On 10 August 1803, Cato left Sydney in the company of the ships HMS Porpoise and Bridgewater bound for India. On 17 August the three ships got caught near a sandbank, 157 miles north and 51 miles east of Sandy Cape. With shrinking leeway, both the Cato and HMS Porpoise were grounded. Bridgewater sailed on, despite knowing that the other two ships had come to grief. The crew and passengers of the other ships were able to land on a sandbank as both their ships broke up.
On 26 August 1803 with no sign of rescue, Porpoise passenger Matthew Flinders and Captain John Park of the Cato took the largest cutter (which they named Hope) and twelve crewmen and headed to Sydney to seek rescue. Through marvellous navigation, Hope made it to Port Jackson by 8 September. Three lives were lost in the joint shipwreck. The remaining passengers were rescued.