▁plan es ▁effectively ▁ham per ed ▁her , ▁and ▁she ▁returned ▁to ▁her ▁new ▁base , ▁F rem ant le , ▁Australia , ▁empty - hand ed . ▁ ▁Dep loyment ▁to ▁Australia ▁ ▁The ▁Mal ay ▁Bar rier ▁was ▁the ▁site ▁of ▁Gren ad iers ▁fourth ▁war ▁pat rol ▁from ▁ 1 3 ▁October ▁to ▁ 1 0 ▁December . ▁After ▁lay ing ▁a ▁mine field ▁off ▁H ai ph ong , ▁Ind och ina , ▁the ▁sub marine ▁made ▁an ▁un success ful ▁attack ▁on ▁a ▁large ▁fre ighter . ▁During ▁the ▁severe ▁depth ▁charg ing ▁which ▁followed , ▁sea ▁water ▁se ep ed ▁into ▁the ▁batter ies ; ▁Gren ad iers ▁crew ▁suffered ▁head aches ▁and ▁n ause a ▁from ▁ch lor ine ▁gas ▁poison ing ▁for ▁the ▁remainder ▁of ▁the ▁pat rol . ▁On ▁ 1 2 ▁November , ▁she ▁attacked ▁and ▁s unk ▁by ▁tor ped o ▁the ▁rescue ▁t ug ▁ ▁() ▁off ▁the ▁coast ▁of ▁Vietnam ▁( 1 1 ° 1 8 ' N ▁ 1 0 9 ° 0 2 ' E ). ▁To ▁increase ▁the ▁mis ery , ▁on ▁ 2 0 ▁November ▁Gren ad ier ▁sp otted ▁a ▁- class ▁aircraft ▁car rier , ▁esc orted ▁by ▁a ▁cru iser ▁and ▁a ▁destroy er , ▁heading ▁through ▁the ▁Stra it ▁of ▁Mak ass ar ▁too ▁distant ▁to ▁shoot . ▁Gren ad ier ▁sur fac ed ▁to ▁radio ▁the ▁aircraft ▁car rier ' s ▁location ▁and ▁course ▁to ▁F rem ant le ▁sub marine