August 2, RN Submarine D4, Course 140, Speed 2 knots, Periscope depth 0620 hours
At the North end of the German Horn’s Reef minefield
It appeared to the skipper of the D4 (See Note 1) – Lieutenant Charles Moncreiffe – that all his patience had been rewarded. For a couple of days, the D4 had stood off the minefields watching the minelayers, renew and revise the minefields. Now it looked like one of them had run aground in the shallows. Here was a chance to torpedo something.
The problem was that the grounded minelayer was back in the mine field a bit. Having watched the minelayers for a while Moncreiffe had a feeling about where the edge of the minefield would be and really did not want to try his luck in a minefield.
Nothing else around except a plume to the south.
Technically in range of his Mk. VIII torpedoes but just barely. Even a sitting duck at this range was a low-percentage shot. Moncreiffe consulted his charts. If he ran the D4 about a mile to the west, he could cut about 800 yards off the shot and still stay out of the minefields.
“Come left to 090”
The minelayer did not look like she was going to go far soon.
A half hour later Moncreiffe reckoned he had gone the requisite mile and raised his periscope.
Again Moncreiffe consulted his charts. It seemed the D4 had drifted a little north but that was no problem. The big problem was that the D4 was now in the shallows as well. Periscope depth was about as deep as he could go unless he moved about 400 yards west if his reckoning of his position was right.
“Come right to 175”
The minelayer was still there, but the plume to the south was much bigger now and partially obscured by the minelayer. Apparently the minelayer was trying furiously to get off the beach and was pouring out smoke.
His boat steadied out on 175 and it was now or never. In a few minutes, he would be in the minefield.
“Ready bow tubes. Set for five feet”
“Bow tubes ready”
“Open outer doors”
“We have a solution”
“Close outer doors” (See Note 2)
“Come right to 280”
Unbeknownst to Moncreiffe at this time, British torpedoes had a number of technical problems. One of those problems bit this salvo.
The first torpedo ran too deep and struck a gravel bar. It did not hit square enough to explode but rather deflected upward, broached, then ran deep trying to find five feet and hit another bar and this time exploded.
The second torpedo managed to run about at five feet but was a bit off-target to start with. The explosion of the first torpedo, which was slightly ahead of it deflected it another few degrees to the right and she passed well astern of the grounded minelayer.
August 2, German Torpedo Boat S69, Course 355, Speed 15 knots 0658 hours
Just west of grounded minelayer
The S69 had been dispatched to try to help the grounded minelayer Bielefield around 0300. It was a short trip, but one did not mindlessly charge through minefields, even if one thought he was in the clear channel at night. Around dawn the S69 had sped up to fifteen knots and had the Bielefield in sight.
Just before he was about to pass astern of the Bielefield, the Kommandant, Oberleutnant Grieg was about to order a reduction in speed, preparatory to approaching the Bielefield to see if he could help get her off the ground, but something to the north caught his eye and a few seconds later came an explosion.
“Torpedo track off the starboard bow”
Grieg picked up the track.
“Hard right rudder! Come to 015!”
“Torpedo one, set to four meters”
The quick side step neatly dodged the torpedo which passed harmlessly to the west.
“Come left to 350 Full speed ahead!”
Grieg intended to run the back bearing and hoped to ram the submarine. The water was shallow and although the S69 only drew about a meter and three quarters, maybe he would hit the submarine.
About a minute after steadying up on his northerly course, Grieg ordered her to a heading of 330 to unmask his torpedo tube. Like other ships, the S69 had been saddled with the short-range C35/91 torpedoes, and like everyone else, Grieg became prolifigate in his use of them. The idea was: “Shoot them all and we’ll be rid of them.”
At what he reckoned was 300 yards…
Old and obsolete as it was, the C35/91 dutifully ran back up the dissipating torpedo trail from the enemy submarine at almost exactly four meters depth, but because the submarine had turned for deeper waters, it missed and ran out of fuel and fell to the sea floor.
