But as they drifted further out to sea the lifeguard "panicked and took his board from the patient and left him in the water".
Mr Logan then decided to take action and swam out to both the swimmer and lifeguard.
"The hardest part when I reached them was trying to get the lifeguard off the board - the language barrier made it difficult for him to understand that I was an experienced lifeguard and felt confident to carry out the rescue," he said.
He got the swimmer onto the board and paddled him back to shore.
The local lifeguard arrived shortly after. He explained that he was tired and had lost power in his arms.
Mr Logan later discovered the man he had helped rescue was a fellow New Zealander, from Cambridge, and he was extremely grateful for his help.
The rescue followed another by fellow Paekakariki lifeguard Aaron Lynch, who saved a schoolmate.
The 17-year-old Mr Lynch saved was part of a group of students travelling to Auckland for a cross-country competition when they stopped in Taupo.
Mr Lynch was relaxing in a hot pool when he heard a call for help and saw a body being dragged out of the water.
"I don't really remember getting from the spa to the other pool, only that I sling-shotted off a pole along the way," he said.
He performed CPR and after three cycles managed to revive his schoolmate.
The student recovered in hospital overnight.