By Peter Colthorpe
With recent announcements that the redundant naval oil fuel installation beneath the Sydney Domain is to be used in an extension to the Art Gallery of NSW, we asked one of our members with many years of experience as a marine engineer to provide an update on that most important of all commodities fuel oil, without which our ships go nowhere.
Since the inceptionof the RAN, the fleet has needed fuel to power our ships. The first born of our navy, the torpedo boat destroyer HMAS Parramatta and her sister ships were oil burning; the cruisers HMAS Sydney, her sister ships and the battlecruiser HMAS Australia were combined oil and coal burners with the fuel oil being sprayed on the coal to increase its burning rate.
Initially fuel was supplied from Royal Naval or civil sources but in early 1914 the RAN ordered two purpose built support ships. Firstly the oiler Kurumba from the Tyneside yard of Swan Hunter was commissioned in December 1916 but taken into service by the RN, and did not reach Australian waters until July 1919. Interestingly Kurumba herself was coal fired and her boilers were not converted to oil burning until 1929. A second ship, the collier Biloeta,was built by Cockatoo Island Dockyard and commissioned in July 1920; she could also carry 1,250 tons of oil fuel.
Shale oil was exploited in Australia but predominantly this oil was used to distil lighter fuels such as kerosene, Dieseline and petrol. Dieseline could have been used in the oil burning ships but it was normal practice to standardize the fuel with the Royal Navy, hence it is unlikely that the RAN used significant quantities of Australian sourced liquid fuel until the 1960s.
Coal was phased out after the First World War and essentially from 1930s two fuels dominated in the RAN, the heavy oil Navy Special Fuel Oil (NSFO) commonly referred to as Furnace Fuel Oil (FFO) and Diesel Fuel Oil. Diesel fuelled ships were patrol craft, submarines and general purpose vessels. FFO fuelled ships were steam powered ships such as cruisers, destroyers, frigates and corvettes.
Steam powered ships carried about 10% of their fuel as diesel to power the auxiliary generators, ship’s boats and to light off the boilers.
FFO was a black tar-like fuel which needed to be heated to around 220ºF (105ºC) to burn cleanly. Even then it was a dirty fuel in that it created heavy soot deposits in the boiler and uptakes which required the ship to blow soot every four hours and conduct external boiler cleans approximately every six months. The soot build up would often need a saw to cut the debris from between the tubes, a dirty and hard job as the soot was baked into the tube bank.
The tanks were also difficult to clean and the RAN converted the corvette HMAS Colac to a Tank Cleaning Vessel. FFO tanks required long ventilation periods, copious hot water and detergent and a separator system to recover the sludge and grime.Colac could also assist in external boiler cleans by providing hot water delivered in lances to flush the debris built up around the tubes.
Some merchant ship diesels were built to burn FFO or heavy fuel as it is called but up until the 1960s these ships were rarely in naval service. In the 1970s the cost of diesel fuel started to fall and more gas turbine and diesel powered ships were coming on line. The vast array of oilers and fuel depots around the world being managed in the main by Commonwealth navies and the USN needed to cater for more quantities of diesel and so FFO stocks were run down. In the RAN the Type 12 frigates and the DDGs were modified to burn diesel fuel and consequently our FFO stocks also declined. The remaining fuel was disposed of after HMAS Vampire paid off and with her the Tank Cleaning Vessel Colac, because diesel tank cleans are much easier and can be achieved with standard equipment.
Today the fleet is almost entirely fuelled by NATO Fuel F76 Distillate or diesel fuel, with aircraft fuel needs satisfied by F44 AVCAT. The diesels and gas turbines used can burn either fuel but the price difference means that F76 is the fuel most likely found in any RAN vessel, tanker or tank farm. Naval ships can burn commercial diesel fuel but it has a lower storage life so is only used when ships cannot secure F76. One exception is the tanker HMAS Sirius which burns the heavy oil but she will be paid off by 2021 when the two new tankers building in Spain are commissioned.
For the engineer the move to cleaner fuels with less soot and impurities means that combustion side problems are rare. The use of saws and manpower to clean the fireside of boilers and engine exhausts went out with FFO and when the DDGs paid off.
Historically the RAN established its own Oil Fuel Installations (OFI). Initially an oil fuel tank was commissioned at Garden Island in1917 and remains in use for diesel fuel. Prior to the outbreak of WWII three concrete storage tanks were built on the site of the former submarine mining depot at Chowder Bay and these remain in use. The large Domain storage facility also dates from the same period, being installed mainly to satisfy the needs of the British Pacific Fleet. The long disused Domain tanks are now being converted into an extension of the Art Gallery of NSW.
Today, Navy stores her fuel supplies in a combination of OFIs such as Chowder Bay, the oil tank on the hill at Garden Island and OFIs at Darwin, Stirling and Cairns. The two tankers HMA Ships Success and Sirius carry a significant amount but the fleet also relies on commercial tank farms to hold fuel in other ports. Fuel lighters provide alongside fuelling services but only carry enough fuel to service a few ships at a time.
Will there be a change in the future? Unlikely unless the nuclear option is explored, but liquid fuels, in particular F76, are likely to remain the staple fuel for some time to come.