50 RECENT PROGRESS WITH THE ACTIVE TYPE OF GYRO-STABILIZER. 



pected direction and characteristic of the keen insight of our officers. This verdict was that 

 the navy did not possess personnel who could be depended upon to adjust the periodicity of the 

 stabilizing tanks so as to bring about the described critical relation between the three elements ; 

 without this critical relation being reached and maintained, the tanks were not only worthless 

 but more likely to be a menace than a benefit. 



Among other disadvantages of tanks was the fact that the construction, together with 

 the water in the tanks, had to run up as high as 5 per cent of the total displacement of 

 the ship to be at all effective. The specific gravity of water being only 1, the tanks have to 

 be very large. Furthermore, they were compelled to occupy the most valuable amidship sec- 

 tion of the ship at its fullest beam, otherwise their lever arms were inadequate and they 

 had to be made still larger, heavier and more unwieldy. 



After years of investigation this system of stabilization has been condemned and its use 

 discontinued. At best, all of these systems, regardless of their origin or character, are pas- 

 sive and seek only to diminish to a certain extent the rolling of ships. 



In contradistinction to this class, the new stabilizer is offensive in its method, 

 it approaches the proposition from an entirely new standpoint, namely, the suppression of 

 all roll, never allowing the ship to start or begin to roll, as has been previously explained 

 by me before this body. 



The President : — I am sure we are all very much interested in Mr. Sperry's paper and 

 have been much instructed by it, and the thanks of the Society are tendered to Mr. Sperry 

 for the paper. 



The next paper to be considered is No. 5, entitled, "The Determination of the Resist- 

 ance of Ships. Present Day Status of the Art," by Mr. Ernest H. Rigg, Member. 



In presenting the paper, Mr. Rigg said : — "We are singularly fortunate in being favored 

 practically every year, both here and abroad, with the results of work done in the various ex- 

 perimental basins. The gentlemen in charge of the tanks in this country are very free in com- 

 municating the results of their work to the Society. I therefore found considerable difficulty 

 in bringing anything new to your notice, and nothing new is claimed for this paper, but I 

 thought it would be of interest and value to those who are engaged in powering ships to be 

 presented with a general statement as to the present status of the art. 



"My paper has, therefore, been an attempt to summarize and bring before you in concise 

 form as much of the modern literature on this subject as I could find. I do not propose to 

 read the paper, as the discussion on this and the other papers will be of more value than 

 reading through the whole paper. 



"Referring to Mr. Bernhard's paper of this morning and the problems of propelling that 

 type of vessel. Professor Sadler told us of some work done by the government, which is at 

 present not made public. I think there is something that will be of interest to all concerned 

 in that type of vessel in Mr. Baker's book which has been recently published ; it has an in- 

 teresting section on the propulsion of barges and barge forms, which probably covers a good 

 deal of the matter that is in the government publication which Professor Sadler spoke of." 



Mr. Rigg then proceeded to abstract his paper briefly. 



