pter 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. Mr. Schwab himself informed me
that towards the end of the war he was turning out large destroyers in
six weeks. The Ford Company, as is well known, produced submarine
chasers of the "Eagle" type in even a shorter period, but these vessels
were of special design and construction.

I have dealt so far with the question of anti-submarine measures
involving only the use of destroyers and other small surface craft.
There were, of course, other methods both in use and under consideration
early in 1917 when we took stock of the situation.

For some time we had been using _Decoy vessels_, and with some success;
it was possible to increase the number of these ships at the cost of
taking merchant ships off the trade routes or by building. A very
considerable increase was arranged.

The use of our own _submarines_ offensively against enemy submarines had
also been tried, and had met with occasional success, but our numbers
were very limited (the total in December, 1916, fit for oversea or
anti-submarine work was about forty). They were much needed for
reconnaissance and offensive work against surface men-of-war in enemy
waters, and only a few were at the time available for anti-submarine
operations, and then only at the cost of other important services.

The _hydrophone_ had been in the experimental stage and under trial for
a considerable period, but it had not so far developed into an effective
instrument for locating submarines, and although trials of the different
patterns which had been devised were pushed forward with energy, many
months elapsed before it became a practicable proposition.

One of the best offensive measures against the enemy submarines, it was
realized, was the _mine_, if laid in sufficiently large numbers.
Unfortunately, in January, 1917, we did not possess a mine that was
satisfactory against submarines.

Our deficiency in this respect was clearly shown in the course of some
trials which I ordered, when one of our own submarines was run against a
number of our mines, with the result that only about 33 per cent. of the
mines (fitted, of course, only with small charges) exploded. The Germans
were well aware that our mines were not very effective against
submarines.

We possessed at the time mines of two patterns, and whilst proving
unsatisfactory again