Students had to apply in writing and submit a letter of recommendation to participate in the adventure before undergoing a gruelling afternoon of tests - fitness, cooking and problem-solving, Mr Carr said.
"Participants carry nearly everything they need on their own backs, so it must be great to crawl into their tents at night. Sadly for them, on at least one night, their tents are taken away and they are given a tarpaulin.
"Then as individuals they have to build their own bivvie and spend the night away from their teams."
Other diverse challenges on the adventure involved MasterChef cookery, sheep drafting, shopping, and paintball and claybird shooting.
Rathkeale principal Willy Kersten said one of the defining features of the Trinity Schools was the unique system of single sex education at years 9 to 11, followed by co-education in the senior college at years 12 and 13.
"The year 12 Odyssey is a unique physical and mental challenge that allows students from our two schools to develop their collaboration and co-operation skills. The hope is that these skills might be put to good use next year in their studies, on the sports field or on the stage," he said.