Power and automation technology group ABB says it has modified its Azipod propulsion unit frame design to improve hydrodynamic efficiency by more than two per cent.
The improvements are the result of an optimized Azipod fin shape and a new pod cap structure, called Xtail. The new fin structure receives water flow from the propeller at a less acute angle than the previous one, and the curved design redirects the flow more efficiently. The X-tail straightens the flow of water on ejection from the Azipod propulsor, minimising swirling.
Royal Caribbean International’s Radiance of the Seas became the first cruise ship to instal the modifications during a drydock in summer 2011. According to Azipod, the vessel’s subsequent sailings from May to September demonstrated a two per cent improvement in hydrodynamic efficiency compared to a sister vessel and the ship’s own previous operating record. The new features will now be included in new Azipod XO units and can be refitted to existing vessels equipped with older Azipod VO and XO units.
“The fuel efficiency improvements measured on Radiance of the Seas are a welcome reprieve in today’s higher fuel prices,” said Anders Aasen, associate vice president of technical services for Royal Caribbean International and Azamara Cruises. “Any improvements we can make on fuel efficiency will serve us well for future operational costs.”
Tomi Veikonheimo, chief hydrodynamist at ABB Marine, remarked: “Azipod propulsion has been in the market about 20 years and a lot of hydrodynamic improvements have been made during that time. However, from the hydrodynamic point of view the system still has a lot of potential. More new ideas will be studied, tested and applied to improve ship fuel efficiency.”