TO THE NEEDS OF THE UNITED STATES NAVY. 121 
simply enrich your flame as desired and keep up combustion in an enclosed chamber, pumping 
out the excess. These are just casual suggestions, but I have looked into the conditions and be- 
lieve that such things are practicable. 
The only way that the navy will ever get anything of that sort is by building the sub- 
marines itself, or putting the very highest grade of engineers on the job and spending the 
money to do it. The submarine problem isa highly specialized demand. It is not a thing 
which any commercial concern is interested in developing. There are certain submarine 
builders in this country that get a large amount of business, and have been able and enter- 
prising in developing this art, but the tendency of manufacturing companies engaged in the 
production of such things is to do the things which are easiest for them, and which they 
know how to do. They develop a certain kind of thing and want to manufacture that thing. 
If you depend simply upon somebody outside to give you a submarine, you are apt to get 
the same thing over and over again, because that is the cheapest and best thing from the 
builder’s standpoint. 
Rear ApmiraL A. W. Grant (Communicated) :—There are two statements made in 
the paper of Capt. W. L. Rodgers which, if accepted, will set us back in obtaining an of- 
fensive submarine type for some years to come. They are:— 
1. “High submerged speed and great submerged radius are comparatively secondary 
affairs unless most radical improvements are brought about in the methods of submerged 
propulsion, so that high submerged mobility may be obtained without undue sacrifice of sur- 
face mobility.” 
2. “The size and type of coast-defense submarines of about 500 tons now favored by our 
Navy Department seems the proper and logical one for American use.”’ 
From the most authentic accounts of German war submarines of the type of the U-53, 
we learn that Germany has actually developed a very formidable offensive type of vessel. 
This submarine has reliable Deisel engines that give a surface speed of about 16% 
knots on a shaft horse-power of about 1,400. It carries fuel sufficient to cross the Atlantic, 
operate on this side several days, and return without refuelling or repairing. How many 
surface vessels of war are as capable? 
In all late German designs the battery weight and space is a fixed proportion of the 
total displacement. The U-53 can remain submerged for several days at low speeds. From 
fairly reliable authority it is learned that the large German war submarines can run sub- 
merged at a speed of 8 knots for eight hours and can run at about 2 knots for from 
seventy to eighty hours. 
Submerged radius of action when expressed in time rather than in miles conveys more 
to one’s mind. Submersibility is the submarine’s means of attacking an enemy or remaining 
concealed from vessels it does not desire to attack. A submarine will never travel sub- 
merged when the surface is available. It travels submerged, when not attacking, merely to 
conceal its whereabouts. If we know that a submarine can remain in concealment for nearly 
100 hours and during this time can without suffering detection obtain continuous sight of 
its surface surroundings (except of course at night or in a fog), then we at once appreciate 
that this is a quality of very great offensive advantage. 
Having such a battery as is installed in the submarines under discussion and in the 
Deutschland, by providing suitably large motors a very high speed can be obtained for a 
