ON THE STEERING QUALITIES OF SHIPS. 73 



kuown that the waves set up by the model bear the same relation to the 

 size of the model as the ■waves set up by the ship do to the ship when, and 

 only when, the speed of the model is to the speed of the ship in the ratio of 

 the square root of the ratio of their lengths. 



Since this fact has been recognized, most important information has been 

 obtained by experimenting on models. Mr. Froude, by recognizing this law, 

 has been able to bring the comparison of ships by means of their models to 

 such a degree of perfection, that he can now predict with certainty the com- 

 parative and actual resistance of ships before they are constructed, and the 

 great practical value of his results have been recognized by the Admiralty. 



What I propose is virtually to extend these experiments on models so as 

 to make them embrace the steering-powers of ships as well as their resis- 

 tances. The manner of experimenting would have to be somewhat altered. 

 Steam-launches would have to be substituted for dummy models ; but the 

 principle of the experiments would have to remain the same, and the speed 

 of the launches must be regulated by the same law as that of the models. 



The turning qualities of such launches might be verified by comparing 

 them with the turning qualities of the ships as found by actual experiment ; 

 and then the models might be handed over to the officers of the ships, and 

 they might practice encounters and manoeuvres until they knew not only 

 what they could do with their ships, but what it was best to do in order to 

 outmanoeuvre each other, and this without any cost or risk. 



The behaviour of the models would be in all respects similar to that of the 

 ships, the only difference being that the manoeuvres would be on a smaller 

 scale ; and the scale of the manoeuvres would be the same as that of the 

 models, so that the step from the models to the large ships would be easy ; 

 and familiarity with the working of the ships as well as the models under 

 ordinary circumstances would prepare the officers for using the ships in an 

 actual fight as they have been accustomed to use the models in their friendly 

 encounters. The scheme here proposed has its parallel in military schools. 

 Although " autumn manoeuvres " and sham fights afford soldiers a much 

 better opportunity of preparing themselves for battle than any thing at 

 present within reach of the sailors, still the war game appears to be 

 growing in favour, and this is nothing more than practising manoeuvres in 

 miniature. 



Independently of their value as a means of training naval officers, such 

 models would afford a means of studying naval tactics. From them might be 

 learnt the way in which a ship should strive to approach another of nearly 

 equal power and speed, so as to use her ram to the greatest advantage ; and 

 of this as yet but very little can be known ; and, except on models, it can 

 only be learnt from experiments oji the ships. 



Important as are the laws which have been verified by the Committee on 

 the steering of screw-steamers, it appears to me that the most important 

 lesson to be learnt from their investigation is, that there is nothing capri- 

 cious in the behaviour of these ships. To realize the value of this lesson 

 the investigation must be followed up ; and it appears that the best way to 

 do this would be by the aid of model launches on the plan thus roughly 

 sketched out. 



