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Mechanically Produced Rolling Enables a Vessel to Break a Y ] y 2 Channel More Easily—Description of Haagenson Method cd are with few exceptions moderately sized, powerfully engined vessels, of the screw type. They are very strongly built with the lines at the water plane a continuous curve, and the bows bulbous or spoon shaped. Some governments, notably the Rus- sian, have large, powerful ice breakers. One of the Russian is Ermack, which develops 10,000 horsepower. She was ‘built with four screws, three of which were aft and one forward. The for- ward screw has since been removed. This vessel was built by Armstrong, Whitworth & Co. on the Tyne river, Le crushers, or ice breaking vessels, CROSS SECTION OF VESSEL’S HULL WITH GYROSCOPES INSTALLED England, about 15 years ago, and is the largest and most powerful ice breaker in the world. The Canadian govern- ment has also powerful ice breakers. Such vessels as these, on account of their design, the extremely heavy en- gines and boilers and the large space occupied by the bunker fuel, can carry no cargo. As a result, they are lim- ited in’ their use to the breaking of a path for other vessels, thus making their use expensive. On the Great Lakes are to be found ice breakers of the cargo carrying type, such as the numerous car ferries. These are large vessels, displacing loaded about 6,000 tons. They vary from 300 to 400 feet in length, between 50 and 60 feet beam and draw loaded about 15 feet of water. These vessels have about 3,000 horsepower in propelling machin- ery on two screws, both of which are aft, except in the case of the ferries at Mackinaw, which have one screw forward and one aft. Ice breakers of the cargo carrying type frequently experience great diffi- culty through getting wedged in the ice. Cases are on record where they have been held out in the lake all winter. This difficulty arises from the fact that, since these vessels are to be used com- mercially, the ideal lines on which the ‘worms is pure ice breaker is designed cannot be employed. Neither can the ferries be engined so heavily as an ice breaker. It has long been believed by many vessel men that if an _ oscillating or rolling motion could be imparted to these vessels, their efficiency as ice breakers would be greatly increased, but the means of effecting this was not available until recently. In 1914, Capt. B. T. Haagenson, Ashtabula, O., at that time commander of the car ferry AsH- TABULA, invented a method of applying the oscillating principle to ice breakers. To effect the rolling moments he em- ployed a large gyroscope, which by spinning at the rate of from 600 to 1,000 revolutions per minute and being precessed or turned by a steam engine, set up rolling moments enough to oscil- late or roll the vessel to any desired degree. An adaptation of the Haagenson in- vention is shown at the left. Two gyro- scopes are mounted in the hull, A, be- tween the decks, B and C. Each gyro- scope, D, is composed generally of a rotor, d, a shaft, d', and a motor, d’, all of which are contained within a cas- ing, d°. The casing is provided at its top and bottom with suitable posts or trunnions which are journaled in. sta- tionary journal blocks, b and c, secured to the decks, B and C, of the vessel. Such ball and roller bearings as are necessary to insure perfect ease of op- eration of the various parts of the gyroscope are employed. The lower part of the casing, d’, terminates in a worm gear, d’. Situated upon the deck, B, between the gyroscopes, D, is a reversible en- gine, E. The shaft, e, of this engine extends athwartship and has secured to each of its ends a worm, e’, which is adapted to mesh with the worm gear, d@’*. The angular inclination of both in the same direction and both worms are of the same pitch, causing a similar precessional move- ment to be set up simultaneously in both gyroscopes when the engine is operated. This precessional movement of the gyroscopes causes them to impart to the vessel a reverse thrust on the opposite sides of its keel which ‘results in an oscillating or rocking motion of the vessel. This may be accomplished by either running the engine continu- ally in one direction, or by reversing it and causing an alternate right and left hand partial rotation of the gyroscope 78 casings. Another adaptation provides for the use of only one gyroscope to accom- plish the same results. In order to realize the maximum influence of a single gyroscope, it is located as near the center of oscillation as possible and its spinning axis is swung at intervals corresponding to the natural periodicity of the vessel. With the gyroscope installed, Captain Haagenson believes that any ordinary ice breaker becomes vastly more ef- ficient. The wedging of these vessels is prevented and the continuous rolling motion eliminates also the skin friction CARFERRY MAITLAND NO. 1 She is Stuck in the Lake Ice, With the Crew Overboard Cutting Her Out. of the vessel’s sides against the ice. In addition, since the vessel is rolling as it advances, it will break the ice with one shoulder only at a time, this break- ing being done by the weight of the ship applied gravitatingly against the ice mass. To put it differently, the weight of the ship becomes a much greater factor in breaking the ice than in ordi- nary practice where merely the _ pro- pelling force is the sole reliance of ves- sels of this class. This invention, Cap- tain Haagenson points out, makes it possible to employ large cargo carrying vessels of any size for ice breaking service, provided the ships are of the full power class. In times like the present when sea- ports in high latitudes are so much in use it would appear that the invention is a timely one. Its employment would aid to eliminate the troubles experi- enced at Archangel, Russia, the only port in Europe available to the Rus- sians since the war began. This port is closed from November to May of each year, or for five months, resulting in greatly handicapping the military forces of the Russian Empire. Captain Haagenson points out the (Concluded on page 84)