On the development of UNREP
Puddefoot, Geoff. Ready For Anything : The Royal Fleet Auxiliary 1905-1950. Seaforth Publishing. Kindle Edition.
By 1908, clearly influenced by what they must have seen as future needs, Admiralty planners had introduced the first RFA tanker construction programme, ostensibly after a recommendation by the then Director of Stores, Sir John Forsey. It is not generally known that Forsey’s reasons for introducing Burma had nothing to do with an innovative approach to replenishment at sea. Rather, the reasons were economic.
He had originally planned to have Chatham Dockyard build four 500-ton barges to use for transporting oil to ports around the coast. By 1908, the position had changed sufficiently for him to decide to abandon that idea in favour of one ship of between 1000 and 2000 tons. What he wanted was a simple oil tanker. It was not until the Admiralty got their hands on the plans that the idea of making her RAS-capable occurred to anyone. And, all of this was happening, once again, while Sir John Fisher was First Sea Lord. In fact, all of the purpose-designed, RAS-capable classes appeared, at least in design terms, during his tenure at the Admiralty.
Burma, launched in 1911, was the initial result of the 1908 programme. Of only 2000-tons capacity, fairly small by present day standards (Wave Knight, for example, can carry about 5000 tonnes of DIESO, 3000 tonnes of aviation fuel, and water besides), she was equipped for refuelling at sea by the stirrup method and fuelling alongside (also known as ‘rafting up’), that is, replenishing vessels in harbour or a sheltered anchorage. Significantly perhaps, given the difficulties inherent in the stirrup method, the RAS capacity of this class does not seem to have been extensively used.
Oiling-at-sea experiments, however, using bronze hoses, had begun sometime before both Petroleum’s and Burma’s appearance, in 1905, with the 1893-built tanker Henri Rieth. The only reference found, so far, to these trials is a mention in the report by C-in-C Atlantic Fleet, dated 31 March 1906, in which he refers to ‘300 ft of metallic hose which was originally purchased for trial in the SS “Henri Rieth” in connection with the supply of oil fuel to HM Ships when underway at sea …’
No mention is made as to whether these trials were carried out and the first detailed report of the results of oiling-at-sea trials are those between Petroleum and the battleship HMS Victorious, submitted by the C-in-C Atlantic Fleet in the same report, dated 31 March 1906.
Petroleum was not only the Admiralty’s first tanker, but also she appears to have been the first RFA with purpose-built modifications to enable her to oil a Royal Navy ship at sea.
She began trials of this technique late in March 1906, with a practice pump-over to HMS Victorious. Curiously, these trials were carried out with water not fuel oil, because Victorious was a coal burner. Presumably, the Admiralty used her to assess the sort of problems that might develop when oiling large warships. Destroyers were, for the most part, oil fuelled by this time and criteria and equipment requirements for oiling destroyers at sea were also claimed to have been agreed in a coaling-at-sea conference at the Admiralty on 5 December 1906.
A report on the Petroleum/ Victorious trials records that these were carried out while Petroleum was being towed, using 6.5-inch (16.5-cm) wire hawser, with the vessels 90 fathoms (180 metres) apart.
Twenty-seven lengths of hose, each 20 feet long, were required to span the distance between the ships. These were coupled up beforehand, attached or ‘seized’ on to a 3-inch wire jackstay, with a 5.5-inch wire used as a travelling jackstay for the hose. Rope ‘pendants’ attached to roller shackles were used to secure the hose to this 5.5-inch wire and the hose was hauled along the wire by a separate 3.5-inch wire from the towing ship, the roller shackles being secured to the 5.5-inch wire as the hose was paid out. Clearly, this was an early form of the justly maligned ‘stirrup’ method and using it, the two ships managed to transfer 115 tons of water per hour.
The report concludes that this arrangement for oiling-at-sea should be satisfactory, at speeds of up to 12 knots, in fine weather at sea. This conclusion was reached despite the fact that passing the hoses, on their stirrup rig, between Victorious and Petroleum took 5 hours, although this did include a 1-hour break for meals, with a further 3 hours to recover the hoses back to the RFA! (By way of comparison, the crew of a modern RFA, such as Wave Knight, would usually expect to take about 15 minutes to get ready for a pump-over, and about 2– 5 minutes after that to connect to the receiving ship. Similar time is needed to disconnect.)
Both steel and bronze hoses were used during these trials aboard Petroleum (although, her master actually refers to the latter as ‘copper’) and it was finally concluded that ‘bronze’ was best, although it appeared to be more affected by fuel oil than the steel type.
Despite the disadvantages of her equipment and stability problems, RFA Burma was also involved in some unsuccessful oiling-at-sea trials in 1911. Arrangements were similar to those of Petroleum, except that it had been decided that, when oiling a destroyer, Burma should do the towing, with positions reversed when refuelling a larger vessel, such as a battleship.
