The story of the destruction of Koenigsberg by the twin monitors Severn and Mersey in the Rufigi Delta, has an interest that far transcends the intrinsic military importance of depriving the enemy of a cruiser already useless in sea war. For the narrative of events will bring to our attention at once the extreme complexity and the diversity of the tasks that the Royal Navy in war is called upon to discharge. It is worth examining in detail, if only to illustrate the novelty of the operations which officers, with no such previous experience, may at any moment be called upon to undertake, and the extraordinary combination of patience, courage, skill, and energy with which when experience at last comes, it is turned to immediate profit. The incident possesses, besides, certain technical aspects of the very highest importance. For it gives in its simplest form perfect examples of how guns should not and should be used when engaged in indirect fire, and by affording this illuminating contrast, is highly suggestive of the progress that may be made in naval gunnery when scientific method is universally applied. The incident, then, is worth setting out and examining in some detail, and there is additional reason for doing this, in that the accounts that originally appeared were either altogether inaccurate or so incomplete as to be misleading. First, then, to a narrative of the event itself.

120 Koenigsberg was a light unarmoured cruiser of about 3,400 tons displacement, and was laid down in December 1905. She carried an armament of ten 4.1-inch guns, and was protected by a 2-inch armoured deck. The Germans had begun the construction of vessels of this class about seven years before with Gazelle, which was followed in the next year by Niobe and Nymphe, and then by four more—including Ariadne, destroyed by Lion in the affair of the Heligoland Bight—which were laid down in 1900. Two years later came the three Frauenlobs, and the Bremen class—five in number—succeeded these in 1903–4. In 1905 followed Leipzig, Danzig, and finally the ship that concerns us to-day. All these vessels had the same armament, but in the six years the displacement had gone up 1,000 tons. The speed had increased from 21? knots to about 24, and the nominal radius of action by about 50 per cent. Koenigsberg was succeeded by the Stettins in 1906–7, the two Dresdens in 1907–8, the four Kolbergs in 1908–9, and the four Breslaus in 1911. Karlsruhe, Grodenz, and Rostock were the only three of the 1912–13 programmes which were completed when the war began. The process of growth, illustrated in the advance of Koenigsberg over Niobe, was maintained, so that in the Karlsruhe class in the programme of 1912, while the unit of armament is preserved, we find that the number of guns had grown from ten to twelve; the speed had advanced from 23? to 28 knots, and the displacement from 3,400 to nearly 5,000 tons. As we know now, in the Battle of Jutland we destroyed light cruisers of a still later class in which, in addition to every other form of defence, the armament had been changed from 4.1-inch to 6.7 guns.

Koenigsberg, on the very eve of the outbreak of war, was seen by three ships of the Cape Squadron off Dar-es-121Salaam, the principal port of German East Africa. She was then travelling due north at top speed, and was not seen or heard of again until, a week later, she sank the British steamer City of Winchester near the island of Socotra. There followed three weeks during which no news of her whereabouts reached us. At the end of the month it was known that she had returned south and was in the neighbourhood of Madagascar. At the end of the third week in September she came upon H.M.S. Pegasus off Zanzibar. Pegasus was taken completely unawares while she was cleaning furnaces and boilers and engaged in general repairs. It was not possible then for her to make any effective reply to Koenigsberg’s sudden assault, and a few hours after Koenigsberg left she sank. Some time between the end of September and the end of October, Koenigsberg retreated up one of the mouths of the Rufigi River, and was discovered near the entrance on October 31 by H.M.S. Chatham. From then onwards, all the mouths of the river were blockaded and escape became impossible. Her captain seemingly determined, in these circumstances, to make the ship absolutely safe. He took advantage of the high water tides, and forced his vessel some twelve or more miles up the river. Here she was located by aeroplane at the end of November. Various efforts had been made to reach her by gunfire. It was asserted at one time that H.M.S. Goliath had indeed destroyed her by indirect bombardment. But there was never any foundation for supposing the story to be true, and if in the course of any of these efforts the ship suffered any damage, it became abundantly clear, when she was finally engaged by the monitors, either that her armament had never been touched, or that all injuries had been made good.

