Live long and prosper!

In answer to this question, Ben Hodgson, project manager at BMT, maintains that the part EU-funded FLAGSHIP hull condition assessment (HCA) project has successfully developed a system for extending a vessel’s life by up to five years, with a 10% to 20% reduction in repair costs.

Although traditional inspection regimes work well in terms of assessing a ship’s current condition, each inspection is a snapshot of a vessel’s condition which provides little feedback as to possible issues in the future. FLAGSHIP’s-HCA sub-project has developed a framework and methodology designed to encourage the recording of survey data in a way that can be utilised to focus future inspections and extend the service life of vessels.

FLAGSHIP is a consortium of more than 40 European maritime organisations focused on improving the safety, environmental friendliness and competitiveness of European maritime transport. The FLAGSHIP–HCA sub-project was led by the BMT Group in the UK and supported, delivered and trialled in conjunction with MARINTEK, BV, GL, Sirehna and PORTLINE – Transportes Marítimos Internacionais.

In order to provide a baseline for all the survey data, the team developed a methodology utilising a digital model of the ship’s structural elements sourced either from the vessel’s original construction drawings or a computer aided design (CAD) 3d model. To prove the concept and ensure that the research was applicable to the real world, the team was given access to the Supramax bulk carrier Angela while she was in dry dock. The vessel’s plans were used to create the first 3d model and maintenance and survey data taken.

To allow the surveyor to interact with the 3d digital model, FLAGSHIP-HCA used a software package called the ‘survey advisor tool’ (SAT) which provides a user friendly interface displaying 3d drawings of the vessel with the option to select individual elements that have been identified for inspection.

The shipowner has access to a hull health assessment (HHA) tool with the same 3d interface as the SAT tool and with similar functionality. The HHA tool also allows the onshore and onboard crew to collect their own observations and information about repairs. In order to ensure ease of exchange of compatible information between the parties, the team used a file format called hull condition model (HCM). Each individual HCM file contains the 3d model of the ship and all the data used for condition assessment (coating condition, steel thicknesses, etc.) allowing interested parties to use their experience and provide input.

In the first iteration of the process, the survey data can be used to identify any maintenance that is required in the same way as a traditional inspection. Subsequent replacement, repainting or recoating will be recorded via the SAT to ensure an up to date record of the condition of the vessel.

Using the survey information, the FLAGSHIP-HCA software applies a mathematical model which predicts the rate at which a particular element will corrode based upon the sort of environmental conditions it’s exposed to. By applying the model to a whole vessel it is possible to identify which elements should be most closely inspected during the next survey.

Furthermore, as subsequent surveys are completed, it will be possible to fine-tune the corrosion model which means that the lifespan of a particular element can be accurately estimated and ensures that surveys, repair and maintenance is carried out at the most appropriate time. With access to projected rates of corrosion, ship owners and operators could manage and extend the working lives of their assets far more effectively.

Another value-add is that the HCM format makes it simple to share information about specific types of ship enabling a shipowner or operator to compare survey results from a fleet of ships of the same type in order to identify specific corrosion hotspots. Similarly, class societies could obtain large amounts of corrosion data from every ship which is under their jurisdiction and use this information to refine class rules and guidelines.

With the caveat that FLAGSHIP-HCA is a research project, the outcomes are extremely positive and have the potential for commercial exploitation. The benefits in terms of preventative maintenance and extension of asset life would certainly deliver return on investment.