you are instructed to keep slack with anchor cable by using M/E driving force when heaving up anchor in rough sea.
In the event of a stoppage of heaving up anchor due to over load on the motor, you should cope with it by veering the cable a bit to make it slack.
//SUPPLEMENT//
Even though a safety release valve is equipped with the hydraulic motor for heaving up anchor, it still has a possibility of breakage of inner parts when an excessive load over the capacity of safety valve is brought to the motor instantaneously. “HEAVING UP ANCHOR” is rather capable of withstanding with the capacity than “VEERING ANCHOR”, but it has a limitation. It is required to be aware of the possibility of damage to the motor all the time.
HOW TO HEAVE UP ANCHOR UNDER ROUGH SEA??
The height of the waves should be dependent on the distance wind blowing through and period wind blowing continuously. Once the growing waves and the up-down pitching largely at ship’s bow is identified, C/Officer and Bos’n is to attend duty watch in forecastle to monitor the anchor condition. Especially it is important for watch crews attending in forecastle to make a clear report to bridge how the situation is developing in the night time. The waves which give an excessive impact to ship’s hull and anchor cable is composed of the height, the period and the direction, which is quite irregular. Under such circumstances, however, you are required to be aware of not only whether or not own vessel’s dragging anchor but also another vessel’s dragging anchor in the vicinity. Furthermore, once you recognize any situation of consecutive heavy up-down pitching for forecastle it is required to take an immediate action to avoid an impact of straightforward waves to ship’s bow by adjusting ship’s direction about 15 degree against anchor veering direction and to try to heave up anchor by loosening the tension of anchor cable as much as possible. If you see big waves under working of heaving up anchor, you should return the handle bar to stop position immediately and tighten the brake band simultaneously. It is already late to react so at the time waves reach the bow which would result in an excessive impact to hull. This brake handling should be done by 2 crews. Even though you might be able to heave up anchor only about 50cm – 1m within such a limited short moment, it is rather important to avoid excessive load to the hydraulic motor by using it. Though it is true that the brake lining might get an abnormal wear through this job consequently, it is still better considering the breakage of the motor.
PREVENTIVE ACTION FOR DRAGGING ANCHOR
In recent years we experienced some sufferings caused by affection of glowing low pressure becoming bigger than our expectation in the region of Japan and Korea, and which is called “Bomb cyclone”. If you have any waiting schedule in anchorage where it is likely that such a low pressure would affect, you are required to discuss with operator / owner or the local agent beforehand whether you should keep drifting at outside port.
The preventive action for dragging anchor asf;
1) Ballasting water
2) Main Engine Stand-by
3) Additional dropping anchor
4) Anchor cable extension
In moderate sea condition: 3D + 90m
In rough sea condition: 4D + 145m (D= sea depth)
Example: how many shackles are required to veer the cable in sea depth 15m?? (Answer: 7 shackles)
5) Use a steering
6) Use a thruster
7) Relocate the anchoring
8) Evacuating to area where the drifting is safe
The judgement should be given by Master in a view of weather forecast to protect life, ship’s property and shipper’s cargo and the prior notice should be made to all related parties at early stage before shifting to drifting position.
It is fact that most accident has resulted from both an error of judgement given by Master that it would withstand with anchoring there and the lack of mind for sharp looking or delayed reaction against the other vessel in the vicinity approaching to own vessel.
9) Giving an alert to other vicinal vessels via VHF
You shall check that the ship’s name, laden/ballast, bow direction and the distance to another vessel which drops anchor at the anchorage later than own vessel. In the light of sea condition including wind direction and wind force, it is required to request a re-anchoring to the other vessel in the vicinity as necessary. If any vessel approaches to your vessel for the reason of dragging anchor, you should illuminate the search light against the vessel.
10) Increase the number of duty watch crew
11) Install a safety rope on weather deck. Water-proof flash light and whistle to be in hand in spite of the working in day time. Transceivers to be wrapped with plastic cover to protect from wet damage. Safety belt to be put on as well. The duty watch crews who are engaged in the work at forecastle would get suffering from rain, wind and waves, thus a proper measure to be taken to protect own body.
12) In case of existence of serious problem to the machineries or ship’s hull, we can’t help but abandoning the anchor by cutting the cable at the final decision. Under such circumstances, you should liaise with company closely, and be aware of the dropping position by connecting a rope & a buoy at the endo of the anchor cable.
******************** The accident records of dragging anchor in the past *********************
Wind force 7, the dragging distance 800mtr for 10 min, dragging ave. speed 2.7knot (Grounding)
Wind force 8, the dragging distance 1000mtr for 15 min, dragging ave. speed 2.2knot (Grounding)
Wind force 7, the dragging distance 300mtr for 5 min, dragging ave. speed 2knot (Grounding)
Wind force 7, the dragging distance 200mtr for 2 min, dragging ave. speed 3.3knot (Collision)
Wind force 7, the dragging distance 500mtr for 5 min, dragging ave. speed 3.3knot (Collision)
Wind force 6, the dragging distance 300mtr for 5 min, dragging ave. speed 2knot (Collision)
Wind force 10, the dragging distance 500mtr for 5 min, dragging ave, speed 3.3knot (Collision)
Wind force 6, the dragging distance 300mtr for 5 min, dragging ave. speed 2knot (Collision)
Wind force 6, the dragging distance 325mtr for 7 min, dragging ave, speed 1.6knot (Collision)
Wind force 8, the dragging distance 560mtr for 11 min, dragging ave, speed 1.7knot (Collision)
Wind force 9, the dragging distance 925mtr for 15 min, dragging ave, speed 2.1knot (Collision)
Wind force 10, the dragging distance 500mtr for 5 min, dragging ave, speed 3.3knot (Collision)
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