Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Submarine Chaser Detachments One, Two, and Three
26th August 1918.
From: Force Commander
To: Commander Sub-Chaser Detachment, One Two and Three.
Subject: Summary of Sub-Chaser Operations.
1. The enclosed table, while not complete, is compiled from all the data available in reports from sub-chasers. The period of operations which it covers differs for the different bases, but reduced to a quantitative basis it would represent the operations of one hundred and thirteen chasers for one month, (including rest periods) from date of arrival from the United States.
2. Thirteen attacks have been made on what were thought to be submarines, and in six of the cases sound evidence has been verified by sight. In five cases the chasers have commenced the attack with the submarine within one hundred yards. In three of these close attacks sight verified sound. A total of ninety seven depth charges have been dropped in actual attack, exclusive of bombing, of oil spots etc.
3. Several of the attacks justified the belief that the submarine was at least damaged. In the Portland attack of May 30th, the submarine which was on the surface, was seen in the column of water from the depth charge explosion. At Corfu a joint Board of British and American naval officers appointed to report on the action of June 27th, reported that the submarine was “damaged and possibly, even probably destroyed.” The attack of June 28th also at Corfu was excellently conducted. All three boats were within hail of one another at the start of the bombing with the submarine plotted in and loudly heard sixty five yards ahead. Seventeen charges were dropped by the three chasers in a pattern surrounding this probable position. Darkness and a depth of 500 fathoms of water made the obtaining of any evidence almost an impossibility. The attack of July 10th at Plymouth was classed by the British Admiralty as “possibly slightly damaged”.
4. Possibly some of these other attacks are even more worthy of mention, but these serve to show that the chasers have made their pressure felt by the enemy submarines. From the standpoint of collecting evidence of damage it has been an important feature of the operations that many of the best attacks have been made at night, either in over 100 fathoms of
water or in a strong tideway. This is due of course to the fact that low visibility deprives the submarine of the protection he derives from seeing, while leaving him equally vulnerable to attack by sound.
Source Note: C, DNA, RG45, Entry 520, Box 387. Document identifier: “O-7” appears in upper left hand corner.