ROTOR SHIPS

Southland Times, Issue 19837, 7 April 1926, Page 5

ROTOR SHIPS

PROPOSED ATLANTIC VOYAGE. ONLY 25 TONS OF FUEL. London, April 4. The Tithes Hamburg correspondent states that the rotor-ship Badenhaden is taking in 25 tons of fuel preparatory to her first trans-Atlantic voyage, bound for New York. —Times Service. ONE FOR GERMAN NAVY. Berlin, April 4. A rotor-ship of 3000 tons is being built for the navy.—A. & N.Z. These reports will cause some surprise, as it was reported some months ago that the rotor-ship had proved a commercial failure. The Hamburg-America line has experimented with them a great deal, and m 1924 the correspondent of a London paper in Germany wrote —The report that the Hamburg-America line has decided to ordet a fleet of cargo ships on the Flettner principle has helped to sustain public interest. in the idea, and a better conception of the principle is going to be held by the shipping world. Broadly, the whole principle of the scheme is precisely the same as that which in aerodynamics is used io lift the aeroplane. By the shape of the wing the horizontal current of air which is created by the progress of the machine is given a “vortex motion,” which converts it into a vertical force at right angles to its original course. This is precisely what occurs in the case of the rotor ship, but instead of the somewhat elementary means of a shaped wing it is obtained by the rapidly revolving motion of the towers. As the direction of the towers can be altered it will be’ realised that this deflection of 90 degrees can be put to good use in driving the ship forward in any direction of the wind, while it utilises the force infinitely more efficiently than the ordinary sail or the windmill-pattern multiplier that was favoured by the French experiments which first drew attention to the possibilities of the whole principle of efficient wind-power. Professor Anton Flettner, the inventor, has won the opinion of shipping men by the eminently reasonable claims that he makes. He does not suggest that he is going to revolutionise the whole system of shipping by cutting fuel costs down to nothing and letting the winds of heaven do the work in a manner that they have never done before, but only that his scheme will be a very useful auxiliary to a fully powered cargo-carrier which will greatly reduce the cost of fuel. This puts it somewhat on a basis of the step from the compound to the triple-expansion steam engine —a step which was not revolutionary but which made all the difference to the shipping of the day. Such a step in economy at the present day would again mean all the difference to the industry. Practical sailormen can see many disadvantages in the invention. In a little 500ton schooner the towers are 60ft high and thick in proportion, so that in a big ocean cargo-carrier or a passenger liner they would be colossal. Such towers would mean that the cargocarrying capacity of the ship would have to be considerably reduced to make room' for the stout bases that would be necessary right down to the bottom of the holds. Even so the business of staying them up would be very difficult, although the wide flange at the top of the tower, which prevents the vortex motion of the air being wasted, would serve its purpose in this. Funnels are much smalle", but it sometimes happens that one is rol'.ed overboard in a beam sea, while even stayed pole masts are lost in the same way. Therefore it would appear that, unless it is found possible in ocean-going ships to use towers which are proportionately of infinitely smaller size, the system will only be really serviceable for small and fine-weather craft. At the same time it is certainly a big step in the direction of improving the efficiency of wind-power, and of using some of the many wasteful principles of aerial navigation for the economical carriage of merchandise.