The earliest stages of design are essential for cruise safety By Esa Henttinen, Executive Vice President, NAPA
he passenger ship sector—particularly the cruise shipping business—has the strictest safety requirements in terms of operation and design of any sector in the shipping industry. Consumers place a huge amount of trust in cruise shipping companies. If those companies have one misstep, the consequences can be severe—in terms of human life, in terms of assets, and in terms of reputation. When there is a safety incident aboard one cruise ship the reputational damage extends beyond the ship, beyond the company, and to the scrutiny of the entire industry. It may be a highly competitive industry, but safety brings all the stakeholders together to find advanced solutions, to set standards, and share best practices.
Complex Cruise Ships, Complex Calculations Safety starts at the critical first stage of design for a cruise ship. One of the tools that naval architects use is NAPA. Every purposebuilt cruise vessel in operation today was designed in initial stages using NAPA software. NAPA tools help naval architects create the
structural design and initial layout for the vessel in a fully equipped 3D CAD model. Based on the model, the system is capable of making the complex calculations required for compliance with IMO standards on strength and stability. Many of these calculations would be impossible to do manually, including, Index R requirements. Index R represents the damage stability of the vessel – its ability to remain stable and afloat in the event of flooding caused by collision. Index R, if calculated for a container ship would be a relatively simple process, achievable in a simple spreadsheet. However, today’s generation of cruise ships have complex geometry; thousands of passenger cabins and spaces, over 100 liquid tanks, staircases, numerous elevator shafts. This makes estimating how flooding may progress a much more complex operation. NAPA’s 3D model automates these calculations in only a few minutes and can recalculate it or any other mandatory calculation whenever the design is adjusted, which can be done at any time. This flexibility is also a critical aspect of the system, if the designer runs initial calculations and wishes to increase the margin of safety September 2017 // Marine Log 33