Guidelines for Hull Condition Assessment Applicable to Single Skin Bulk Carriers on International Trade

Abstract

The poor safety record and innumerable accidents recorded on board of bulk carriers coupled with the type of cargoes and hardship that bulk carriers endure during its operational life; have triggered the maritime community to pay special attention to the design, construction and overall the scope and quality of the inspection of the bulk carriers in service. As it is widely known, due to several reasons, during the ship’s life of a bulk carrier, the vessel is affected by structural defects leading to deterioration of its condition. These structural defects may take the form of material wastage (corrosion), fractures or deformations, origin of which may be traced during the building stage to poor structural details, deficient materials, misalignment, welding defects and in-service stage to heavy cargos, environment, heavy weather, material wastage, collision, poor maintenance, improper loading/unloading operations, among others. In general, ship hull structure assessment is a process to determine the reliability of the existing structure in terms of carrying current and future loads and to fulfil its task for a given period. In this process, if paramount to be always clear of the assessments objectives and acceptance criteria. In the shipping world, there are two main objectives to conduct the hull assessment of existing ship hull structures, the assurance of structural safety and serviceability and the minimisation of costs and repair time.

Due to the great dimensions of the vessels nowadays, the dangers and difficulties to access the different ship structure of a bulk carrier make the classification and statutory inspections on board bulk carriers very challenging. Especially, when one takes into account the commercial pressure inherited in the maritime operations and that these inspections will last maximum one or two days and while the vessel is performing cargo operations. Being the only exemption when the inspection is carried out in conjunction with a dry-dock. The main objective of this thesis is to develop a documentation aide in the form of clear procedures and guidelines for hull condition assessment of single skin bulk carriers to be used by Overseas Marine Certification Services (OMCS CLASS) attending surveyors during their inspections. Overseas Marine Certification Services (OMCS CLASS) is a recognized organization, recognized security organization and classification society acting on behalf several flag states in order to survey, certify and classify vessels registered on those flags. These guidelines should assist the attending surveyors in conducting their inspections as informed as possible and making sensible decisions by focusing on structural areas that are most prone to failure or degradation. It includes a review of the survey history of ten (10) single skin bulk carriers classified by OMCS CLASS; which were randomly selected from a list of sixty (60) vessels provided by the company. The review consisted on verifying the class survey statements, transfer of class information, list of deficiencies or conditions of class related to the hull raised during that period, thickness measurement reports and finding, enhanced survey program survey reports and port state control detention records. As well, a review of the safety aspects related to the performance of the survey, the necessary access facilities, the preparation necessary before the surveys can be carried out and expose the different main hull structural areas where damages have been recorded, focusing on the main features of the structural items of each area.

Due that the information gathered during the internship was deemed to be confidential by the company and that the propose guidelines is to be of exclusive use of OMCS CLASS, the thesis is divided in two parts; a first part is made public and comprise of five sections on which a brief description of the propose guidelines is included and an appendix no. 1 on which the complete propose guidelines is included on OMCS CLASS letter head ready for their review and hopefully future exclusive use. On the appendix no. 2 of this thesis, the different existing forms of OMCS CLASS for the survey program questionnaire, program and the reporting format that were reviewed and updated are included.

These guidelines encompass and summarize the different requirements, recommendations and guidelines found on IMO Resolution A.798 (19), A.866(20), A.1049(27), A.1104(29), and IACS Unified Requirements Z7, Z10.5, Z11, and IACS Recommendations 46, 47 and 87, IACS Harmonized Common Structural Rules for Bulk Carriers, and IMO MSC.1/Circ.1502 among others.