The Otago Boys' High School pupil won the MVP award for being the most successful male competitor at the New Zealand surf life-saving championships.
Trembath is a member of Labara's Osca swimming squad and used his superior fitness to dominate his opponents.
Trembath won three of the four gold medals in his men's under-16 grade in the ski race, surf race and the iron man.
He demonstrated his class in the iron man by the way he negotiated the big surf that made life difficult for his opponents.
Trembath played a key role in St Clair's seventh placing in the aggregate points teams event with 35 points. It was St Clair's best performance at the national championships since 1995.
Trembath moved up two grades and won a silver medal in the open men's surf race. Other members of the St Clair team were Adam Simpson, Andrew McMillan and Jamie Mowat.
He also won a gold medal in the men's under-19 tube with Mowat and a bronze medal in the board rescue with Hamish Taylor.
Trembath was one of four St Clair competitors who were named in the New Zealand squads. He was joined in the development squad by Jessie Schneiders, while McMillan and Carina Doyle were named in the senior squad for the world championships in France next year.
Schneiders was a key member of the four-woman St Clair under-19 team that retained its national title. The other team members were Doyle, Lulu Schneiders and Jordy Fogarty.
Otago competitors won 13 medals at Mount Maunganui - five gold, four silver and four bronze.
Other silver medals were won by McMillan and Simpson in the open men's tube rescue; Doyle and Jessie Schneiders in the under-19 female tube rescue; and Angus MacKenzie and Arthur Ibbotson in the under-19 double ski race,Bronze medals were won by Steph Laughton, Doyle, Jessie Schneiders and Fogarty (open female surf teams' race); Doyle (under-19 female surf race); and Bailey Brandham (under-16 male surf race).
