104 RESULTS OF MODEL TANK EXPERIMENTS TO 



any part of her hull and the brake had to be fitted on by means of a molded frame. 

 There were no accurate means of determining the total instantaneous indicated 

 horse-power nor the exact speed. 



When the subject was revised, the model tank was considered by far the most 

 accurate method of determining the data to be used in designating a brake. To 

 satisfy the ideas of many concerned, various forms of the brake were considered, 

 principally with the idea of controlling the brake by power so as to open and close 

 at will, the vessel going at full speed. 



Scheme i. — Long hydraulic cylinders installed athwartship on a stiffened bulk- 

 head to work connecting rods attached to the brakes. This involved an additional 

 weight of about 190 tons, including 33 tons of contained water. 



Scheme 2. — In order to reduce weights, especially that of contained water, a 

 toggle joint arrangement was studied to reduce the power required and to reduce 

 the peak load when the brakes were to be started in. This involved a stress of 

 340,000 pounds on each of three principal connecting rods and 320,000 pounds on 

 each of three lesser members. 



Scheme 5. — Rack and pinion arrangement, allowing very little contained water. 

 The diameter of the vertical shaft working the pinions and the width of the gear 

 needed rendered this scheme out of consideration. 



Scheme 4. — Same as Scheme 3, but with the idea of pushing the brake out to 35° 

 to assist the rudder. This required too much machinery to develop the power neces- 

 sary, about 500 estimated horse-power for a pair of brakes 9 by 13 feet. 



Many other schemes were studied out, but the weights and power required 

 made any and all of them impracticable. 



The final conclusion reached — that the simplest form of brake designed to be 

 set in the side of a vessel, to be released instantly by the officer on the bridge by 

 throwing a lever and open by the pressure of the water without further thought; 

 to be supplied with only enough power and mechanism to haul in the brake when 

 the vessel was stopped or going astern and lock it fast for future use — was the only 

 practical solution of the question. 



With these points in view, a type design was made for the Canadian Pacific 

 S. S. Empress of Asia, practical, strong and simple, for emergency use only. The 

 officer on the bridge has but to pull a lever and the brake will open and exert its re- 

 sistance. When the danger is past, it requires but the attention of one man on each 

 side to haul in and secure the brake. 



With this done, the technicist closes his work and the financier and promoter 

 begins to write his story. 



