126 TRANSACTIONS OF THE ROYAL CANADIAN INSTITUTE  [VOL. XI. 
probably to gain greater tank volume, greater stiffness in the surface 
condition, and greater safety against collision. The displacement in 
the E-class is #$ts. and in the six boats of the F-class laid down in 1913 
it reaches i¥ysts.and the speed is tikts. No data are known about later 
boats, but they are probably larger and more powerful. 
In the United States the Electric Boat Company developed the 
Holland type. Boats of the M-class have a submerged displacement 
of 800 ts. A larger boat of about 1200 ts. displacement is to be laid 
down this year. “The price of this boat is 14 million dollars. The 
speed according to press reports is to be itkts. The reserve buoyancy 
of the American Holland boats has been gradually increased and the 
form of the superstructure is now ship-shaped in the bow. 
The Holland type has been adopted also by the Whitehead firm in 
Fiume. The bow of the Whitehead boats is similar to that of an 
ordinary torpedo boat. 
The Lake boats have likewise developed to larger size. The Seal 
carries torpedo-tubes in the superstructure. 
In France a greater differentiation took place than in other navies. 
The two main types, the submarine and the submersible, co-existed and 
were developed simultaneously to greater sizes, but gradually approached 
each other. After the comparative trials in 1908 between submarines 
of the Emeraude class and submersibles of the Pluviose class it appears 
that the submarine was altogether abandoned. In five boats laid down 
last year the displacement is ists. 
In Italy submersibles of the Laurenti type have been developed. 
They have the same principal features as the Laubeuf boats of which 
they may be considered a variety, but differ from them in some respects. 
The strength hull is not always circular, although in later boats this 
seems to be the case. Some have horizontal propellers for submerging. 
Some recent boats have three propellers for propulsion. 
In Germany the Germania firm in Kiel constructs submersibles of 
the d’Equevilley-Germania type, likewise derived from the Laubeuf 
boat. The strength hull is cylindrical and is built up of several welded 
sections without frames. The sections are scarfed together, except 
one of the sections amidships which is connected to the others by bolted 
flanges so as to facilitate shipping and unshipping of the machinery. 
The ballast and fuel tanks are outside the strength hull amidships and 
at the ends. Only one internal tank, used for compensating for incidental 
variations in buoyancy, is fitted amidships. The boats dive almost on 
an even keel. The latest German boats are probably of about the 
same size as the English F-class. 
