The only way these particular TWO ships could be “off course” is if they wanted to be “off course”.
They would not want to be off course. These were Riverine Squadron boats, not SEALs or SWCCs. These boats are not “special ops” in any way, especially not with only their standard crew of five on each boat. These boats are basically doing a USCG function, since the USCG has mostly departed the region.
My thought also.
Not just both off course... but what are the odds of both losing all ability to communicate?