The Secret Capture

by Stephen Roskill

  But the organisation of the initial escorts for OB.318 was not the end of the preparations which the Western Approaches Command had to make. No. 15 Group of Coastal Command had been given the course which the convoy would take, and the orders for its departure, when they were issued by the Admiralty; and a representative of the Group was always on duty in the operations room at Western Approaches Command Headquarters. Thus the Royal Air Force was able to make its own plans to meet the Admiralty’s needs by providing the convoy with air escort until it passed outside the range of the home-based aircraft. At the time with which we are dealing this was only about 600 miles; but other aircraft flying from Iceland bases, which formed part of No. 15 Group, would take over the responsibility when the convoy came within their range. A second important measure was that Admiral Noble detailed the 3rd Escort Group under Commander A. J. Baker-Cresswell, which had recently arrived in Reykjavik from another convoy operation, to relieve Bockett-Pugh’s group at a rendezvous some 150 miles south of Reykjavik in Iceland on the evening of the 7th May. We will return to the composition of the 3rd Escort Group, and its actions while escorting OB.318 later; for we must now look at the merchantmen forming the convoy a little more closely. Of the 42 ships originally nominated for OB.318 five were not ready in time; but the Dutch ocean tug Zwarte Zee was added, making 38 ships in all. Their total tonnage was 204,811 Gross Register Tons, and no less than six different nations were represented in the convoy. The Dutch and Norwegians each owned three of the ships, one was Swedish (the only neutral ship present) another was of Belgian registry, and Greece was also represented by one ship. All the remaining twenty-nine belonged to British shipowners, or were sailing under charter to one of them or to the Ministry of Transport. In size the ships in the convoy varied from the tiny short-sea trader Atlantic Coast of 890 tons to the China Mutual Steam Navigation Company’s fine passenger-cargo steamer Ixion of 10,263 tons. No less than five of the convoy were tankers, bound for the West Indian oil ports.1

  The speeds of which different ships were theoretically capable varied from 9 to 12½ knots; but the speed of the convoy would, of course, have to be the speed of the slowest ship, and it was unlikely that more than 8 knots could be maintained while steaming in formation. No less than sixteen of the convoy were in ballast for the outward journey, having discharged their cargoes of food, war stores or raw materials in Britain and been unable to find a return cargo. The loaded ships had a wide variety of cargoes, such as clay, coal, chalk and wood pulp for American or Canadian ports, military stores for West Africa or the Middle East, and general cargoes for the United States. The latter included specially valuable exports, such as whisky, which we continued to send to the United States in order to earn precious dollars. The final destinations of the merchantmen, for which they would steer as soon as the convoy dispersed, covered almost the whole world. Though several were bound only for the east coasts of America and Canada, others were to round the Cape of Good Hope, or pass through the Panama Canal into the Pacific, there to discharge what they carried and to load again with Britain’s most urgent needs. Buenos Aires, Freetown, Durban, Curaçao, Jamaica, Lagos, and many other ports were shown as the final destination of one or more ships. The convoy was indeed a remarkable epitome of the world-wide seaborne traffic on which our peacetime prosperity depends, and which, in time of war, keeps our factories in production and our fighting services supplied with all their multifarious needs. As evidence of the dangers of the service on which they were now engaged, the individual distinguishing marks of the various lines were no longer worn, and most ships were painted a nondescript grey. Even their names had been obliterated, and all except the neutral Swedish ship were defensively armed. Twenty-eight of them carried an old naval 4-inch gun mounted at the stern for defence against a pursuing submarine, while nine had 12-pounder dual-purpose (anti-aircraft or low-angle) weapons. Recent enemy air attacks on our merchantmen had caused the Admiralty to provide some form of anti-aircraft gun or device to as many ships as possible, desperately short though we were of all such weapons. Ten of the convoy had received 40 mm. Bofors guns, which actually belonged to the Army and were manned by military crews drawn from a recently organised formation known as the Maritime Anti-Aircraft Regiment. These guns, together with their crews, were generally removed at the first convenient port of call, and then transferred to a homeward-bound ship. But, in addition to the Bofors, all ships carried from two to six light machine-guns, and eighteen of them were fitted to fly kites on wire cables—a device which we had found useful for scaring off low-flying aircraft. Each ship carried a number of trained men, most of whom were Naval or Royal Marine pensioners or reservists, drawn from the Admiralty’s world-wide Defensively Equipped Merchant Ship (D.E.M.S.) organisation; and they provided the key numbers at the guns. But the Merchant Navy officers and men had themselves been receiving an increasing amount of training in gunnery, and in most ships they were capable of using at least the lighter weapons at a moment’s notice. We had indeed found that, in the conditions which had prevailed since the crisis of June, 1940, a merchant ship had to be prepared to defend herself at all hours of the day or night; and that could only be accomplished by virtually all her deck officers and men being trained to handle and use the weapons provided by the Admiralty.