Trials began well. Test pumping carried out while she was tied up in Greenock dockyard showed she could pump a respectable 350 tons of water/ hour through her pair of 5-inch (13-cm) hoses, which were 160 metres long. That was, of course, unless the high pumping pressure did not burst them, which it frequently did. And when she went to sea, as might be expected, the stirrup method proved, at best, clumsy and at worst, extremely dangerous, especially with any sort of sea running.
This was hardly surprising, given this description, and implied criticism, of the procedure used for securing the stirrups when hauling the hose outboard:
It was found that when the hose was being hauled outboard, hardly time enough was allowed to detach the stirrup from the rail, pass it under the bracket, hook it on the towing wire and set the spring before it passed over the stern, and consequently several were not hooked on, making an increased length of unsupported hose. This is most inadvisable. In the reverse operation when hauling in the hose after oiling had been finished, difficulty was again experienced in getting the stirrups off in time, and consequently the hauling in had to be stopped occasionally.
A man was subsequently placed outboard to detach the stirrups, and hauling in proceeded without a stop, but this is a dangerous proceeding and should not be allowed.
No wonder the old time RFA men advised anyone using this method to ‘keep a bucket handy to collect all the spare thumbs’!
In the light of the thirty or so years that elapsed between Petroleum’s purchase, the later Burma experiments in 1911 and the Royal Navy’s eventual development of a reliable fuelling at sea rig during 1941– 3, it may be of interest to note some comments made at the time of Petroleum’s purchase, in 1905 (Sigwart, 1969): …
she will be used to follow the Atlantic Fleet, and the pumping arrangements are so designed that she can be towed behind a battleship and a flexible hose passed from the forecastle to the battleship through which fuel can be pumped in any ordinary weather at sea. (author’s emphasis) When in harbour, connections have been arranged so that oil can be pumped through the side when the vessel is lying alongside one of HM ships. In case of need, oil can also be pumped over the stern … …
The purchase of SS Petroleum shows that the Navy have determined extensively to adopt fuel oil.
Clearly, this further confirms that the ship was bought with the sole end in view of developing reliable technology for refuelling at sea. Many in the Royal Navy were in favour of the idea, so why:
(1) Did the navy settle for ‘rafting up’ as its main refuelling procedure, without apparently making further, more serious attempts to develop reliable RAS technology? Cost might have been an issue but it cannot have been the whole story.
(2) Apparently ignore RAS developments in other countries, particularly the United States, with which scientific and technical relations were harmonious and which had been using rubber hoses hung, on a single wooden saddle or trough, for fuel replenishment since 1917?
(3) Specifically, ignore the development of synthetic rubber hose technology, which was to revolutionise replenishment-at-sea and which the Navy had in place barely 12 months after the capture of the German auxiliary Lothringen in 1940? Or were they ignoring it?
Although extensive oiling-at-sea trials were still being carried out by the British, fuelling alongside continued to be the predominant technique in use by the Royal Navy until the beginning of the Second World War, despite the fact that the United States, Japan and most significantly, the German Navy, had quickly seen the advantages inherent in oiling-at-sea. This was to have considerable repercussions during the early stages of the Atlantic war, when, in 1939– 40, the inability to refuel warships, particularly convoy escorts, had dire consequences.
Although it is not generally acknowledged either, the stirrup method was not the only method under consideration by the Admiralty during this period.
In December 1913, a Captain Fairfield approached the Admiralty with a revolutionary idea for oiling-at-sea, using a steel bound, leather hose, 130 fathoms (about 250 metres) long, which he claimed could be used in one piece. The towing hawser itself consisted of a number of flexible steel, wire ropes, running parallel with and attached to the hose, and ‘of sufficient strength to take the whole of the towing forces’.
More wire ropes were bound around the hose to secure the towing wires and prevent the hose from bursting. The hose was to be secured to both the receiving and delivering ships by attaching the towing lines to sleeve pieces with strong collars on the inboard end which would, in turn, be attached to pedestals mounted on turntables. This would, the inventor felt, give sufficient freedom of movement to keep the collars and hoses in a straight line when the vessel yawed.
The Admiralty had several serious objections to Fairfield’s invention, in that they could neither see how the hose was to be cleared of oil, nor how it was to be repaired or stored. Interestingly, the inventor’s suggestion was that compressed air was used to clear the hose, while it could be stored on a large drum similar to that used aboard cable ships. As anyone who has served with the RFA will know quite well, compressed air is universally used to clear hoses and the newest astern liquid replenishment technology is a device called the Hudson reel, which consists of a rubber hose, on a large reel, which is streamed astern to the receiving ship, although admittedly ships nowadays are not towed but maintain position by station keeping, thus doing away with the need for Fairfield’s admittedly over-complex towing arrangements.