122 The problems which the existence of Koenigsberg propounded were: first, Was it a matter of very urgent moment to destroy her? Second, How could her destruction be effected? The importance of destroying her was great. There was, of course, no fear of her affecting the naval position seriously if she should be able to escape; but that she could do some, and possibly great, damage if at large, the depredations of Emden in the neighbouring Indian Ocean, and of Karlsruhe off Pernambuco, had proved very amply indeed. If she was not destroyed then, a close blockade would have to be rigidly maintained, and it was a question whether the maintenance of the blockade would not involve, in the end, just as much trouble as her destruction. Then there was a further point. Sooner or later, the forces of Great Britain and Belgium would certainly have to undertake the conquest of German East Africa. While Koenigsberg could not be used as a unit for defence, her crew and armament might prove valuable assets to the enemy. Finally, there was a question of prestige. The Germans thought that they had made their ship safe. If the thing was possible, it was our obvious duty to prove that their confidence was misplaced.

If the ship was to be destroyed, what was to be the method of her destruction? She could not be reached by ship’s guns. For no normal warship of superior power would be of less draught than Koenigsberg, and unless the draught were very materially less, it would be quite impossible to get within range, except by processes as slow and laborious as those by which she had attained her anchorage. Was it worth while attempting a cutting-out expedition? It would not, of course, be on the lines of the dashing and gallant adventures so brilliantly drawn for us by Captain Marryat. The boats would proceed under123 steam and would not be rowed; they would not sally out to board the enemy and fight his crew hand to hand, but to get near enough to start a torpedo at him, discharged from dropping gear in a picket boat. To have attempted this would have been to face a grave risk, for not only might the several entrances be mined, but the boats clearly would have to advance unprotected up a river whose banks were covered with bush impenetrable to the eye. The enemy, it was known, had not only considerable military forces in the colony, but those well supplied with field artillery. And there were on board Koenigsberg not only the 4.1-inch guns of her main armament, but a considerable battery of eight or perhaps twelve, 3-inch guns—a weapon amply large enough to sink a ship’s picket boat, and that with a single shot. An attack by boats then promised no success at all, for the excellent reason that it would be the simplest thing on earth for the enemy to defeat it long before the expedition had reached the point from which it could strike a blow at its prey.

There was then only one possible solution of the problem. It was to employ armed vessels of sufficient gun-power to do the work quickly, and of shallow enough draught to get to a fighting range quickly. If the thing were not done quickly, an attack from the masked banks might be fatal. If the guns of such a vessel were corrected by observers in aeroplanes, they might be enabled to do the trick. Fortunately, at the very opening of the war, the Admiralty had purchased from the builders three river monitors, then under construction in England for the Brazilian Government. They drew but a few feet. Their free board was low, their centre structure afforded but a small mark; the two 6-inch guns they carried fore and aft were protected by steel shields. They had been employed124 with marked success against the Germans in their first advance to the coast of Belgium. When the enemy, having established himself in the neighbourhood of Nieuport, had time to bring up and emplace long-range guns of large calibre, the further employment of these river monitors on this, their first job, was no longer possible. For the moment, then, they seemed to be out of work, and here was an undertaking exactly suited to their capacity. It was not the sort of undertaking for which they had been designed. But it was one to which, undoubtedly they could be adapted. Of the three monitors Mersey and Severn were therefore sent out to Mafia Island, which lies just off the Rufigi Delta and had been seized by us early in the proceedings.

