The shipping industry at large experience increased focus on hull integrity – both as a measure of safe trade as well as of cost-effective trade. Continuous control of a ship’s hull condition creates business advantages to ship operators and owners. It affects the charterer´s preferences, the maintenance costs, the risk of accidents, and compliance with regulations, which in turn may contribute to a positive bottom line in the short and long term.
With DNV’s unique hull expertise combined with new easy-to-use Nauticus tools, DNV can help ship operators and owners take advantage of these benefits.
Over the past five years, DNV has assisted a number of owners in establishing systematics for planned inspection and maintenance schemes. Through DNV’s new total concept for Hull Integrity Management, this knowledge is efficiently shared and made available to all ship operators, utilising these main service elements:
Knowledge – Hull Competence courses,focusing on basic strength, structural defects and tank inspection for ship officers and superintendents
Systematics – Ship-specific Hull Inspection Manuals with unique 3D illustrations which identify what to look for during inspections and how to report it
Tools – Nauticus Hull Integrity software, easy-to-use and with unique 3D technology (previously HULC)
Support – Hull Advisory Services
Nauticus Hull Integrity, a web application developed by DNV Software, allows ship operators to efficiently and effectively manage their hull integrity. DNV Software and DNV Maritime have ensured that best practices in Planned Inspection and Maintenance Systematics are implemented into the software, supporting planning, inspections, analysis of the hull condition, organising management functions, and structured follow-up of work orders and repair specifications. The tool utilises the ship-specific Nauticus 3D technology for unique visualisation of the hull condition.
All the Hull Integrity Management service elements are developed with a practical approach to ensure understanding and user-friendliness, and to cover the ship operators’ needs. A number of large ship operators are already benefiting from the total Hull Integrity Management program described in depth in this article.
1. Hull Competence courses
Many shipowners have expressed a need for more expertise in the area of hull structural behaviour within their organisations. DNV has developed Hull Competence courses for various ship types to assist in filling this need.
The hull structure course gives the participants increased understanding of the structural configuration and response of ship structures. The course includes easy-to-understand illustrations and animations of how the strength responses of a ship act as a beam subject to different loads and end fixations. The course also goes into failure modes such as corrosion, cracks, buckling and indents.
Since the introduction of the ISM Code, requirements have been applied to shipowners of carrying out regular inspections of ships’ hull and equipment. The crew is often responsible for carrying out such inspections. Naturally, the quality of any inspection scheme is highly dependent on the qualifications of the inspectors. DNV has therefore developed a tailored, practical tank inspections course. The course objective is to develop participants’ capability to carry out safe and efficient hull inspections, and to document the results in a suitable manner.
2. Ship-specific Hull Inspection Manuals
Apart from structural expertise, systematic hull inspection and maintenance is essential to manage the hull integrity in a satisfactory manner. DNV’s Hull Inspection Manuals provide best-practice systematics for planned inspections and maintenance of the hull, and have already been adopted by several major shipowners.
The Hull Inspection Manuals utilise DNV’s hull knowledge base, and are a practical and comprehensive source of information for the crew and superintendents. The manuals are tailor-made for each ship design. They are developed in close cooperation with ship managers, and incorporate the ship managers’ maintenance standards and work processes for hull inspections and maintenance.
Key elements of a Hull Inspection Manual are the identification and listing of areas in need of special attention. To clearly illustrate these areas, DNV uses the Nauticus 3D graphical models as a visual platform supplemented by drawings or photographs. This provides a unique graphical description of areas requiring attention during inspections. This supports crew and superintendents in identifying potential damage at an early stage, hence minimising the risk for incidents and potential off-hire.
3. Nauticus Hull Integrity
The hull inspection is not complete until the findings have been properly recorded. To recapture the value of time and knowledge invested in inspection activities, the findings should be used by both crew and onshore staff to control the condition of the vessel or fleet. To help capture this value in a structured, consistent and effective way, DNV offers the innovative maintenance support system – Nauticus Hull Integrity.
With Nauticus Hull Integrity, the crew takes advantage of graphical navigation aids supporting the inspection process. Inspections are carried out using predefined inspection data sheets which are structured in the same manner as the ship-specific Hull Inspection Manuals, ensuring transparent information capture which will help maximise reuse of the valuable findings. The crew’s inspection work process is supported by automatic transfer of inspection recordings to their central database onshore.
The onshore technical staff uses Nauticus Hull Integrity to analyse and document the vessel or fleet condition, and to prepare for repairs and dockings. An immediate condition control is enabled by colour-coded severity alarms displayed graphically on 2D tank plans and on 3D models for individual tanks. This facilitates a proactive maintenance environment where decision support is provided to superintendents and fleet managers, allowing them to quickly take action based on thorough and consistent ship and fleet condition data.
Experience so far has proved that the software is intuitive and easy to use, requiring only a minimum of training. Combined with training in hull structure and tank inspection, and the Hull Inspection Manuals, DNV offers a very powerful total concept enabling shipowners and operators to efficiently and effectively manage their hull integrity.
4. Hull Advisory Services
DNV offers specialised Hull Advisory Services to support hull integrity management. These services are based on DNV’s extensive hull knowledge base and sophisticated tools for structural assessment using a comprehensive 3D graphical model of the vessel. The services include:
- Steel renewal estimation and specifications
- Coating renewal estimation and specifications
- Docking specification and planning
- Emergency repair specifications
- Thickness measurements (UTM) guidelines, processing and maintenance planning
- Feasibility of conversions from single to double hull.
Better control of the coating condition and steel diminution avoids corrosion on a big scale and contributes to the overall safety, as well as to cost efficiency. Following an incident, assistance with planning of repair activities can reduce off-hire time and costs. Experience with these services over many years clearly demonstrate that onshore and onboard crew achieve much improved communication of the hull condition by utilising the Nauticus 3D technology.