Aircraft spent much of yesterday looking for Mr Rusbatch, focusing on a large area between Mayor and Motiti Islands.
The search continued overnight, with the Navy vessel HMNZS Pukaki searching the Mayor Island shoreline with the aid of searchlights.
Mr Rusbatch's sister Jane Willing told the Herald the family were hoping Mr Rusbatch, who has several daughters, had made it to land.
"He's a very strong swimmer and he's used to being at sea. So, I've just got my fingers crossed, with his daughters, that he's swum somewhere - to one of the islands. That's what we're hoping for,'' she said.
Mr Rusbatch runs charter trips between Russell and Tauranga. Mrs Willing said he had been running his charter business for "many years''.
Police were urging anyone who had seen the Honfleur since Sunday, after it left Tauranga, to contact them urgently.