The first aeroplanes available proved to be unequal to the task, because of the inadequacy of their lifting power. The atmosphere in the tropics is of a totally different buoyancy from that in colder latitudes, and a machine whose engines enable it to mount quite easily to a height of 4,000 or 5,000 feet in Northern Europe, cannot, in Central Africa, rise more than a few hundred feet from the ground. New types of machines, therefore, had to be sent, and these had to be tested and got ready for work. For many weeks then, before the actual attack was undertaken, we must picture to ourselves the Island of Mafia, hitherto unoccupied and indeed untouched by Europeans, in the process of conversion into an effective base for some highly complicated combined operations of aircraft and sea force. The virgin forest had to be cleared away and the ground levelled for an aerodrome. The flying men had to study and master machines of a type of which they had no previous experience. The monitors had to have their guns tested and their structural arrangement altered and strengthened125 to fit them for their new undertaking. And indeed preparing the monitors was a serious matter. The whole delta of the Rufigi is covered with forest and thick bush—nowhere are the trees less than sixty feet high, and in places they rise to nearly three times this height. To engage the Koenigsberg with any prospect of success, five, six, or seven miles of one of the river branches would certainly have to be traversed. There was, it is true, a choice of three mouths by which these vessels might proceed. But it would be almost certain that the different mouths would be protected by artillery, machine guns, and rifles, and highly probable that one or all of them would be mined. The thick bush would make it impossible for the monitors to engage any hidden opponents with sufficient success to silence their fire. And obviously any portion of the bank might conceal, not only field guns and riflemen, but stations from which torpedoes could be released against them. It was imperative therefore, to protect the monitors from such gun fire as might be encountered, and to take every step possible to preserve their buoyancy if a mine or torpedo was encountered.

The Trent had come out as a mother ship to these two unusual men-of-war, and from the moment of their arrival, she became an active arsenal for the further arming and protection of her charges. Many tons of plating were laid over their vulnerable portions—the steering gear, magazines, navigating bridges, etc., having to be specially considered. The gun shields were increased in size, and every precaution taken to protect the gunners from rifle fire. Where plating could not be added, sandbags were employed. By these means the danger of the ship being incapacitated, or the crew being disabled by what the enemy could do from the bank, was reduced126 to a minimum. These precautions would not, of course, have been a complete protection against continuous hitting by the plunging fire of Koenigsberg’s artillery. The more difficult job was to protect the ships against mines and torpedoes. Their first and best protection, of course, was their shallow draught. But it was not left at that; and most ingenious devices were employed which would have gone a fair way to keep the ships floating even had an under-water mine been exploded beneath the bottom. At intervals, between these spells of dockyard work, the monitors were taken out for practice in conjunction with the aeroplanes. Mafia Island, which had already served as a dockyard and aerodrome, was now once more to come in useful as a screen between the monitors and the target. The various operations necessary for indirect fire were carefully studied. Gun-layers, of course, cannot aim at a mark they cannot see. The gun, therefore, has to be trained and elevated on information exteriorly obtained, and some object within view—at exactly the same height above the water as the gun-layer—has to be found on which he is to direct his sight. The gun is now elevated to the approximate range, a shot is fired and the direction of the shot and the distance upon the sight are altered in accordance with the correction. At last a point of aim for the gun-layer, and a sight elevation and deflection are found, and his duty then is to fire away, aiming perhaps at a twig or a leaf a few hundred yards off, while the projectile he discharges falls upon a target four, five, or even six miles off.
THE FIRST ATTEMPT

At last all was ready for the great attack. The crew had all been put into khaki, every fitting had been cleared127 out of the monitors; they had slipped off in the dark the night before and were anchored when, at 3:30 in the morning, all was ready. I will now let a participant continue the story:

“I woke up hearing the chatter of the seedy boys and the voice of the quartermaster telling someone it was 3:20. I hurried along to my cabin and was dressed in three minutes; khaki shirt, trousers, shoes, and socks. A servant brought me a cup of cocoa and some biscuits, and I then gathered the waterbottle and a haversack of sandwiches, biscuits, brandy flask, glass phial of morphia, box of matches, cigarettes, and made my way up to the top.