Repairing Fairfield’s device also was not so straightforward. The inventor suggested that the outer sheathing and wire reinforcement be cut, whereupon the hose could be repaired and the sheathing reinstated. What an interesting exercise that might have been, at night, with any sort of sea running.
Of course, nothing ever came of Fairfield’s invention, the inventor being kindly informed that:
… the Admiralty felt the matter to be of considerable importance, and would welcome any practical proposals for facilitating oiling ships at sea and hoped that, after hearing this and discussing the matter with his friends, he would be able to write to the Admiralty in such a way as to permit steps being taken to test the value of the proposal.
Just what the Admiralty considered the necessary ‘steps’ to be, had been made very clear to the unfortunate captain early in the meeting when the minutes recorded: ‘The possibility of making a definite trial, free of expense to the Admiralty, was discussed, but the inventor was not able to say that he could make a definite proposal.’
Perhaps Fairfield should have tried his luck with the Americans … or the Germans.
By 1912, in one final, important, pre-war development, initial installations of Marconi wireless telegraphy (W/ T) had begun to be made into RFA ships, along with generators that were intended both to run these sets and the proposed electric lighting systems, which were also to be installed in the selected vessels. Operators during this period were usually civilian telegraphists, employed by the Marconi Company.
Technological innovation in the early RFA had begun well but for reasons which are not quite clear, this early impetus was not maintained.
Abandonment of the fuelling at sea trials does appear to have coincided with Sir John Fisher’s replacement as First Sea Lord. He may well have been the impetus behind this early drive to solve the problem of replenishment at sea and, with his influence gone, and less far-sighted individuals taking his place, further efforts were abandoned.
It can only be speculation but it seems at least reasonable to ask, given the distinction that was made between RFAs and MFAs, along with the extensive RAS modification of Petroleum before purchase, in what direction the new RFA fleet might have been taken?
Did Sir John intend to have a purpose-built, navy-manned replenishment fleet, of which Petroleum was the first member?
Did he then further intend that this should be separate from the freighting service, which would then make use of the Admiralty’s MFAs?
And so should we be writing here … Sir John Fisher, founder of the Royal Fleet Auxiliary service?
Whatever the reasons behind it, no Royal Navy ship would routinely refuel at sea until the Second World War and then the technology used would be largely developments of German or US equipment, despite the fact that many of the early replenishment trials had been conducted by the British.
Fortunately, this lack of a replenishment-at-sea capacity was not to prove too great a disadvantage during the First World War, because the Royal Navy, with the exception of the Battle of Coronel, was only to engage in major fleet actions against the Germans in the North Sea, where refuelling (or recoaling) could take place at one of the large UK bases. Despite still being predominantly an oil transport and freighting service after 1918, the First World War was also to bring in its wake an unprecedented expansion of both the RFA fleet and its role within the UK armed forces.
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Appendix 5
Refuelling at Sea 1905– 50
During the 1920s and the 1930s, the RFA’s predominant task logistically had consisted of transporting fuel and dry stores to Royal Navy shore bases. Replenishment-at-sea (RAS) was still an unreliable, slow and largely experimental technique.
Prior to 1936 and the Supply Ships Committee, financial constraints and short sighted thinking had forced the Admiralty to shelve any programme that might have allowed the development of an efficient rig for refuelling at sea. In a meeting at the Admiralty, as late as 1938: ‘Their Lordships decided that, generally speaking, the larger ships (author’s note: ie, bigger than destroyers), would not require to oil underway.’
It was further considered that battleships and most other warships would always be able to refuel in harbour or at ‘an exposed anchorage’.
Few RFA tankers were even equipped for refuelling-at-sea, the predominant prewar method of refuelling warships involving the tanker being alongside the receiving vessel in a sheltered anchorage. Incidentally, many of the world’s navies still use this method as their preferred technique, only the Royal Navy, the US Navy and a couple of European services having developed sophisticated RAS techniques. This is a field in which British superiority has become a marked feature, so much so that many foreign navies send their ships to Portland for training in RAS techniques with RFA vessels.
Wartime pressures and the loss of bases like Singapore accelerated technological development in RAS techniques, as in many other fields, and by 1945, with the help of captured German equipment, oiling-at-sea was becoming almost routine, while significant progress had been made on techniques for jackstay transfer of both dry stores and ammunition.
Petroleum was the first RFA tanker to be modified for refuelling-at-sea (RAS). Bought from her builders in 1906, the purchase price included 600 feet of Admiralty hose and several modifications to her pumping arrangements. This included a 5-inch deck connector which could be used to draw excess oil out of the hose, after refuelling was finished. She was fitted for refuelling by the stirrup method, which was to be the predominant technique until the early 1930s. Burma, accepted into the RFA fleet in 1911, was similarly equipped.
