Back to sail—for oil tankers and cargo carriers?

Press, 20 July 1977, Page 19

Back to sail—for oil tankers and cargo carriers?

By

JOHN WILLIAMS

One of Britain’s leading yacht designers is to hold a revolutionary experiment in about six months time. The experiment will take place off the British coast, and will involve fitting sails to a large merchan ship — either a super-tanker or a large bulk cargo carrier. The plan is to convert

the ship partly to sail power, to save money on diesel fuel for its engines. If the experiment successfully proves that sails can be used on modern merchant vessels, more ships will be converted. The designer told me: “It is not a question of whether I think it likely that sail power will make

a come-back. It is simply that if this trial works, and the sails enable the ship to save fuel, then the idea will be taken up.”

To describe the experiment, and the detailed planning now taking place, as “top secret” would be to over-dramatise the position; but details are not being released because the preparations are incomplete. Even the name of the designer is being withheld. The demand, he says, “would push me along faster than I want to go.”

Between now and the next Northern Hemisphere winter, the feasibility of the idea will be tested and developed by use of scaled-down ships. Then will come the full-size trials out at sea — and perhaps the dawning of a new age of sail. Behind what sceptics might regard as the unlikely sight of large ships rigged up with sails, lie some hard economic facts; The cost of powering a 250,000-ton oil tanker for a year is about $3.2M. The new wind-power concept does not envisage

rigging them out with a full suit of sails in the manner of the old squareriggers or schooners. The idea is to erect some more modern design of sail whose push would augment the propulsion of the ship’s ordinary engines.

The yacht designer who is involved in the experiment has in mind a figure of 10 per cent. If his sails provided 10 per cent of the ship’s required power, then that annual fuel bill would come down from $3.2M to $2.88M. It is the juicy prospect of saving so much fuel that has prompted several ship owners to offer the loan of their vessels for the sail-power experiment.

The use of the term “sail” does not imply a slavish copying of old patterns. The modern concept of sails is much broader, and could range from the old schooner variety, through the lateen-rig of Arab dhows and the pecu-

liar shape of Chinese junks, to some form of

wind turbine which, like windmills on dry land, harness the force of the wind to turn some mechanism. On board ship the mechanism might generate electricity which would in turn be used to turn the propellers. The coming British experiment will be the first practical attempt to convert modern engine-pow-ered ships to wind-power.

Over the last few years there have been several theories. One of the most interesting was for tall aerofoil “sails” rather like a jumbo jet’s wing to be erected on a cargo ship’s

deck. An electronic computer would control their swivelling round their masts to catch the wind.

This design came from Professor W. Prolss, of Hamburg University. An aircraft designer, he died last year, and now an American firm is pursuing the idea. Tests with models in tanks and wind tunnels indicated that a 17,000-ton ship averaging 14 knots would be the most feasible size. Another line of research involves rotors of various sorts. They inelude a windmill type which has already been fitted to an experimental ship. The windmill was linked directly to the ship’s propeller.

There is also a composite rotor device with numerous smaller blades, all whizzing round with the wind and driving the ship’s propellers.

All the latest wind power shipping work is not concentrated on newstyle technology. A strong

body of opinion recognises that before steam power came along, the design of sailing ships had reached a satisfactory level of efficiency.

There are at least two projects underway to build a modern version of old sailers. One was aired at a sailing ship symposium organised by the Royal Institution of Naval Architects in London last year. Two Australian designers, Warwick Hood and Peter Warner, said they would operate a 2200-ton schooner as speedily and much more cheaply than an engine-powered ship on runs from the east coast of Australia, or the South Island of New Zealand, to Fiji and Tonga. Allowing for loading time, the round trip from New Zealand would take 30 days, and from Australia 32 days — one day longer than a motor ship, and with no fuel cost.—World Feature Services.