“It was quite dark in spite of the half moon partly hidden by clouds, and men wandering about the docks putting the last touches. It was impossible to recognize any one as all were in khaki and cap and helmet. By 3:45 all were at general quarters and at —— we weighed and proceeded. Both motor-boats were towing, one on either side amidships. Two whalers anchored off Komo Island, and burning a single light each, acted as a guide to the mouth. We soon began to see the dim outline of the shore on the right hand, and —— declared he could distinguish the mouth. There were four of us in the top. We arranged ourselves conveniently, —— and —— taking a side each to look out. The Gunnery Lieutenant took the fore 6-inch and starboard battery. I had the after 6-inch and port battery. I dozed at first for about ten minutes, but as the island neared woke up completely. We had no idea what sort of reception we should have, and speculated about it. It was quite cold looking over the top. The land came nearer and nearer. We were going slow, sounding all the way. On the starboard side it128 was quite visible as the light grew stronger and stronger. Suddenly when we were well inside the right bank we heard a shot fired on the starboard quarter, but could not see the flash. Then came another, but only at the third did we see where it came from. It was a field-gun on the right, but we had already passed it, and both it and the pom-pom were turned on the Mersey astern of us.

“At least nothing fell near us. It was still not light enough for us to judge the range, but as the alarm had been given we opened fire with the 3-pounders, starboard side, at the fieldgun. As we came up to the point on the port side I trained all the port battery on the foremost bearing, and opened fire as soon as the guns would bear. We were now going pretty well full speed. Some snipers were hidden in the trees and rushes, and let us have it as we went past. The report of their rifles sounded quite different from ours, but we were abreast before they started, and were soon past. It was just getting light. We were inside the river before the sun rose, and went quite fast up. It was just about dead low water as we entered, neap tide. The river was about 700 yards broad. The banks were well defined by the green trees, mangroves probably, which grew right down to the edges. The land beyond was quite flat on the left, but about four miles to the right rose to quite a good height—Pemba Hills. Here and there were native huts well back from the river; we could see them from the top though they were invisible from the deck. On either side as we passed up were creeks of all sorts and sizes at low tides, more of them on the port side than on the starboard. As we passed, or rather before, we turned the port or starboard batteries on them and swept either side. The gun-layers had orders to fire at anything that moved or129 looked suspicious. We controlled them more or less, and gave them the bearings of the creeks. —— was in charge of those on deck, and the crews themselves fired or ceased fire if they saw anything or had sunk anything. We checked them from time to time as the next creek opened up. We were looking ahead most of the time, but I believe (from ——) we sank three dhows and a boat. Whether they were harmless or not, I don’t know, but it had to be done as a precaution. We made a fine noise, the sharp report of the five 3-pounders and one 4.7 and the crackle of the machine guns (four a side) must have been heard for miles. The Hyacinth, the tugs, the Trent, the Weymouth, and other odd craft were demonstrating at the other mouths of the Rufigi, and we could hear the deep boom of their 6-inch now and then. I believe, too, that there was a demonstration by colliers, etc., off Dar-es-Salaam at the same time.

“I had thought that the entry would be the worst part, but it was not much. A few bullets got us and marked the plates or went through the hammocks but no one was hit, and as our noise completely drowned the report of their rifles I doubt if many knew we were being sniped. The forecastle hands knew all about it later on. As they hauled in the anchor or let it go they nipped behind any shelter there was, and could hear the bullets zip-zip into the sandbags. The Mersey astern was blazing away into the banks just as we were. There was probably nothing in most of the creeks—but we did not know it then.

“It was 6:30 o’clock by the time we reached ‘our’ island, where the river branches into three, at the end of which we were to anchor. We were steering straight up the middle of the stream, and then swung slowly round to port, dropped the stern anchor, let out seventy fathoms130 of wire, dropped the main anchor, went astern, and then tightened in both cables, so that we were anchored fast bow and stern. As soon as we steadied down a bearing was taken on the chart and the gun laid—about eight minutes’ work. It was then found that, thanks to the curious run of the current, the fore 6-inch would not bear, and we had to take up the bow anchor and let it go again to get us squarer towards the Koenigsberg.

