"It's safe to say we couldn't have done this without the McConaghy team," said Cameron, acknowledging McConaghy Group’s key role in this remarkable project.


McConaghy composites challenge the Ocean’s Deepest Depths


Explorer-filmmaker James Cameron chose the McConaghy Group when he needed to rely on composite materials  for his record-breaking submarine dive 11 kilometers to the bottom of Challenger Deep, the deepest part of the world’s oceans, located at the southern end of the Mariana Trench.


Crucial to the design concept of this unique vessel was its ability to descend under its own weight, remain at the bottom at neutral buoyancy, then by releasing ballast, rise again to the surface. The extreme pressures would cause the main structure to compress at the bottom then expand again at the surface by as much as 65mm over its 6m length. Calculating the varying buoyancy and then finding a material that would withstand the pressures and stresses and provide the ideal buoyancy, was the key.


A rigorous testing process established by Acheron Project leader Ron Allum was crucial to the success of the project. With pressures at this depth reaching 16,500 psi, equivalent to the weight of 88 double decker busses stacked on top of an area of just 1 square foot, the slightest imperfection could lead to catastrophic failure, with no chance of recovery. This intense pressure would cause 1 litre of air at the surface to compress to just 0.8ml at the bottom of the trench, a reduction in volume to less than 1000th of its size at sea level. Any air trapped in the laminate or parts subjected to this pressure would cause the submersible to implode, leaving James Cameron trapped in a 1m diameter steel sphere at the bottom of the trench with no possibility of rescue.


Fully aware of the high stakes, Ron Allum started working with a range of composite suppliers and manufacturers from the USA and Australia and tested samples provided by these manufacturers in a pressure vessel located at a university in the USA, the only know pressure vessel capable of duplicating these pressures.


Unable to find a commercially produced material to meet his requirements and perform under testing, Ron resorted to designing and manufacturing his own composite high density syntactic foam material, later patented as ISOFLOAT®. This material was strong enough to provide the structural back bone for the submersible, eliminating the need for a metallic chassis, as well as provide the desired buoyancy characteristics and cope with the extreme conditions at the bottom of the ocean.


ISOFLOAT® is produced in building blocks similar to large bricks, over 250 of these bricks needed to be structurally bonded together to form the structural core of the vessel or “main beam”. The bonding of these blocks presented the next challenge for Ron and his team which lead him contact McConaghy amongst other composite manufacturers. Taking time to understand the requirements of the project and objectives that Ron needed to achieve allowed McConaghy to develop a bonding process that they believed would achieve these objectives. Initial test samples were produced, Ron and his team subjected these samples to their testing regime, and the results proved successful. McConaghy built larger parts for testing which again proved successful. Ron soon engaged McConaghy to start construction on the main beam.


In parallel Ron and his team were working with other composite manufacturers and testing their product, the success of the McConaghy product contrasted with the failures of the other suppliers. Ron and James Cameron progressively gained confidence in the McConaghy team, reassured in their ability to achieve what others could not. The job list for the McConaghy team grew longer and longer as the dead line for the dive approached and other composite specialists from around the world could not deliver on the required quality. Ultimately McConaghy produced every component on the image that was painted green including the thruster units, doors, access panels and battery housings, as well as the main syntactic foam beam which supported James Cameron in his 1m diameter steel ball.



"It's safe to say we couldn't have done this without the McConaghy team," said Cameron, acknowledging McConaghy Group’s key role in this remarkable project.


The McConaghy team was able to succeed where others failed due to over 40 years experience with testing and developing techniques in composite construction for use in a wide range of applications, especially in challenging marine environments.


In the mid 1970’s McConaghy Boats was the first company to apply aerospace materials to the marine industry. Prepreg carbon fiber and nomex honey comb cores had only been used by NASA prior to John McConaghy adapting these materials for use in high performance racing yachts. The most technically challenging aspect of building structures with honeycomb cores is the bond between the honey comb surface and the carbon fiber skins. The volume of air contained in the cells of the honeycomb core works against the fundamental need to get the skins to adhere to the core under a vacuum bag and at elevated temperature.


The key to the success of the high performance racing yachts that McConaghy Boats has build over many decades has been the strength of the bond that has been achieved between the honeycomb cores and the carbon skins, allowing structures to be lighter stronger and stiffer than any other material. By the mid 1980’s McConaghy Boats had built the largest honeycomb cored structure in the world, numerous McConaghy built maxi yachts still dominate the toughest races in the world many years after they were launched.


In order to achieve this success McConaghy has been relentlessly researching testing and refining techniques for removing air and voids from composite structures during the laminating process for decades.


This research and in depth technical understanding of composite materials is what gave McConaghy the edge when James Cameron and Ron Allum approached the McConaghy team requiring a composite structure which contained no voids or air entrapment.


Following the successful decent and assent to and from the bottom of Challenger Deep, James Cameron’s DEEPSEA CHALLENGER won the coveted Good Design Australia “Good Design Award of the year” for 2012. Along with Acheron Project, Design + Industry and Finite Elements

McConaghy Boats were among 4 contributors to this project who received a specific mention in the award, and specific acknowledgment from James Cameron.




More information please visit: www.deepseachallenge.com