Burney), and was on similar lines to his valuable invention for
the protection of warships. The latter system had been introduced into
the Grand Fleet in 1916, although for a long period considerable
opposition existed against its general adoption, partly on account of
the difficulties experienced in its early days of development, and
partly owing to the extensive outlay involved in fitting all ships.
However, this opposition was eventually overcome, and before the end of
the war the system had very amply justified itself by saving a large
number of warships from destruction by mines. It was computed that there
were at least fifty cases during the war in which paravanes fitted to
warships had cut the moorings of mines, thus possibly saving the ships.
It must also be borne in mind that the cutting of the moorings of a mine
and the bringing of it to the surface may disclose the presence of an
hitherto unknown minefield, and thus save other ships.

Similarly, the "Otter" defence in its early stages was not introduced
without opposition, but again all difficulties were overcome, and the
rate of progress in its use is shown in the following statement giving
the number of British merchant ships fitted with it at different periods
of 1917:

By July 1, 95 ships had been fitted.
By September 1, 294 ships had been fitted.
By December 1, 900 ships had been fitted.

The system was also extended to foreign merchant ships, and supplies of
"Otters" were sent abroad for this purpose.

A considerable number of merchant ships were known to have been saved
from destruction by mine by the use of this system.

DEFENSIVE ARMING OF MERCHANT SHIPS

The _defensive arming_ of merchant ships was a matter which was pressed
forward with great energy and rapidity during the year 1917. The matter
was taken up with the Cabinet immediately on the formation of the Board
of Admiralty presided over by Sir Edward Carson, and arrangements made
for obtaining a considerable number of guns from the War Office, from
Japan, and from France, besides surrendering some guns from the
secondary and anti-torpedo boat armament of our own men-of-war,
principally those of the older type, pending the manufacture of large
numbers of guns for the purpose. Orders for some 4,200 guns were placed
by Captain Dreyer, the Director of Naval Ordnance, with our own gun
makers in March, April and May, 1917, in addition to nearly 3,000 guns
already on order for this purpose;