Lieutenant Valentine Wood, Leonidas, to Rear Admiral Albert P. Niblack, Commander, United States Patrol Squadron Based at Gibraltar
U. S. S. Leonidas, Tender,
Squadrons Four and Five,
Submarine Chaser Force.
18th May, 1918.
From: Lieutenant V. Wood, U. S. NAVY.
To : Commanding Officer, (Flotilla Commander.)
SUBJECT: Attack on submarine and subsequent happenings.
1. At 1:45 p.m. while sweeping about one mile off shore in Catalin [i.e., Catalan] Bay, Spain, a periscope wake was seen astern, distant 1/8 of a mile. The 9th Division of Chasers consisting of the S.C. 338, 147, and 227, immediately went ship’s right and headed for this wake. At about the middle of our turn I saw the periscope itself come up and jet of air come out from the upper part. The division headed over to the spot where the periscope was last seen and a depth charge dropped by the S.C. 338, and another by the S.C. 227, almost together. The division then swept the area bombed, but aside from a small quantity of oil and floating oily waste, nothing was seen of the submarine.1
2. At 8:15 p.m. while sweeping one mile off shore in Sardinia Bay, the S.C. 147 reported sounds of hammering and requested permission to sweep inshore. The listener on board the S. C. 338, later by five minutes, picked up these sounds on approximately the same bearing. The division headed inshore sweeping but the noises ceased.
3. At 8.30 several small boats and two launches were seen heading into Sardinia Bay.
4. At 11:20 sounds of a motor charging were heard on deck, while at the same time, a gasoline engine was heard ashore. There were at this time, three lights visible at the other extremity of the bay with a green light or flare near the Westernmost. The division headed into the bay. When at a distance of about one half mile off shore, all lights suddenly went out. The Division proceeded toward the direction of the noise which ceased when we were about 200 yards off shore.
5. At 11:40 the listener on the tubes of the S.C. 147 and 338 both reported sounds of tapping under water. Stood off shore about one mile and then worked in again. The tapping became louder. At 11:45 the listener reported that the tapping seemed to come from several distances. The S.C. 147 also reported different bearings of the tapping. At 11:50 I went below and took over tubes, made out that the tapping was systematic and that the senders were making T I I,2 at intervals of about four seconds. The sounds resembled those made by a hammer upon a steel plate under water. Headed inshore of tappings and worked out to sea with them. All tappings were synchronous at same time heard propeller sound. When off shore about three miles since we saw that we were approaching another division of chasers, turned around and came in. At 12:10 felt depth charge explode in direction of division of sub-chasers we had been heading previously – this was Southwest.
6. At 12:45 headed into coast again and when about one mile off shore, lights were all extinguished. Ran in further and stopped to listen. At 12:50 listener again reported tapping. Ran into about 1/8 of a mile off shore and heard one series of tapping coming from shore, while there almost together ever coming nearer from the westward. Went below and listened by bearings of five degrees. The taps inshore were making “I” (continental) while those off shore were making “T I I2 (continental). Headed to the Southward again and followed noises to eastward, when we approached another division. At about 2:30 turned around and came toward shore once more, picked up tappings again approaching from westward. Stood well inshore and tappings there ceased and then ran out toward approaching noises. Kept almost over sounds for ten minutes at listening intervals of three minutes and then drove them in an East by Southerly direction. Left them when we approached another division as formerly. At 3:00 heard another depth charge explode from direction were heading.
7. The conclusion drawn from the above observations are:-
(a) That a system of lights and signals is operated from Sardinia Bay from the two Spanish block houses, to the westward and to the eastward.
(b) That enemy submarines are able to communicate by submarine oscillator and manoeuvre the same.
(c) That the three submarines were later picked up were called over by distress signals sent out by the one, on bottom, inshore.
(d) That the following are signals for manoeuvres “I” and “T I I” continental code with a hard rap to represent the dash and a light one for a dot.
Source Note: D, DNA, RG 45, Entry 520, Box 387.
Footnote 1: No German submarines were sunk on this date.
Footnote 2: This report goes on to indicate that this is some sort of code, but its meaning is unknown.
