One curious instance occurred on March 28, 1918, of a merchant ship being saved by a 7.5-inch howitzer.  A torpedo was seen approaching at a distance of some 600 yards, and it appeared certain to hit the ship.  A projectile fired from the howitzer exploded under water close to the torpedo, deflected it from its course, and caused it to come to the surface some 60 yards from the ship; a second projectile caused it to stop, and apparently damaged the torpedo, which when picked up by an escorting vessel was found to be minus its head.

Delivery of howitzers commenced in June, 1917, and continued as follows: 

Total completed,
No. of Howitzers      including those
Date.               actually issued.      under proof.

July 24, 1917              35                   48
October 1, 1917            92                  167
December 10, 1917         377                  422

The slow rate of delivery, in spite of constant pressure, which is shown by these figures gives some idea of the time required to bring new devices into existence.

PROJECTILE FOR USE AGAINST SUBMARINES

In January, 1917, the Director of Naval Ordnance was requested by the Anti-Submarine Division of the Naval Staff to carry out trials against a target representing the hull of a German submarine, so far as the details were known to us, to ascertain the most suitable type of projectile amongst those then in existence for the attack of submarines by guns of 4.7-inch calibre and below.

The results were published to the Fleet in March, 1917.  They afforded some useful knowledge and demonstrated the ineffectiveness of some of the shells and fuses commonly in use against submarines from 12-pounder guns, the weapon with which so many of our patrol craft were armed.  The target at which the shell was fired did not, however, fully represent a German submarine under the conditions of service.  The trials were therefore continued, and as a result, in June, 1917, a further order was issued to the Fleet, giving directions as to the type of projectile to be used against submarines from all natures of guns, pending the introduction of delay action fuses for the smaller guns; this was the temporary solution of the difficulty until a new type of shell evolved from the experience gained at the trials could be produced and issued.  The trials, which were exhaustive, were pressed forward vigorously and continuously throughout the year 1917, and meanwhile more accurate information as to the exact form of the hull and the thickness of the plating of German submarines became available.  Early in 1918 the first supplies of the new fuses were ready for issue.

SMOKE APPARATUS

The earlier smoke apparatus for supply to merchant ships was designed towards the end of 1916.

One description of smoke apparatus consisted of an arrangement for burning phosphorus at the stern of a ship; in other cases firework composition and other chemicals were used.  A dense smoke cloud was thus formed, and, with the wind in a suitable direction, a vessel could hide her movements from an enemy submarine or other vessel, and thus screen herself from accurate shell fire.