The subject of shipping protection has a direct relevance to us as the country, being wholly dependent on seaborne trade, is constrained to ensure its protection at times. In fact, one of the Navy’s primary tasks is to ensure the safety of our sea lines of communications.
A glance at our area of interest, the Indian Ocean region, shows that our three main trade routes are via the Red Sea, through the Malacca Straits and from the adjoining Gulf. It is obvious that physical defence of our shipping emanating from all these routes may be problematic, to say the least. Reliance would have to be placed on suitable merchantmen carrying our cargo, following international shipping routes up to the Gulf. Onward transshipment to Pakistani ports can then be organised from there, with our protective thrust based on this coastal route.
The only way Guerre de Course has been successfully countered in the past has been by the application of the convoy system ie the direct escort of groups of merchantmen by warships. In addition, certain support forces were also used in tandem. The convoy system proved effective in maintaining the flow of shipping as it combined the advantages of both the offensive and defensive forms of war as analysed by Clausewitz and Corbett. It has thus historically been the best method of optimising the effect of relatively few naval assets.
In the great maritime wars of the period 1660 to 1815, the convoy system was almost taken as a norm. A closer look at the relevant aspects of the two world wars would serve as a better guide in view of the emergence of the submarine threat.
When the German Navy stepped up its U-boat campaign in 1916, the average tonnage sunk monthly from October to December of that year had been over 300,000. The prevailing state of affairs had led Jellico, the Commander of the Grand Fleet, to warn that if such wastage continued, Great Britain might soon be compelled to sue for peace. The Admiralty hierarchy, despite being helpless in the face of this onslaught, still kept strongly opposing the convoy system on supposedly technical grounds. Prime Minister Lloyd George, on the other hand, was keenly inclined towards such experimentation and his views were further buttressed by his private discussions with junior officers. As the Premier put it, “whenever I urged the adoption of the convoy system, I was met with the blank wall of assertion that the experts of the Admiralty knew on technical grounds that it was impossible. That is a very difficult argument to counter.”
Immediately after America entered the war, though, the Admiralty, on 26 April 1917, set aside 18 destroyers as escorts. The institution of the convoy system immediately proved successful. The destruction to tonnage in the last quarter of 1917 was half that of the period April to June and maintained a steady decline curve throughout 1918. No submarine ever succeeded in bagging a large proportion of any convoy. By the time of the Armistice, more than 88,000 vessels had been convoyed with a loss of only 436, with the comparative U-boat losses being 180, half of the available boats.
In the Mediterranean theatre, the local commander was likewise unwilling to introduce the convoy system, preferring instead an increased and unceasing offensive, with the hope that this would in time enable him to dispense with the convoy system and suchlike methods of defence. His preferred measures, which included offensive patrols, mine laying, bombing of U-boat bases, not only failed to stop the German and Austrian submarines getting into the Mediterranean, they barely managed to sink a single U-boat. The limited escort allowed to each convoy, usually a sloop and two trawlers for thirty ships, sank by contrast eight out of twelve U-boats lost in the arena in 1917-1918, while keeping the loss rate of Allied ships in the convoy at one percent.
During World War 2, a partial convoy system was introduced in 1939 but given the diversion of assets to other priorities, it was far from effective. This allowed the Germans with their limited number of submarines to inflict almost all their losses on Allied merchant shipping. Up to the fall of France, U-boats had sunk some 200 British, Allied and neutral merchant ships sailing independently. Of the many thousands of ships that sailed in French and British convoys, only fifteen were sunk, while eight of the attacking U-boats were lost at the hands of the escorts – an intolerable exchange rate for the U-boats.
When the U-boats were unleashed against coastal shipping off the American eastern seaboard, around 500 ships were sunk in the first six months of 1942. With the institution of the convoy system in July 1942, the losses went down to barely 0.3 percent.
In the Pacific, the success of the American Guerre de Course against the Japanese was in large part due to the latter’s failure to come up with a proper convoy system.