The First World War was dissimilar in many respect to the later conflict and no more so than in the nature of naval logistic operations. Most engagements took place in the North Sea or Atlantic, well within reach of port refuelling facilities. So there was no pressure on the Royal Navy to perfect RAS techniques, unlike their counterparts in the US Navy. Importantly, RAS development was not helped by the many warships on both sides being coal burners.
One of the first serious British attempts at improving fuel replenishment, after the First World War, was conducted in 1924, using what was called the ‘hose hawser’ method.
This technique employed a hawser, by which the receiving ship was towed, passed through the fuel hose. It proved extremely unreliable and the service soon reverted to the stirrup method, whereby a 3.5-inch metal hose was suspended from the towing hawser by a series of brass stirrups mounted on rollers, the practice now being for the tanker to tow the receiving ship.
The system was dangerous and time-consuming, since each stirrup on the fuelling hose had to be transferred from the stirrup rail to the towing hawser by a crew member. The whole complex arrangement was then passed out of a special stern chute and along the hawser to the receiving ship. Adding to the difficulty was the need to secure a cork lifebelt around the hose, halfway between each stirrup, to keep it afloat in the event of a breakage, an all too common occurrence with this particular rig. Having secured the hose, pumping could begin, and rates of about 120 tons per hour usually were achieved. The high pressures needed to achieve even this rate in the long and tortuously coiled metal hose resulted in frequent bursts, which delayed fuel transfer even more.
Needless to say, the RFA men who were called upon to operate it were not very keen on the system, either, their usual advice to newcomers being ‘… keep a bucket handy for spare thumbs’, because of the danger inherent in transferring the stirrups while the hose was moving down the stern chute.
Despite its fairly obvious shortcomings, the stirrup method remained in service until the Second World War, although, by 1937, trials had begun with the ‘trough’ system.
This technique involved the tanker and the receiving ship steaming abeam of each other, some 70 yards apart, secured by a towing hawser and a breast rope.
While maintaining the required distance by station keeping and adjustment of the breast rope, the tanker lowered a derrick from which was suspended a single trough containing two 5-inch flexible bronze hoses, through which fuel oil could be pumped at rates of about 500 tons per hour. Burst hoses were still a problem, however, until the next major breakthrough.
This came in 1941, when two German support tankers, Lothringren and Gedania, were captured and found to be using buoyant rubber hoses for refuelling. British trials quickly resulted in the production of a successful 5-inch buoyant rubber hose, which could be filled with compressed air and simply hauled across to the receiving ship, vastly simplifying the stern replenishment process. Stirrup rails and stern chutes were now dispensed with, the hose being simply laid out on a set of wooden or cast iron rollers, before being attached to a wire rope and then passed through a roller fair lead, usually 5 inch, situated in the stern of the vessel. The wire rope was transferred to the warship by means of a thin ‘messenger’, which was either attached to a float, to be grappled by the warship, or fired across by a service rifle fitted with a special adapter. This messenger was then hauled across with the wire rope attached (or ‘seized on’), followed in turn by the inflated rubber fuelling hose.
Since it was both simple to install and effective in operation, this was the preferred method for both RFAs and the escort oilers which accompanied many Second World War convoys, especially as it cut down replenishment times considerably. Connecting up, in particular, was considerably simplified. HMCS Athabaskan set a record for this operation, during the Korean War, when she managed it, from line hitting the deck to coupled fuel hoses, in one minute forty seconds. Not bad when one considers that during the RFA’s first refuelling trials with bronze hose, between Petroleum and HMS Victorious, connecting up took five hours, including a break for meals! Admittedly, disconnecting was quicker. It only took three hours!
Rubber now replaced the bronze and canvas hoses previously in use for the trough method as well. Together with the fitting of experimental gantry-type ‘King’ posts and long net-defence derricks to Broomdale, this began the development of the sophisticated RAS equipment in use by today’s RFAs.
Advances were not just being made in liquid replenishment (RAS( L)), however. Warships needed victualling stores and ammunition as well, which also had to be provided at sea.
During the Pacific war, the US Navy developed sound techniques for jack-stay transfer of ammunition and dry stores and the Royal Navy were not slow to follow their lead, having previously used an unsatisfactory ‘whip and inhaul’ method for stores transfer. Modern jackstay techniques grew out of these early beginnings, with loads of up to five tons now being routinely transferred between ships. The development of what is termed ‘vertical replenishment’ (VERTREP) by helicopters has, of course, added a whole new dimension to the RFA’s ability to replenish warships at seas.
Who knows what new techniques will appear during the twenty-first century? Whatever they are, the RFA is sure to be, as usual, in the forefront of any developments which make their job of replenishing the Royal Navy’s warships more efficient.