“We could see the aeroplane right high up, and received the signal ‘open fire.’ We were not quite ready, however. From the moment when we turned to port to take up our firing position to the time we were finally ready and had laid both guns, occupied about twenty minutes. The Koenigsberg started firing at us five minutes before we were ready to start. Their first shot (from one gun only) fell on the island, the next was on the edge of it, and very soon she was straddling us. Where they were spotting from I don’t know, but they must have been in a good position, and their spotting was excellent. They never lost our range. The firing started, and for the next two hours both sides were hard at it. I don’t believe any ship has been in a hotter place without being hit. Their shooting was extraordinarily good. Their salvoes of fire at first dropped 100 short, 50 over, 20 to the right—then straddled us—then just short—then all round us, and so on. We might have been hit fifty times—they could not have fired better; but we were not hit at all, though a piece of shell was picked up on the forecastle.

“The river was now a curious sight, as dead fish were coming to the surface everywhere. It was the Koenigsberg’s shells bursting in the water which did the damage, and there were masses of them everywhere—mostly small ones.

131 “We were firing all the time, of course. I attended to the W/T, and passed the messages to the Gunnery Lieutenant, who made the corrections and passed them to the guns. —— watched the aeroplane and the banks as far as possible. —— attended to the conning tower voice pipe. We got H. T. fairly soon, and the Koenigsberg’s salvoes were now only four guns. We heard the boom; then before it had finished came whizz-z-z-z or plop, plop, plop, plop, as the shells went just short or over. They were firing much more rapidly than we, and I should think more accurately, but if I had been in the Koenigsberg I should, probably, have thought the opposite! All this time the 3-pounders had occasional outbursts as they saw, or thought they saw, something moving. Occasionally, too, the smoke and fumes from our funnel drifted across the top, and it was unpleasant for a minute or two. We could see now where the Koenigsberg was, and the smoke from her funnels, or that our shells made. She was firing salvoes of four with great rapidity and regularity, about three times a minute, and every one of them close. Some made a splash in the water so near that you could have reached the place with a boat-hook.

“At 7:40 (so I am told, as, though I tried I lost all count of time) a shell hit the fore 6-inch of the Mersey and a column of flame shot up. Four were killed and four wounded. Part of the shield was blown away. Only one man remained standing, and after swaying about he fell dead. One had his head completely blown off. Another was lying with his arm torn out at the shoulder, and his body covered with yellow flames from a lyddite charge which caught. The R. N. R. Lieutenant in charge was knocked senseless and covered with blood, but had only a scratch on the wrist to show for it. The132 gun-layer had an extraordinary escape, and only lost three fingers. Two men escaped as they had just gone forward to weigh the anchor. A burning charge fell into the shell room below, but was fortunately got out. Another shell burst in the motor-boat alongside the Mersey and sank it. One burst in the water about a foot from the side, and we thought she was holed. The Mersey captain then wisely moved and went down river, taking up a position of 1,000 yards down, by the right bank (looking at the Koenigsberg). She started in again with her after gun, the other being disabled. For an hour and twenty minutes we went on, and the Koenigsberg’s salvoes came steadily and regularly back, as close as ever. It seemed as if it could not go on much longer. We registered four hits, and the salvoes were reduced from four to three, and later to two, and then to one gun. Whether we had reduced them to silence or whether the Koenigsberg’s crew left them and saved ammunition it is impossible to say.