Analysis of the Lessons of History
Why was the convoy so successful in the two world wars? Simply because it presented a confusing target to a submarine which had to visually get it in its sights. How so? Because of the large number of elaborately camouflaged ships in the convoy, all of them carrying out evasive steering in formation. These concentrations moreover proved much more difficult to find than single ships, for the same number of individual units dispersed over separate routes would have been visible over a much larger sea space. In theory, the convoy should have been a bigger and more convenient target; in practise it was the opposite. The convoy hence offered the individual merchantman the greatest mathematical chance of escaping detection and attack altogether, even if it was totally unescorted. Convoy also offered the best chance of finding, destroying and neutralising commerce raiders. The escorts moreover kept the submarines at a distance and forced them to discharge their torpedoes at long range without much accuracy.
Coming to the present and taking stock of our peculiar situation, one finds that Pakistan too is highly vulnerable to an anti-shipping threat. Keeping in view the lessons of history as outlined, the general belief inclines towards convoy escorting as the only solution. But is it?
Before deliberating further on this issue, it may be useful to view the differences in scenario between the Atlantic Ocean of the early nineteen forties and Arabian Sea of today:
a. The German U-boats were then the major threat to shipping. These boats had to remain on the surface for prolonged periods for reconnaissance and chasing after the submarines for engaging targets. In comparison, present day submarines, particularly nuclear ones or those equipped with Air Independent Propulsion, can stay submerged for long periods. They can also detect and engage targets at long ranges and do high speeds submerged. While the U-boats had to return harbour after almost every successful atack for reloads, present day conventional submarines can carry around 24 torpedoes/missiles.
b. The Atlantic crossing was a wide expanse as compared to coastal waters in our area of interest. The battle in the Atlantic was on a gigantic scale, with as many as 300 ships forming a convoy and nearly 20 to 30 submarines converging at times in Wolfpack tactics.
c. Because of non-availability of suitable aircraft in the German Navy, the threat posed to convoys was primarily from the U-boats. In our waters, aircraft armed with anti-surface missiles constitute an equally potent threat, possibly more so.
d. Once the U-boats position had been revealed to the escorts, it became very difficult to evade a counter attack. Present day submarines can exercise greater discretion by attacking from stand-off ranges and have better chances of evasion.
e. Though the U-boats notched up some spectacular successes, the Allies managed to stay ahead by virtue of their capacity to adequately cover up their shipping losses through new constructions. America’s entry into the two world wars bolstered both the shipping tonnage as well as the escorts. In our case, replacement of losses in a short span of time would be problematic.
f. Lastly and most important, a convoy in that scenario and in those days had better chances of evading detection and cutting losses as compared to individual ships. The situation is quite different today with availability of satellite pictures and information relayed by the Maritime Patrol Aircraft.
Coming to the million dollar question as to whether the convoy escorting system still provides the only answer to our problems or its time to have a relook at the other possibilities available, it is felt that the traditional method of convoys and escorts may not prove viable in our case owing to the following:
a. A large convoy traversing our coast would be highly vulnerable to sequential submarine and ASV attacks and more specifically to a coordinated subsurface and air attack.
b. Number of escorting units likely to be available is limited. With no hope of replacements, these escorts would not last long if employed regularly with the convoy, in the face of a credible torpedo and missile threat throughout each passage.
Supposing the convoy system is resorted to, let us speculate on the optimum size of a convoy in our scenario. Considering a passage of 36 hours one way from a Marshalling Point in the Gulf of Oman to a Pakistani port, turn around time included, the earliest the next incoming convoy can be escorted in would be three days. One one can thus imagine the bulkiness of each convoy, keeping our expected daily import requirements in mind, then visualise how long the escorts in particular of such a large convoy will last in the face of a determined three dimensional onslaught.
The object of this paper is to generate out of the box thinking. The bottom line is that whatever strategy and tactics are adopted to ensure the safety of our sea lines of communications, the fact remains that placing our trust solely on the convoy system may not yield the desired dividends.