The various design and technological developments that allowed the creation of fast Coastal Forces boats was not something that happened overnight. In fact, the important elements of their design can be traced back to the second half of the 19th century.
This was a period of massive change in marine technology and the Royal Navy was undergoing a series of rapid, spasmodic evolutions as they sought to keep pace with new weapons, machinery and tactics. As sail gave way to steam, there were three important developments that would lead to the MTBs and MGBs of the future.
In 1866, in his factory in Fiume, Austria-Hungary (now part of Croatia), Englishman Robert Whitehead perfected the design of the self-guided torpedo. This revolutionary weapon would change naval warfare completely, although its impact would not be fully felt for some decades yet.1
Six years later, in 1872, Charles Meade Ramus, Rector of Playden and East Guldeford (near Rye, Sussex) had his design for a ‘polysphenic’ ship patented. He also contacted the Admiralty, informing them of the results of his own experiments and suggesting a new future in warship hull design.2
Ramus’ idea was to create a stepped hull. Essentially, his design divided two sections of angled flat hull boat bottom (or flat planes) with a step approximately halfway down the hull’s length. In theory this would lift the hull up and out of the water as its speed increased, decreasing water resistance and allowing higher speeds to be attained. The step would further decrease surface contact, allowing the hull to skim.2
The Admiralty were unimpressed, but conducted a series of tests nonetheless. These suggested that Ramus’ hull was, if anything, even less effective than a traditional round, displacement hull. But Ramus’ hull was revolutionary. The test’s failures were because Ramus’ design was meant for a 350ft long hull, where the flat bottom still maintained significant surface contact with the water, reducing speed. Additionally, although the bottom of the hull was effective, the stern of his boat was too curved, which drew water up around it and caused it to drag more in the water. Only five years later, John Isaac Thornycroft patented an evolved version of the design, reducing the vessel size, flattening the stern and introducing a gap in the hull’s side that drew air into the step below the hull, further increasing lift.3
In simpler terms, what these men had created, and what Thornycroft would go on to evolve considerably in wartime, was a ‘planing’ (or hydroplane) hull. Unlike a conventional ship’s hull that displaced water and drove through it under power, a planning hull would lift out of the water as its speed increased, eventually riding almost on top of it, or skimming, much like a flat stone on a smooth pond. Both Ramus and Thornycroft had used a stepped hull design that encouraged the lift of the boat, although other methods of planing would evolve.4
But there was one more hurdle to overcome — propulsion. Ramus and Thornycraft had built little more than model rafts to test their designs, towed by much large vessels with sufficient steam or sail to move the rafts at speed. Installing steam engines and sufficient quantities of coal to power them would add weight and nullify the hull design. There remained only one part of the puzzle and this too came in the 19th century. In the same decade as Ramus and Thornycroft patented their ideas, men like Gottlieb Daimler and Karl Benz were producing some of the world’s first true internal combustion engines. These paved the way for the first automobiles, although they were not quite ready for boats.
The very first torpedo boats were therefore traditional round hull vessels with a coal powered steam engines. Gitana, an experimental spar-torpedo boat launched in 1873, was followed by HMS Lightning, perhaps the first true self-guided torpedo boat. Built by Thornycroft in 1876, it was later renamed Torpedo Boat No. 1 and armed with a solitary torpedo tube in the bow, from which a torpedo could be launched simply by pushing it from behind. TB 1 was the first of many evolutions of torpedo carrying craft. Each design enlarged on the next and in response the world’s navies began to build vessels to counter this new threat — first ‘torpedo gunboats’ and then ‘torpedo boat destroyers’. These ships too evolved and soon, with their increased size, speed and ability to carry torpedoes of their own, the torpedo boat destroyers replaced the smaller torpedo boats. By the early 20th century, they came to be known simply as destroyers.5 The future vessels of Coastal Forces would not evolve from these early torpedo boats.
But even whilst Lightning was steaming around Britain, designers were starting to marry combustion engines with boats. In 1886, Daimler and his colleague Wilhelm Maybach successfully placed an early petrol automobile engines into a boat. Two years later, the Priestman Brothers (William and Samuel) created the first purpose designed motor boat, operating with a kerosene fuelled engine. In 1891, J. D. Roots fitted an genuine internal combustion engine into a boat and operated a ferry service on the Thames.6
Sport provided an incentive to increase speed and efficiency.4 Since the 1870s, the flat bottomed hull recommended by Ramus had evolved and engineers experimented with the planes at both the bow and the stern. It was discovered that a flat bottom was less efficient that a V-shaped hull. Gradually it was discovered that a flatter V (in cross section) was needed towards the stern of the boat in order to encourage planing. The hydroplane hull therefore needed flowing lines where the sides of the ship’s bow merged into the shallow V-shaped planes of the bottom of the hull. This design in turn called for a sharp angle between the sides of the hull and the underside of the hull towards the stern. This corner is called the chine and the design therefore became known as a ‘hard chine’. In a series of designs starting in 1909, American William Henry Fauber began to integrate a hard chine and stepped hull with a normal ship’s bow, creating the modern hydroplane.7
Thornycroft himself had played a significant role in the creation of destroyers and he later began to pioneer the use of fuel oil in the Royal Navy, work for which he was knighted in 1902. But, despite this progression into larger ships, he had not forgotten the planing hull. He developed a series of boats that he described as ‘skimmers’, in particular the Miranda series. In the 1908 London Olympics, the only Olympics to ever feature powerboat racing, he entered a boat skippered by his son, Isaac Thomas. At the three events held on Southampton Water that August, the Gyrinus II, with its planing hull, won two of the three gold medals available.8 Two years later, the Miranda series reached its peak with the launch of Miranda IV.
- Edwyn Gray, 1991. The Devil’s Device: Robert Whitehead and the History of the Torpedo. Naval Institute Press.
- Anon, 1914. Flight, July 24. p.796
- William Henry Fauber, 1912. Advantages of the Multiplane. Motor Boating, January 1912. p.50
- Christopher Dawson, 1972. A Quest for Speed at Sea. Vosper Ltd.
- Robert Gardiner (editor), 1979. Conway’s All the World’s Fighting Ships, 1860–1905. Conway Maritime Press.
- Bernard B. Redwood, 1906. Motor Boats. Journal of the Society of Arts, 23 March. p.512
- W. H. Fauber, 1912. Ibid. pp.3-5
- Theodore Andrea Cook, 1908. The Fourth Olympiad, Being the Official Report. British Olympic Association. p.227
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