ACTIVE TYPE OF STABILIZING GYRO. 209 



The active equipment, as we have seen, is different. It most promptly deals 

 with each momentary energization and "has no memory ;" it cares not when 

 nor from what direction the previous stress attacked the ship. 



The surprisingly small magnitude of the whole gyro equipment is due 

 largely to its unique method of operation; that is, it makes up in activity 

 and promptness what it may seem to lack in size and weight. 



Herr Frahm mentions the tanks of the Ypiranga as changing the center 

 of gravity of this vessel to the extent of some 2,700 foot- tons and states that 

 gyros with this torque value had not been developed at that date. Gyro- 

 scopes can now be developed with low specific stresses of much greater 

 torque value than this figure indicates, with the further gain that the center 

 of gravity of the ship is not disturbed, nor would it undergo any change 

 whatever. Moreover, with active gyros, torque of this magnitude is not 

 required in ships of this tonnage and slow period for their effective stabiliza- 

 tion. In connection with this statement regarding tanks, Herr Frahm 

 failed to point out how many oscillations of the ship were required before 

 reactions of this magnitude had been set up, or if developed by one or two 

 large oscillations how great an amplitude was required in such oscillations 

 of the ship. We now know what these are, and no ship could be considered 

 stabilized while obsessed with this motion. One great difficulty with the 

 tank proposition is that its phenomena are pendulous and resonant from 

 start to finish, and must be in fact co-pendulous with the ship and therefore 

 far too slow to deal with individual wave impulses. As a matter of fact, 

 the first impulse or impulses are never dealt with, but instead the boat rolls 

 in response to the increments in the act of creating the reaction within the 

 tanks. Thus we see that as a matter of fact individual increments are 

 never dealt with until an accumulation of a number of such impulses has 

 resulted in actually rolling the ship, whereas the active gyro deals with each 

 individual increment and no accumulation is possible. 



Under the conditions shown by Figs. 4 to 7, we would have a steady ship 

 in place of the oscillations recorded when all the tanks were in full operation 

 and the plant itself is found to occupy between one-tenth and one-twentieth 

 the space, the proportion being 1.5 to 21.7; the gyro plant weighing only 

 10 to 20 per cent of the tanks and contents. Again, this small space is 

 practically independent of location. It need not occupy the most valuable 

 amidship space nor extend entirely across the ship at point of greatest beam. 

 It may even be divided up in two smaller spaces and stowed away at any 

 point selected by the designer. In this way the small space required may 

 be that which is least valuable in the whole ship. Again, the gyroscopic 

 plant, unlike the tanks, is entirely independent of the height component of 



