The American-born swimmer posted the fifth-fastest time in this morning's heats, with a new national record time of 25-point-one-nine seconds.
His semi final is due to start tonight just before 7.45.
Sycerika McMahon placed second in her heat of the womens 200-metre medley, but in a time not fast enough to progress to the semis.
Fiona Doyle will be in action in the final of the Women's 100-metre Breaststroke this evening.
That race is due to start shortly before 7pm.
