TO THE NEEDS OF THE UNITED STATES NAVY. 129 
stability. But if you take the same vessel built of the same total weight of material and 
change it to this form (indicating) and reduce the thickness of material in the smaller 
diameters so that the hull is uniform in strength and capable of withstanding the same sub- 
merged pressure, the center of gravity and center of buoyancy of the vessel would both rise 
but the center of buoyancy would rise the more rapidly and would be about here (indicat- 
ing). So we have a vessel of the same weight of construction and capable of resisting the 
same pressure of water when submerged, because it is composed of the same circular dimen- 
sions, but we would find it had a considerable amount of stability due to the fact that the 
center of gravity and buoyancy, instead of being in the center of this spindle, both at the 
same point, would be at some other point considerably higher. It has worked out in the 
actual design of a submarine of the same length and diameter, so that it made a difference 
of 6 inches; in other words, we got an increased stability of nearly 50 per cent simply due 
to the change of the form. We believe this form is also better than the cigar-shaped form 
for surface speed as it tends to reduce the bow wave. 
Now Captain Niblack referred to the German type of boat, which resembles more our 
old Argonaut or some of our Russian designs than it does our present-day boats. The orig- 
inal design which I submitted to the Navy Department in 1893 was a double-hull boat—that 
is, with an inner and outer hull, the space in between being divided for the main-water bal- 
last tanks, with the machinery placed low down in the hull, for the purpose of getting 
greater stability, and I am not sure but what that is a better design than some of the later 
ones, although I do not know of any boat ever built that way. 
The object of having the double skin is, in case of puncture of the outer hull to pre- 
vent the foundering of the vessel. In some of our later designs of boat we accomplish 
almost the same thing, having our superstructure extend down over the inner ballast tanks, 
but there has been a great difference of opinion among naval architects as to the proper 
width of the superstructure. 
The Germans have kept to the general form of the old Argonaut in having a super- 
structure wider and longer than the inner pressure-resisting hull, while other designers have 
reduced its width with the object of getting increased submerged speed. 
The submarine Protector was shipped to Russia in a special ship. Other Lake type 
submarines were shipped by the Hamburg-American line vessels. They were unloaded and 
re-shipped at Hamburg, so that the Germans had ample opportunity to inspect these boats. 
One of the large German shipbuilding companies took a contract from the Russian Govern- 
ment to build three boats on a modified Lake design, as they understood it from published 
descriptions and otherwise, but they made one mistake in that design—they attempted to 
get too great a speed and made the lines of the boat a little too fine and carried heavy flat 
fuel tanks in the superstructure, which had to be filled either with fuel or water to prevent 
collapse when submerged. This increased the top weights to such an extent that the boat 
lacked stability. I was informed she submerged at an angle of about 45 degrees in Kiel 
Harbor and stuck in the bottom so firmly that they had to get tugboats to pull her up. 
In the meantime we delivered the Protector and five other boats to the Russian Govern- 
ment, all functioning satisfactorily. 
After the German boat had been partly rebuilt three times I was asked to go to Germany 
for a consultation with the managers of Krupps to see if I could advise them how to correct 
their trouble. After a consultation with Admiral Barandon, who was the head of the Krupp 
