Consequently we were dependent for the largely increased work on improvised craft, and the very greatest credit is due to all who were concerned in this arduous and dangerous duty that the waters were kept comparatively clear of mines, and that our losses from this cause were so small when the immense number of mines swept up is considered.
Fortunately the enemy lost very heavily in submarines of the U.C., or minelaying type, largely because they were working of necessity in waters near our coast, so that our anti-submarine measures had a better chance, since they were easier to locate and destroy than submarines working farther afield.

By the commencement of 1918 the average number of mines swept up monthly showed a very remarkable decrease, the average for the first two months of that year being only 159 per month, eloquent testimony to the efficiency of the anti-submarine measures in operation during 1917.

I have no information as to the figures for the remaining months of 1918.
The record of minesweeping work would not be complete without figures showing the damage caused by mines to minesweeping vessels.
During the last six months of 1916 the average number of these craft sunk or damaged by mines _per month_ was 5.7, while for the first six months of 1917 the figures rose to ten per month.

For the second six months of 1917 the figures fell to four per month, a reduction even on the losses towards the end of 1916, in spite of the fact that more mines were being dealt with.

This reduction may have been due to improvements effected in organization as the result of experience.
Similarly the total number of merchant ships sunk or damaged by mines, which during the first six months of 1917 totalled 90, dropped in the second six months to 49.
By far the greater proportion of mines swept up were laid in Area 10--i.e.the Nore, Harwich and Lowestoft area.