The Royal Australian Navy officer overseeing the planned Collins submarines Life-Of-Type Extension (LOTE) program says hull fatigue studies had found the Collins boats could achieve the extended operational life needed while new nuclear subs enter service.

Executive director of the Collins LOTE program, CAPT Dan LeRaye said there were five lines of effort in the scoping studies for the proposed Collins LOTE program, one relating to hull fatigue.

“That was pretty much a deal breaker,” he told the Submarine Institute of Australia (SIA) conference in Adelaide on November 9. “If the hull couldn’t go the extra distance, there was no point in doing life extension. I know that work was done. I know the answer was favourable, and I know the answer was peer-reviewed by both (the US Navy’s) NAVSEA, and Saab-Kockums.”

All six Collins boats are to undergo a LOTE, beginning with HMAS Farncomb in 2026. The last boat – HMAS Rankin – is scheduled to be decommissioned in 2048. Under LOTE, electric motors, diesel engines, and generators will be replaced, as these items present a medium-to-high risk of causing the Collins boats to not meet the planned withdrawal dates.

CAPT LeRaye said LOTE was not just a case of replacing systems in the Collins class with the same technology as had been proposed for the abandoned Attack class boats. “LOTE is replacing these systems because we must,” he said. “We must do it to mitigate or to eliminate in essence the highest risk to achieving the amended planned withdrawal date.”

He said that, at the time equipment choices were being made for LOTE, it had made sense to opt for technologies and products as similar as possible to those planned for the Attack class. That could include the optronic mast and periscope planned for the Attack class and still under government consideration for installation on the Collins boats.

“We have completed concepts designs for an optronics capability to replace the search periscope. We are ready to go if government do make a decision to proceed,” he said.