Wanganui's best hope, Henry Collier, began watchfully and by the next morning was eyeing his first 50 of the Hawke Cup when he was trapped in front by Bacon.
Wanganui manager Justin Lock was not impressed with the decision given how high the ball struck the pads.
Wanganui had re-jigged their lineup with Robbie Power promoted to No5 while regular opener Max Carroll followed him, but after Collier's departure no one could get going as Bacon, McLean and Caleb Gaylard all finished with profitable returns.
In reply, Wanganui's Nick Blundell picked up an early scalp after lunch yesterday, before the rain set in again for a brief period and more exercise was got by those running the covers onto the pitch.
Blundell continued after the resumption before in-form batsman Dion Sanson took control of proceedings with a well-measured 50.
However, Horowhenua-Kapiti experienced some wobbles as captain Dominic Rayner got Sanson to stab at a low full toss and send it straight to the keeper's gloves, then he picked up Bacon almost immediately with a plumb lbw.
However, with only a handful needed to pass Wanganui's meagre total at tea, Horowhenua-Kapiti looked the most likely to take competition points away from the match with around 40 overs remaining for a 7.30pm finish.