types in some six to eight months, as U.B.and U.C.

boats began to be delivered as early as April, 1915, and it is certain that they were not ordered before August, 1914.
The time taken by the Germans to build submarines of the U type was estimated by us at twelve months, and that of submarine cruisers at eighteen months.

German submarine officers gave the time as eight to ten months for a U-boat and eighteen months for a submarine cruiser.
(It is to be observed that Captain Persius in a recent article gives a much longer period for the construction of the German submarines.

It is not stated whether he had access to official figures, and his statement is not in agreement with the figures given by German submarine officers.) It is of interest to note here the rate of ship production attained by some firms in the United States of America during the war.
As I mention later (_Vide_ Chapter vi, p.

157), the Bethlehem Steel Company, under Mr.Schwab's guidance, produced ten submarines for us in five months from the date of the order.