Cutler added to her 16/17-year-old girls’ 100m backstroke gold from the second day of the competition with another first place, this time in the 200m backstroke.
She clocked a time of two minutes and 16.86 seconds for the four-length race, which was a new personal best.
Dekker, meanwhile, added a 200m butterfly silver to the 12/13-year-old girls’ 100m freestyle gold and 50m butterfly silver she had previously won. She also claimed a new lifetime best, finishing in 2:25.33.
The competition at Ponds Forge ends on Sunday.