The encyclopedia · Engineering & Operations · Technical decision · 2018
Norsepower revived the 1924 Flettner rotor as a wind sail on a 2018 tanker
A spinning steel cylinder uses the Magnus effect to push a ship forward, cutting the Maersk Pelican's fuel 7-10%.
Norsepower · Maersk Tankers
the move
Anton Flettner installed his first rotor sails in 1924 on the converted schooner Buckau and it worked, but cheap fuel and the Great Depression killed adoption.
Nine decades later Norsepower built an updated Flettner rotor with automated controls and lightweight construction, and in 2018 installed two of them aboard the LR2 tanker Maersk Pelican — at 30 m tall and 5 m wide, its largest units yet.
The rotor sails add forward propulsion from the wind; in favorable conditions the main engines are throttled back, and Norsepower projected a 7-10% fuel and emissions cut. Lloyd's Register collected data for an independent assessment.
why it works
- The engine does the work only when the wind won't, so fuel savings come free of extra power.
- It uses proven Magnus-effect physics already validated in 1924.
- It retrofits onto existing ships with open deck space, so no new hull is needed.
- Energy agencies saw it as one of the few fuel-savers promising double-digit gains.
what transfers
Old ideas fail for economic reasons, not technical ones — reprice the energy and the rejected answer can become the cheap one.
what came after
The Maersk Pelican installation was supported by the Energy Technologies Institute, and Norsepower rotors also went onto the ferry Viking Grace and the ro-ro Estraden; the concept has since spread across tankers, bulkers and ferries.
references
- Two Wind-Power Rotor Sails Installed on LR2 Tanker
- What Is Old Is New – Norsepower Brings Back Wind Power to Commercial Shipping
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