 The patrol boat fleet began a mid-life refit program in October 2015, in order to extend hull life until a replacement class of larger vessels enters service from 2022.Patrol boats are being refitted two at a time in Singapore, with the RAN chartering the s "Cape Byron" and "Cape Nelson" from mid-2015 until the end of 2016 to supplement naval patrol boat availability.During work on the first two patrol boats, the estimated cost of work-per-vessel doubled to A$7 million.