102 . NON-ROLLING PASSENGER LINERS. 



tion with the natural period of the ship and also with the period of the sea. So at 

 last this phase of the art has had the extremely great advantage of passing under 

 critical review by probably the greatest living authority on these matters. 



The difficulty with all of these attempts on this most important problem can be 

 reduced to an extremely simple proposition : — With all of these methods of attack, 

 a pound weighs only a pound and its effectiveness is measurable in simple terms of 

 the lever-arm of its application, or the distance from the center of oscillation of 

 the ship at which the moments become effective. This is the reason for the exces- 

 sive and even prohibitive weights necessarily present in all these methods of reduc- 

 ing the roll of ships. 



Now what is wanted is not the reduction of roll, but the actual prevention of 

 all rolling of ships, and it is just here that the powers and resources of the active 

 gyroscope step in. For years engineers have observed the strange peregrinations of 

 the gyroscope, but have failed to perceive the enormous powers that lie dormant in 

 this simple apparatus, only awaiting the application of artificial "precession" to place 

 it under perfect control and to render it abundantly serviceable for stabilizing even 

 the largest ship. By the way, the larger the ship is, the easier it is to stabilize her. 



In the gyro we have a most unusual illustration of the phenomena that Cicero 

 classed among "real blessings" ; that is, when nature's laws work to aid rather than to 

 obstruct progress, by no means a too frequent occurrence in engineering. The 

 gyro outclasses all other mechanisms in that, while its weight and cost vary as the 

 cube of a lineal dimension, its stabilizing power varies no less than the fifth power. 

 This runs into a very great gain in gyro stabilizers for large ships. 



Why is the gyroscope more available for solving this great problem than the 

 tanks on the one hand or the great pendulum of Thornycrof t on the other ? The 

 answer is simple. Whereas in the prior art, as we have stated, a pound is only a 

 pound, in the gyroscope a new and extremely far-reaching situation is created. In 

 arriving at the powers available to stabilize the ship with the gyro, every pound is 

 multiplied by the velocity of the particle, so that a comparatively few pounds are 

 actually capable of doing the work of tons. With the active gyro this is all held 

 in phase, and, as described, is available for the important purpose of holding the 

 ship free from even the beginnings of roll. 



Those unfamiliar with the subject, and even some naval architects, have feared 

 that the forces and stresses involved might endanger the ship's structure in case of 

 a heavy storm. The exact nature and magnitude of these stresses are perfectly well 

 understood and have now been brought under careful observation in quite a large 

 number of equipments in actual service. We are therefore speaking from a wide 

 range of accurate knowledge on this important item, and it will be interesting to 

 know that the conclusions by the highest authorities are that a ship which freely 

 rides the waves with its mast held vertical, being completely stabilized by the little 

 gyro equipment in her hold, is subjected to less than one-fourth and often less than 

 one-sixth of the very large strains present when it is allowed to roll under exactly 

 the same storm and weather conditions and with the heading unchanged in the same 



