The Collins Class submarines' need was for externally mounted casings with the often conflicting requirements of high strength and low weight. Combine these requirements with the need to incorporate floatation capability to assist with stability and you have a problem requiring a high level of design and engineering expertise.
BAC possesses these attributes and was therefore chosen by the Australian Submarine Corporation (ASC) to undertake the design and build of the 11 sections of casings covering the full length of the 78metre submarine. Each section is approximately 7metres*4metres*2metres and can include up to 2,000 pieces of critically positioned laminates. Attachment to the steel hull also required highly accurate alignment and positioning of some 50 bolt holes per section and out of approximately 2,000 holes for the complete contract, not one hole exceeded the very tight tolerances!
Consistency, cost-control and quality are BAC's key attributes in helping customers meet their requirements and assisting with solving their problems. BAC has demonstrated these attributes in having the weights of casings repeated within 1% and resin to glass rations within 2% using our in-house developed techniques.
So successful was BAC in meeting the expectations of both the ASC and the Royal Australian Navy that we were also chosen to undertake the design and development of the new and revised casings for the recent "Noise Reduction Programme". BAC developed the laminate design for the four sections and verified these using Finite Element Analysis (FEA).