  The organisation of the convoy, and the plans made for its defence, were discussed at convoy conferences held at Liverpool and in the subsidiary ports before each section sailed. The masters of all the merchantmen were invariably present, as was the Commodore of the convoy, the Senior Officer of the escort, the Naval Control Service Officer in the port, and a representative of No. 15 Group. The Masters of ships had previously received written orders regarding the formation and sailing of the convoy, together with the necessary signal instructions, and at the conference the chairman outlined the plans, and the Commodore gave his intentions should an emergency, such as a submarine contact, arise. Questions were then invited from the ships’ Masters. Sometimes Admiral Noble himself took the chair at the main conference in Liverpool; but more commonly it would be his Chief of Staff, or the Naval Control Service Officer, who fulfilled that function. The atmosphere was entirely informal, and the intimate way in which plans and problems were discussed across the table undoubtedly reinforced the confidence of the Masters that everything possible would be done for the protection of their ships, and that their own problems were sympathetically understood by the Royal Navy.

  In the narrow waters of the Minches the convoy could not steam in its ocean formation, and would therefore proceed in two loosely organised columns. But as soon as it emerged into the Atlantic ships would take up their final stations. Our convoy was actually organised in nine columns, each consisting of four or five ships; and their positions in the convoy were identified by two figure symbols. The first figure was the number of the column, counting from the left of the formation, and the second signified the position of a ship in the column, counting from its head. Thus Number 84 would be the fourth ship in Column 8. This system had been made standard for all convoy operations, and enabled ships to be quickly identified and spoken to. Their peacetime names, though shown on the Convoy Form, now gave place to the more impersonal numbers. The formation and numbering of OB.318 are shown on the diagram at the end of this book. Ships in column were to keep station at two cables (400 yards) distance, while the spaces between columns were normally to be five cables (1,000 yards) if U-boat attacks threatened, but might be shortened to three cables (600 yards) if enemy bombers were the greater danger; for we had found that the closer formation enabled ships to render each other mutual support in the event of air attack. In April, 1941, the practice of zig-zagging in formation, according to a prearranged plan, was abolished for slow convoys. Instead the Commodore would employ “ evasive steering ” to keep his charges clear of waters where U-boats were known or suspected to be lying in wait, or to shake off a shadowing enemy. In addition, if a sudden emergency arose—such as a ship being torpedoed—the whol
e convoy could be turned together 40 degrees at a time in either direction by flag or light signal from the Commodore’s ship, or by siren signal in low visibility.

  The reader will realise that accurate station keeping and safe manoeuvring in formation placed a heavy strain on the Masters and watch officers of the merchantmen, especially in heavy weather. With ships of widely varying size and performance it needed constant vigilance to maintain correct station, and it is not surprising that hair-raising escapes from collision were quite frequent, and serious accidents by no means uncommon. Yet all our experience proved that ships in convoy were, except in the case of those possessed of an outstanding turn of speed, far safer from either submarine or air attack than ships sailing independently; and most Masters, though they disliked convoy with varying degrees of intensity, came to recognise this. The Admiralty and Senior Officers of escort groups did all they could to discourage the practice of straggling astern of a convoy, which was notoriously dangerous; and although the habit was never entirely eradicated it became rarer as the war progressed, and the steady toll taken of ships which broke formation became more widely known. Many convoys made their passages without a ship breaking the formation, and manoeuvred with a precision which called forth the admiration of the escorts. Others did less well, and it was these that were most liable to run into serious trouble.