“The aeroplane spotting had been fair, but now someone else started in and made the signals unintelligible. Then we got spotting corrections from two sources—both differing widely. Finally, the aeroplane made “W. O.” (going home). We weighed and took up station again by the Mersey. She moved to get out of our way, and when another aeroplane came we started it again. The replies from the Koenigsberg were not so frequent, and nothing like so accurate. It was as if they could not spot the fall of shot. The aeroplane soon disappeared, and as we could see the mast of the Koenigsberg (I could only see one personally) and a column of smoke which varied in thickness from time to time, we tried to spot for ourselves. It was useless as, though we saw the burst133 (or thought we did) in line with the masts, we did not know whether they were over or short. Finally, we moved up the river nearer, still keeping on the right side, and set to work again.

“There were two cruisers—Weymouth and Pyramus, I think—at the mouth. The Weymouth did a good deal of firing at Pemba Hill and a native village close to us, where there might be spotters.

“When we reached W/T corrections now they were of no use. Most were ‘did not observe fall of shot,’ or 600 short. We went up 1,000, but still received the same signal—whether from the aeroplane or the Koenigsberg, I don’t know. It was most confusing. We crept up the scale to maximum elevation. Finally, we moved up the river again, but put our nose on the mud. We were soon off, and moved over to the other side and continued firing, spotting as well as we could (but getting nothing definite) till four o’clock, when we packed up and prepared to come out. We swept the banks again on both sides, but only at the entrance was there opposition. We made such a noise ourselves that we drowned the report of any shots fired at us. Two field-guns made good practice at us from the right bank (looking at the Koenigsberg). One came very close indeed to the top—so much so that we all turned to look at each other, thinking it must have touched somewhere. One burst about five yards over us. Another burst fifteen yards from the Mersey, and a second hit her sounding boom. We could see the white smoke of the discharge and fired lyddite, but the object was invisible.

“It was getting dusk as we got outside at full speed. The secure was sounded at about 4:45. We had been at general quarters for thirteen hours, and eleven of them134 had been under fire. Outside the other ships were waiting for us near Komo Island, and we went straight alongside the Trent. Each ship cheered us as we passed. The Mersey put her wounded on the Trent, and then pushed off to bury the dead.

“Tuesday, July 6, was the day of the first attempt, and one of the worst I ever had or am likely to have. We were at our stations from 3:45 A.M. till 4:45 P.M., and eleven hours of that were under fire. The engine-room people were not relieved the whole time, and they were down there the whole time in a temperature of 132°-135°! It was hot up in the top—but child’s play to the engine room.”
SUCCESS

On July 11 the second attack was made, but made in a very different manner from the first. Once more let us allow the same writer to complete the story:

“We went to General Quarters at 10:40 A.M. and were inside the entrance by 11:40. How well we seemed to know the place! I knew exactly where the beastly field guns at the mouth would open fire and exactly when they would cease—as we pushed in, and so if their shots went over us they would land on the opposite bank among their own troops. Very soon came the soft whistle of the shell, then again and again—but we were nearing the entrance and they turned on the Mersey. They hit her twice, wounding two men and knocking down the after 6-inch gun crew—none was hurt, however. I spotted a boat straight ahead making across the river for dear life—they may only have been natives, but we fired the 6-inch at them till they leapt ashore and disappeared.

“Up the river we went. I knew each creek, and almost135 each tree, and as before we blazed into them just before we passed.

“We left the Mersey at the place where we anchored last time in the hope that she would draw the Koenigsberg’s fire and leave us a free hand. The Koenigsberg, however, fired one salvo at her and then for the rest of the day concentrated on us. She was plugging us for seventeen minutes before we could return her fire. The salvoes of four were dropping closer than ever if possible and afterwards almost every man in the ship found a bit of German shell on board as a souvenir. They were everywhere—in the sandbags, on the decks, round the engine room—but not a soul was even scratched!

“We went on higher up the river than last time and finally anchored just at the top of ‘our’ old island. As the after 6-inch gun’s crew were securing the stern anchor two shells fell, one on either side, within three feet of the side, and drenched the quarter-deck. It was a very critical time. If she hit us we were probably finished, and she came as near as possible without actually touching. I had bet 5s. that she would start with salvoes of four guns, and I won my bet. They............