"When you're around good people it gives you a lift, and I think our school has been blessed along the way with a co-operative and supportive board of trustees."
Simes, previously the deputy principal of Whanganui Intermediate, said the majority of principals were male when he started.
"In recent times we've seen an almost complete reversal of that."
Office administrator Jean Craddock said she had been "inherited" by Simes, and that the school had grown under his leadership.
"He must be one of the longest-running male principals in Whanganui, and there aren't many left," Craddock said.
"It's been dominated by females, and he has been dominated by females here too.
"Our staff has grown from 13 up to 20, and that's down to Geoff, who's been terrific."
Former deputy principal Jenny Coss said Simes' biggest strength was "never rushing into a decision".
"He will always wait and talk to people and think about things," Coss said.
"I used to teach at country schools in the past, and this is the closest you can get to that feeling.
"There's always been a family group, and people don't tend to come and go."
Mike Dewson, who worked at Durie Hill School for 41 years, said it had been a pleasure to work with Simes.
"He's a lovely fellow and a very deep thinker," Dewson said.
"Geoff is great at forward planning, and that, in turn, makes teachers settled and calm.
"The actions that he's taken have given Durie Hill School a really good reputation, and when you tell people that you used to work there, they inevitably say 'oh, that's a good school'.
"In a large part, that's down to Geoff."
