Fig. 4 CRP Azipod RoPax machinery
When comparing the shipyard construction costs of the two alternatives, it could be seen that the CRP Azipod option is 2% (2 MUSD) more expensive which converts into an annual additional cost of approximately $150,000. This comparison takes into account the cost of procuring the individual components as well as the installation costs of the whole system.
The final outcome of this study was that the CRP Azipod alternative required a 4,5% lower ticket rate that the mechanical twin shaftline alternative.
In addition to this clear economical advantage, the study identified the following advantages:
・ The machinery weight was reduced by 6.5%
・ Nitrogen oxide (NOx) emissions were reduced by 12%
・ Sulfur oxide (SOx) emissions were also reduced by 12%
・ CO2 12% less than conventional ship
・ The maneuverability of the vessel was improved.
5. CONCLUSIONS
Recent experiences with the diesel-electric power plant concept combined with the Azipod propulsion system have proven the concept to be an attractive solution for various types of vessels. The improved total efficiency, enhanced maneuverability, redundancy, simplicity and proven reliability of the design, can be utilized in various ship projects. The suitability of the concept for cruise ships is obvious, which the successful sea-trials of the M/S Elation prove. Other ship types such as RO-RO vessels and offshore supply and support vessels are a potential market as well as all other typically dynamic positioning ships.
The feasibility analysis for a new project should always be carried out together with the shipbuilder. The Azipod propulsion concept changes not only the way ships can be designed and operated but also how they are built.
The above summarized concept study clearly showed that the Contra Rotating Azipod concept was the most feasible solution, providing a more capable vessel at a lower total cost. The concept clearly shows high potential for a variety of vessels and operation profiles. The success of the concept naturally requires experience of different installations and thorough studies and testing of areas such as hydrodynamics, electrical network configuration and development of building processes from the shipyard point of view. As in all new technical concepts and innovations in the shipbuilding market, shipowners and shipyards must accept and see the benefits to be ready to implement them.
References
Concept study "Fast RoPax Vessel with Azipod Propulsion", Kvaerner Masa-Yards Technology, 1999.
