Demystifying Ship Recycling - Issue 10

09 Feb 2021
Author: Mr. Kiran Thorat & Dr. Anand Hiremath

Stability of vessel’s hull during recycling at HKC Compliant recycling facilities. 

Ships are designed and constructed considering intact stability and damage stability. Vessels during their active sea service remain stable while facing rough seas and different adverse weather conditions. Ship’s stability is achieved during sea life by using seawater for ballast and laden passage. Occasionally in older vessels, sand, mud, or pig iron was used as permanent ballast. Ships usually remain stable unless some operational errors occur in ballasting and deballasting operations or following improper loading and unloading sequences. 

Stability-of-vessel-hull-during-recycling-at-HKC-Compliant-recycling-facilities


When a ship is delivered for recycling to the HKC compliant yards, her hull rests on the ground. The stability criteria for ships are different than in the afloat condition. At first, a ship-specific Ship Recycling Plan (SRP) is prepared. In the SRP, a sequence is incorporated to slice the vessel’s hull basis estimated weights by naval architects. Accordingly, the slices are removed from the port and starboard side of the hull to ensure the center of gravity of the hull remains within the hull, and the ship remains upright all the time. The hull is cut in a Zig-Zag way to ensure that nearly the same weight of steel plate sections are removed from both sides of the vessel’s hull. Cutting hull in this pattern helps to maintain safe access to the vessel’s structures, and effective working height is reduced. It takes roughly 6 to 8 months to cut the complete hull at a normal recycling rate in which the ground conditions change. The hull is pulled towards the recycling yard regularly as recycling progresses. Therefore, the cutting sequence is altered in some instances to ensure stability with prior approval from the SRP committee. Furthermore, the hull is secured with heavy-duty chains to the winches. The slices are lifted with cranes with heavy lifting capacity and kept on the secondary cutting zone without allowing them to fall on the intertidal zone.

HKC compliant recycling facilities have developed SOPs to ensure recycling is done safely and environmentally soundly. 

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About Author

Kiran Thorat is a Sustainable Ship & Offshore Recycling Executive at GMS, where he looks after sustainable ship recycling projects. Kiran believes that Sustainable Recycling is an integral part of Sustainable Shipping and a notable example of a circular economy. He holds a Bachelor's Degree from Marine Engineering and Research Institute (DMET), India, and a Master's Degree in Energy, Trade, and Finance from Cass Business School, London.

Dr. Anand M. Hiremath is a Civil Engineer and holds a Master's Degree in Environmental Engineering from the Indian Institute of Technology Guwahati (IIT Guwahati), India. He was awarded Doctorate Degree in the year 2016 for his research work on Ship Recycling by the Indian Institute of Technology Bombay (IIT Bombay), India. In addition, he has a diploma in Industrial safety, is a qualified lead auditor for ISO 9k, 14k and 18k. Dr. Hiremath published the first practical handbook on ship recycling, entitled: "The Green Handbook: A Practical Checklist to Monitor the Safe and Environmentally Sound Recycling of Ships" which highlights the procedures the GMS RSRP follows to help both Ship and Yard Owners recycle a vessel in an environmentally-friendly manner.

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Ship Recycling Team