"That was an outstanding display in tough conditions. We just grafted in the manner we have all season and our defensive line forced Christchurch into errors," Ratcliffe said.
"I'm proud of this group of men. No matter what happens on Sunday this has been an absolutely incredible season. St Peter's will be a tough side but it will be a really good final," he added.
As has been the case for most of this season Napier's scrum was dominant today. The Napier forwards carried well.
Napier opened the scoring after just four minutes when gutsy blindside flanker Josh Gimblett, a third-year first XV player crashed over after superb phase play from the engine room.
Similar patience led to Sheridan's first try in the 14th minute which second five-eighth Keegan Christian-Goss converted to give Napier a 12-0 lead.
By the time tighthead prop Patrick Teddy scored his try in the 19th minute Napier were putting eight and nine phases together on a regular basis. Napier led 17-0 at halftime.
Christchurch knew they had to score first in the second half to stay in the hunt. Hooker Henry Craw scored from a pick and go move and first five-eighth Cullen Moody converted.
Napier retained the ball for 11 phases during the buildup to Sheridan's second try in the 56th minute which Christian-Goss converted.
Christchurch had a glimmer of hope when prop George Roy-Smith scored in the 60th minute.
But that hope was dashed when Sheridan offloaded to first five-eighth Henry Williams who scored the final try. Christian-Goss was again on target with the extras.
While all of Napier's players deserve praise for the effort produced the Thompson twins, captain and hooker Tyrone and centre Leo, pushed Sheridan hard for player-of-the-match honours.
Busy No 8 Luke Russell and lock Tiaki Fabish impressed with their ability to force turnovers. Roy-Smith was the best of the Christchurch forwards and wingers Riwai Couch and Ryan Barnes made the most of their limited opportunities.
Moody congratulated the Napier players on their outstanding defensive work and strong carries.
St Peter's College pipped Hamilton Boys' High School 8-7 in their semifinal.
Scorers:
NBHS 31 (Jack Sheridan 2, Patrick Teddy, Josh Gimblett, Henry Williams tries; Keegan Christian-Goss 3 cons), Christchurch Boys' High School 12 (Henry Craw, George Roy-Smith tries; Cullen Moody con). HT: 17-0.