As Curator of Ship Models, I need to ensure that the Museum collects examples of vessels of historical and technical importance to expand our world-class collection of over 3000 models. As well as historical models we are always looking for examples which keep pace with current developments in shipping.
L0448-001.jpgLNG Carrier Methane Heather Sally (ZBA4653)
One of our most recent acquisitions is the Liquid Natural Gas Carrier (LNG) Methane Heather Sally, kindly presented to the museum by the BG Group in 2009. As the UK's natural gas reserves are diminishing, the gas supply companies have to import gas from abroad. Carrying this commodity in bulk - economically and by sea - is certainly challenging as the gas has to be refrigerated at a temperature of minus 161 degrees centigrade. The NMM's ship model collection already includes examples of the earliest ships to transport this cargo, dating from the 1970s onwards, and this fine, full-hulled example brings the story right up to date. It is slightly unusual in that the hull includes a cut-away section showing the internal layout and construction of the gas cells.
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As you can see, the port side towards the bow shows the various colour-coded layers of the membrane containment system which comprises stainless steel, glass-fibre cloth and an aluminum foam wood sandwich. The volume of gas carried by the vessel, once expanded from its liquid form, is 145,000 cubic metres, which is enough to power over half a million American homes for a month!
This vessel is also typical of modern shipbuilding, with most vessels designed with the greenest credentials and the ability to re-cycle the hull materials at the end of their working life. Some of the more notable green features on the Methane Heather Sally include:-

  • Using the boil-off gas to fuel the boilers for both the main engines and electrical generators, rather than using additional energy for refrigerating the LNG
  • Burning gas rather than heavy fuel oil, which reduces CO2, NO2 and SO2 emissions
  • A waste oil incinerator and rubbish re-cycling and compactor
  • A safe water ballast transfer system which prevents the movement of invasive marine species to undesired locations

These ships are theoretically able to circumnavigate the world around the zero meridians in about 44 days at an operating speed of 20 knots. They will be operating in and out of a new handling facility currently under construction at Milford Haven.