  The Commodore of OB.318 was Rear-Admiral (Retd.) W. B. Mackenzie, and he and his small signal staff sailed in the 5,108-ton British ship Colonial, owned by the Charente Steamship Company, which was carrying a general cargo to Sierra Leone and Capetown. Her position in the convoy was at the head of Column No. 4. The Vice-Commodore was Captain E. Rees, Master of the British Prince bound for Halifax, and the Rear-Commodore was the Master of the Burma whose destination was Capetown. These two ships were stationed at the heads of Columns No. 2 and 6 respectively, and their Masters would take over responsibility for the convoy if casualties eliminated the more senior officers. Rear-Admiral Mackenzie was one of the gallant band of retired Flag Officers who returned to serve in the Royal Naval Reserve as Commodores of ocean convoys. No less than 21 of them were lost at sea during the war—probably a higher percentage of casualties than was suffered by any other branch of the Service. Mackenzie was born in Dumbartonshire in 1885, joined the Britannia at the age of 14, and specialised in Torpedo as a Lieutenant. At the Battle of Jutland he was serving in the ill-fated battleship Royal Oak, and after the first war he was executive officer of the Emperor of India during a commission which the survivors of her company still look back on happily. As a Captain he commanded several light cruisers and the aircraft carrier Hermes between the wars, and played a big part in organising anti-submarine training and starting a specialist branch in that vital subject while commanding the shore establishment formed for that purpose at Portland. His last appointment was as Director of Torpedoes and Mining in the Admiralty at the time when, in the 1930’s, the reluctance of the government to face the rising truculence of the dictators and provide the funds needed for re-armament was causing the greatest anxieties in Service circles. It was Mackenzie’s lot to try to prepare his branch for the clash which appeared increasingly probable, while denied the means to do so effectively. His strength of character and unshakable calm in face of difficulties or danger made him an ideal man to work with and help the Merchant Navy when, soon after the outbreak of the second war, he was asked to serve as Commodore of convoys.

  Convoy OB.318’s journey started uneventfully on the afternoon of 2nd May. The subsidiary sections all joined up at their appointed times and places, and the passage up the Minches was made in fine weather. As soon as the Liverpool, Milford, Clyde and Loch Ewe sections had cleared harbour the Naval Control Service officers at the ports reported their departure, and also the final destinations and expected dates of arrival of the individual ships. In the Operations Intelligence Centre at the Admiralty and on the plot at Derby House, Liverpool, where Admiral Noble had his headquarters, special symbols indicating the convoy’s position were now in place on the vast wall maps, and strings had been stretched across the ocean to show its intended course. Against the convoy symbols were shown the names of the escorts, and from now onwards a constant watch was kept on the progress of the operation.

  During its northward passage through the coastal waters the convoy was given strong and continuous air escort as long as daylight lasted; for the Germans had recently been making frequent bombing attacks on our inshore shipping, and we also knew that some U-boats were patrolling not very far outside the Hebrides. On 3rd and 4th May four Ansons of No. 48 Squadron, flying from Islay and Stornoway, were continuously with the convoy, and on the latter day they were reinforced by a fighter escort of four Blenheims from No. 248 Squadron, whose base was at Wick in north-east Scotland. That evening, as the convoy rounded the Butt of Lewis, the northern cape of the Hebrides, a night-flying Whitley from Wick patrolled overhead. On arrival it was greeted by a short burst of fire from one of the escort vessels—which fortunately did no damage. It was always difficult to identify friendly aircraft at dusk, but the Navy insisted that it must be free to open fire on any aircraft which closed within 1,500 yards. It may be that the Whitley inadvertently came too close, but the fury of the airmen who were all too frequently shot at by those whom they were endeavouring to protect can easily be understood.

  At 10.15 p.m., on the 4th, when the convoy was at the northern entrance to the Minches, Commander Bockett-Pugh joined up in the Westcott, and took command. The weather was calm and warm, the ships of the convoy had taken up their appointed stations under Commodore Mackenzie’s watchful eye, the escort assumed its screening disposition and course was set N. 74° W. (true). The Westcott being the only escort fitted with radar, Bockett-Pugh spent the night circling his charges. He thus preserved freedom to take station at any time two miles from the convoy in the most probable direction of attack. His orders to his group were that at dusk each evening (about 11 p.m. local time) he himself would sweep ahead, while the Newmarket and Campbeltown did likewise astern and on the quarters, and the Primrose and Nasturtium searched to ten miles on each beam of the convoy. Any shadowing U-boats would thus be forced to submerge, which would add to their difficulty in carrying out a night attack. The searching ships were to be back with the convoy by midnight, and at dawn (about 5 a.m. local time) the whole escort would change from its night anti-submarine disposition to day anti-aircraft stations.1