Total Undersea War

Aaron Hamilton’s book sets out to counter the popular argument that the Battle of the Atlantic was effectively won by the Allies in 1943, in ‘Black May’ as it became known. The introduction of the snorkel (anglicised version of the German name ‘schnorkel’) and its attendant devices including anti-radar coating and acoustic camouflage, were highly significant developments which, by the end of the war, threatened to tip the balance back in favour of the U-Boat. Just as importantly, they paved the way for what were effectively submersibles, with their requirement to surface regularly to replenish their oxygen supplies, to become true submarines. What is remarkable is that the innovation and deployment of this ‘air mast’, which allowed the snorkel-equipped boats to remain submerged for increasingly long periods of time, was accomplished in the middle of a world war. ‘Salvation’ as the author describes it, came in the form of a letter from a private U-Boat engineer Dr Hellmuth Walter, sent to Admiral Dönitz during that fateful May, which was to become the catalyst for the rapid experimentation and then deployment of the snorkel. As a consequence, the last year of the war saw a radical change in tactics from mass ‘Wolfpack’ attacking formations in the central North Atlantic to single U-Boats seeking their victims in coastal waters, particularly around convoy ‘choke points’. Additionally, the increasing confidence shown in the snorkel device enabled the boats to stay submerged for between fifty to seventy days, records which were not surpassed until the introduction of the nuclear submarine. Thus the snorkel enabled the U-Boat, for instance, to avoid detection while crossing what had become the Bay of Biscay ‘killing-ground’ before disappearing into the wastes of the Atlantic. Hamilton explains the working of the device in extensive technical detail in the first part of the book aided by a number of excellent close-up, contemporary photographs. Similar attention is given to the rubber coating applied to the snorkel head and mast. Owing to the increasing ability of the Allies’ surface search airborne radar sets, what might otherwise have been the ‘achilles heel’ of the snorkel was effectively countered. Of equal, if not greater significance in terms of the post-war evolution in submarine technology, was the use of rubber coating to reduce sound wave emissions which the author calls ‘one of the least understood of wartime technical developments’. In the decade before Black May, the German BdU had identified ASDIC as the most potent threat to its boats and the discovery of an effective countermeasure was handed the highest priority. Thus, the anechoic tiles, which are used on the hulls of contemporary submarines, trace their lineage directly to the ground-breaking ‘Alberich’ tiles. Make no mistake, this is an important book which dispels many of the false assumptions often made in the vast ‘library’ of books about who won the U-Boat war. Instead, the author rightly concentrates on the undoubted significance of the snorkel and accompanying devices as part of an evolutionary process in the historical development of the submarine.