WHAT THE U-BOATS ARE DOING.

Hokitika Guardian, 27 October 1917, Page 4

WHAT THE U-BOATS ARE DOING.

SOME UNKNOWN FACTORS.

(From a Naval Correspondent.)

In the twenty-two weeks covered by the new series of submarine returns the Germans have sunk 597 British merchantmen, of which only 162 were of less than 1,600 tons, and 143 fishing craft.

In addition to these, .10 British ships, totalling 48,000 tons, were announced on March 23 as having been sunk by the Mowe, while a week later came the report of six of our ships having been destroyed by the Seadler. The Mowe got safely back to Germany. What happened to the Seadler we do not know.

Nor do we knowhow many of our ships have been damaged and beached or otherwise prevented from sinking ; nor how much is lost in time and tonnage while such ships are being salved and repaired ; nor how many ships belonging to our Allies and to neutrals have been sunk; nor—most important of all—what is our loss expressed in the only intelligible term of tonnage.

For reasons best known to themselves the American newspapers are practical!)’ unanimous in taking an average of 4,500 tons for the ships oi 1,600 tons and above. If we further assume an average of i.coo tons for vessels. under that figure leaving fishing craft out of the reckoning), it will be found that on these bases pur loss in the 22 weeks ending last/ Sunday amounts to 2,119,500 tons, which approximates very closely to the statement of the naval correspondent of “ The Times ” on Thursday that “ something like 2,000,000 of British gross tonnage has been destroyed ” in the last six months. The higher figure represents 96,340 tons a' week, and as nearly as possible a round 5,000,000 a year. What is there to be learned from the unsatisfying official figures ? Summarising the 20 weeks from March 4th into four periods of five weeks each, the first thing noticeable is the striking falling-off in the number of ships attacked, the numbers for the successive periods (excluding fishing craft) being 196, 314, 236, and 177. In other words, a weekly average of 63 in the second period fell to 35.4 in the fourth. The decline may be clue to a thinningout of the U-boats—let us hope it is, tor sinking them is the only real solution of the problem. On the other hand, purely defensive measures may account for a good deal, such as the better protection of ships by patrol craft (sea and air) in the | danger zones and the surer precautions taken by shipmasters. I There is no reason to believe that the Germans fight shy of armed ships, for more than 80 per cent of those above i,600 tons recently sunk were so defended. MORE BIG SHIPS SUNK. There is no definite movement observable in the percentage ofj ships escaping. 111 the first period i this was 39-3, in the second 36-9, in j the third 44-9, and in the fourth (June 17 to July 22) 407. The comparative steadiness of the figure is probably due to the fact that as the arming of our ships proceeds ; the U-boats trust less to the gun and more to the torpedo, so that what we gain by adopting a means of defence against .surface craft, or submarines acting as such, we lose by driving the enemy back upon bis main reserve, which is his invisibility. Possibly the same factors weigh for something in reducing the number of attacks, tor a submarine operating mainly under water will naturally find fewer opportunities for effective work ■ than if, relying upon her guns, she ! could openly cruise around for victims at 18 or | In a general way everyone realises that the enemv is endeavourino- to concentrate his energies on heavy 1 ships, but the official figures by which his changing outlook on this : ooint may be traced are very sig- j lificant. In the first period (five weeks) he sank 35 ships ' under : r,600 tons and 84 above; i n the • second, 63 and 135 respectively; in i :he third, 29 ,and ; 101; and in the 1

fourth, 2i and 84. Expressed in another way, lie sank, for each 2 small ships, 5 big ones in the first period, 4 in the sfecond, 7 in the third, and 8 in the fourth. The change may possibly be due to pure chance ; but it is also probable that, driven under water by defensive armaments and .compelled to rely upon the costly and somewhat erratic torpedo, the U-boats-prefer to risk these weapons against something that at once offers a bigger target and holds the promise of a more imposing entry on the roll of piratical achievement.