Feature 2 |MARINE COMPOSITES & CONSTRUCTION MATERIALS
Figure 3. Manufacture at Green Marine of Flax/Greenpoxy, cork cored, RS800 double handed skiff
off-the-shelf green resins also come with manufacturing difficulties which can range from short gel times, high exotherms or high viscosity.
The
challenge will be to keep manufacturing methods with natural composites as familiar to current boatbuilding practice as conventional composite systems.
New projects To try and address the concerns of the industry in becoming more familiar with these materials, in terms of structural design and production, the University of Southampton has initiated two projects. Firstly, a longer term project to look at production difficulties and long term ageing. Tommi Buckley, Project Manager at Composite Mouldings Group, says: “With diminishing fossil fuel reserves and an established renewable energy market there is no sooner time to establish these materials for mainstream manufacturing,” and, with their expertise in production, three Foxer dinghies (courtesy of REIDmarine) are being manufactured: a vacuum infused flax/ epoxy boat, a glass woven roving/linseed oil epoxy (cured using UV light), and a standard hand layup glass chopped strand mat/polyester construction for comparison. Tese will have fibre optic strain gauges cast into the lay-up to monitor stress build up in construction and importantly to monitor stress through life as they float side by side in a lake. Weight gain will be periodically
48
checked and local panel stiffness changes mapped against weather conditions. Secondly, eight final year Ship
Science students at the University were tasked to design the structure, matching structural performance with the current conventional glass/epoxy construction, build a high performance RS800 skiff from natural composites to prove manufacturing effectiveness, and measure the environmental impact of the build. Te end result was a successful resin infusion of a flax fibre/Greenpoxy sandwich hull and deck with cork as a core material. Te Life Cycle Analysis supported the
choice of a green resin system and cork as a bulk laminate filler (akin to the use of Coremat or Soric) but highlighted that, without being able to improve the fibre volume fraction, little advantage is gained in the use of natural fibres over glass. 50% of the emissions were from the waste and the consumables used in the build. A further testament to the project is the amount of interest from industry: the students secured support from resin suppliers, fibre manufacturers and boatbuilders, including Green Marine and Composite Mouldings, and Te Green Blue, initiative of the Royal Yachting Association (RYA) and the British Marine Federation. Natural composites offer a more
sustainable method for construction of marine structures. Current research has indicated that there is a lot of promise
for these materials and show that they have comparable properties to the standard composite materials. Further to these mechanical properties it is also seen that they tend to be cheaper, more sustainable, and produce less emissions during manufacture; however, more research is required for them to become a regular part of the marine industry including; fire performance, developed manufacturing processes and long term durability. It is hoped that this article has inspired some boat designers to use these materials in the near future and support the ongoing research aimed at providing sustainable composites. SBI
Acknowledgements The authors would like to give their sincere thanks for the support offered by Amorim UK, Biorenforts, Bioresin PTY Ltd, Composite Mouldings Group, Formax, Green Marine, Matrix Composite Materials Company, Sicomin, REIDmarine, RS Sailing, RYA, Sustainable Composites Ltd
and Te Green Blue. 1
BRE & NetComposites, Green Guide to
Composites., BRE bookshop, 2004 2
Hammond G.P , Jones C.I. Inventory of
carbon & energy (ICE), Technical report, Sustainable Energy Research Team,
University of Bath, 2008 3
Malmstein, M., Chambers, A.R. and Blake,
J.I.R. (2013) Hygrothermal ageing of plant oil based marine composites. Composite Structures, 101, 138-143. (doi:10.1016/j. compstruct.2013.02.003).
Ship & Boat International May/June 2013
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90