August 2, D4, Course 280, Speed 2 knots, Periscope depth 0701 hours
At the North end of the German Horn’s Reef minefield
No hydrophones were necessary to hear the distinctive sound. The sound got closer then farther then quit, but now there was another problem. The crew could hear the sounds of the screws of a German vessel getting closer.
Moncreiffe, lacking any sort of directional equipment had to go on intuition. He knew he was going more or less west and the Hun had to be coming more or less north.
“Hard right rudder! Come to 000”
He would “comb the wake” of the German as he had “combed the wake” of the torpedo.
The helmsman had just put the rudder over when the collision came. Actually, “collision” was too lurid a word. One reason the TB1892 boats were used in support of minelayers was their shallow draft. This far north, their draft offered a lot of clearance to the minimum depth of the mines. This gave them a degree of safety, but made these boats lousy as submarine rams. If the submarine had been twenty feet further west (or twenty feet further east) the S69 would have missed completely. All the S69 succeeded in doing was clipping the periscope and radio mast (See Note 3) of the D4 off cleanly, and in the process punched a small hole in her own hull.
All the same, the submarine did a quick fifteen degree roll that knocked every one off their feet. Moncreiffe lay on the deck and felt cold water. He got back up and saw the periscope seal gland was leaking. Quickly, a crewman shouldered him aside and used a small hammer and punch to drive a piece of oakum rope into the leak. The leak stopped.
Apparently nothing else was hurt.
August 2, German Torpedo Boat S69, Course 330, Speed 22 knots 0702 hours
Just north of the submarine
“Set torpedo two for four meters”
“Hard left rudder Come to 160”
“Gun! Open fire”
POP POP POP POP
The 5 cm gun began uselessly tapping away at the supposed location of the submarine.
“Sir, we are open to the sea in the forward compartment. It looks like about a ten or twelve centimeter hole. The men are rigging an emergency plug.”
The torpedo boat swung around and the torpedo tube bore on the spot of the collision.
“Come left to 200”
“Sir, the plug won’t hold at this speed. We have to slow down.”
“All ahead slow”
As before, the torpedo missed.
The boat, now noticeably down by the head, slowed quickly to eight knots. At this speed the men got the plug to hold and the pumps began making headway against the flooding.
Grieg sent off a wireless report, including an estimation that extracting the Bielefield would require a tug. Within a few minutes he was instructed to return to base for repairs. Other ships would be dispatched to help the Bielefield.
August 2, D4, Course 300, Speed 3 knots, Depth 30 feet 0930 hours
Northwest of the entrance to the Horn’s Reef minefields.
Moncreiffe had to surface. The quick repairs that held at periscope depth leaked like mad at a safer thirty foot depth. Better repairs needed the boat to be surfaced.
She surfaced. The grounded minelayer was still in distant sight but the torpedo boat must have been damaged in the exchange as well and there was just a smudge of a plume on the southern horizon.
“All ahead standard”
Speed and battery charging.
The banging they had heard while submerged was not the periscope. The periscope was sheared cleanly off. What was banging was the remnants of the wireless mast.
“Get Sparks up here”
The wireless operator took one look and told Moncreiffe the mast was a write-off. The remnant was too short and could not either send or receive on the wavelengths his wireless operated on. Moncreiffe had the crew cut off the rest of the wireless mast.
“Come left to 240”
He’d have to return to Harwich for repairs. With no periscope and leaking damage, and only one more torpedo, the D4 was not much of a combatant anymore.
1.Shortly after being commissioned, the D4 took Sir Winston Churchill, Roger Keyes and the future King on a submerged excursion across Plymouth harbor.
2.Like other submarines of this vintage, the D4 carried no torpedo reloads.
3.“D” class submarines used a separate wireless mast that had to be raised and lowered before use. This turned out to be a clumsy arrangement and was never used again.