Anemoi Marine Technologies (Anemoi) and Nantong COSCO KHI Ship Engineering (NACKS) have developed new wind-assisted propulsion (WAPS) integration solutions for Ultramax bulk carriers as the vessel segment prepares for rapid fleet growth.
Two configurations designed to streamline installation and enhance fuel-saving potential of rotor sails on the 606,500 dwt vessels have been awarded an approval in principle (AiP) from Japanese classification society ClassNK.
The configurations fit a range of common operational requirements for Ultramax vessels. Both use the latest-generation rotor sail from Anemoi, with a sail size of 3.5m diameter and 24.5m in height, which is an increased area compared to Anemoi’s pilot installation on an Ultramax in 2018, designed for greater fuel savings. While one arrangement features one rotor sail, placed on the forecastle deck, the other uses a longitudinal rail system to deploy three sails on the upper deck.
Ultramax vessels have been early adopters of WAPS technology, going back to Anemoi’s installation on the first bulk carrier with rotor sails in 2018, the Afros. The AiP is said to represent an opportunity to apply this experience to optimise installations for maximum efficiency on our generation 3 products.
Nick Contopoulos, Anemoi CCO. said: “Working with COSCO-owned shipbuilder, NACKS, the project enables Anemoi to strengthen its collaboration and reach within Chinese yards. According to DNV, China now accounts for more than 25% of the bulk carrier newbuilds compared to 5% just a decade ago, with NACKS and the wider COSCO group contributing significant volumes.”
The AiP confirms the feasibility of the integration concept designs under ClassNK’s guidelines for WAPS. Factors considered under the approval include sail particulars and arrangement, foundation and supporting structures, initial trim and stability calculations, fire and safety arrangements and energy efficiency calculations under IMO’s EEDI framework.
Image: Anemoi rotor sails on Ultramax vessels (source: Anemoi)



