What chance for wind?
Periodically new attempts are made to promote efforts to find new ways to employ wind power on ships as a means of achieving savings and preventing pollution. Despite a prolonged period of high fuel prices, few if any have gained traction but efforts to promote them do not seem to stop coming. Perhaps the most promising has been Norsepower’s Rotor sail installed on Bore’s Estraden. Combining the Flettner rotor effect with windpower, the device is claimed to have returned a 2.6% fuel saving. As a retrofit to an existing vessel there is at least some data to compare the claims with by way of past consumption data. Generally though all attempts to employ wind have failed and a new study released this week by UCL and the CWR attempts to explore the reasons why. There are several reasons why wind powered ships have not been part of shipping for almost a century but the most compelling is that it has simply been eclipsed by modern technology. Wind power was perfected over a period of thousands of years and in favourable circumstances performed well. Certainly records show that some voyages were made at comparable or better speeds than are achievable today. But those are the peaks of achievement and nobody has bothered to look lower down the scale where ships were becalmed for days or weeks at a time, damaged by high winds and frequently lost when driven on to rocks. Even the least efficient steam or motor vessel could counter the worst effects of wind. Shipowners are not stupid and the economic case of replacing sail with an engine was not one of fewer crew needed or lower cost because in most cases the number of stokers and the cost of the engine were higher than deckhands and sails. The fact was that ships became more reliable and allowed the establishment of liner services running to set schedules. Flettner rotors and sails may suit some ship types but they would hardly be practical on a modern container ship where most of the cargo is on deck. Nor would they be so easy to install on bulkers or tankers without taking up valuable space, adding weight, adding a maintenance cost and having a capital cost so that when all are combined might well offset the effect of any fuel saving achieved. Shipowners will examine closely any fuel saving technology, that some might be rejected is more a case of it not being practical and fitting with operational needs than owners not wanting their ships to be guinea pigs.