LAUNCHING OF SHIPS IN RESTRICTED WATERS. 211 



Total energy absorbed by water resistance 66,740,000 ft.-lbs. 



Total energy absorbed by brake resistance 138,360,000 ft.-lbs. 



Total energy as recorded from curves 205,100,000 ft.-lbs. 



Kinetic energy of vessel traveling at 19.4 feet per second, when 



brakes are applied 201,600,000 ft.-lbs. 



Difference 3,500,000 ft.-lbs. 



Representing an error or discrepancy of less than 2 per cent. 



Note that in this case the resistance of the water absorbed about 32^ per cent 

 of the total energy. 



Inasmuch as the results shown in the preceding paragraph are obtained by en- 

 tirely independent methods, the check is very positive and the agreement remarkably 

 close. The curve of brake pull is considered so reliable, that, from data on similar 

 model runs to be made just before the launch, the pressure in the hydraulic brake 

 cylinders and the point of application of the brakes will be determined. 



For purposes of comparison, the velocity-distance curve of the Cuyama has 

 been added. The similarity between this curve and the one obtained from the model 

 is most apparent. 



It has been necessary, throughout this paper, to comment rather briefly upon 

 what is really a very comprehensive subject, and it has been the intention to sup- 

 plement this brief description with such photographs and plans as would serve to 

 explain clearly the subject-matter of this article. Unfortunately, at the time this 

 paper was prepared, the launch of the battleship California had not taken place, and 

 it was not possible to make extended comparison of the data obtained from the 

 model and the final data from the actual launch. It is hoped that, when this matter 

 has been worked up, there will be further opportunity to present it to the Society 

 in a subsequent paper. 



DISCUSSION. 



The President : — The paper by Captain Gleason and Lieutenant Commander Saunders, 

 entitled "The Launching of Large Vessels in Restricted Waters," is now open for discussion. 

 Professor Hovgaard, may we hear from you on this subject? 



ProEEssor William Hovgaard, Member: — I think any one who has had to do with 

 the launching of ships in restricted waters will recognize the immense value of this paper, 

 where, I believe, for the first time we get connected and scientific data of a launching 

 under these particular conditions. 



I have myself felt the need of information of that kind on two occasions. The first 

 was in 1895, when we launched the Imperial Russian yacht, the Stan,dard, built for the Czar. 



