Although there have been "a number" of unconfirmed sightings of a similar vessel - a 6.1m Wharram-design catamaran, painted white, with white sails and the number T878 in black on the sail - in the upper North Island, but there hasn't been any since the New Year.
Chapman said a few Kawhia locals had told him that they knew Langdon didn't intend to come back from his sail.
Without the appropriate safety gear like no back up outboard motor and emergency locator beacon, Chapman is worried for the pair's safety. He said the police's description of Langdon as "foolhardy" is accurate.
"He has greater confidence in his sailing skills than [is]warranted."
Chapman claimed Langdon told Ariane and Que to stay onboard their yacht when they were moored in Port Villa Harbour while the 2014 category 5 Vanuatu cyclone hit. This is despite advice to leave the boat and find safety onshore.
"Within a couple of hours their catamaran was destroyed on the rocks with them on board. They were taken to hospital with serious injuries.
"That's the kind of person who Alan is."
Chapman said it was after that incident Ariane decided to end her relationship with Langdon.
With Langdon's imminent arrival Chapman was concerned that the New Zealand authorities had not made a formal request to Australia to take up the search. He said the Langdons are also not listed on Interpol's missing persons website which means they haven't received an alert.
"The website is updated frequently and they're not on it.
"I don't get why they're not pushing it a little bit more."
A police spokeswoman said Australia had been advised of the circumstances through Interpol. She said police remained hopeful that Langdon would make contact with them.
"There still remains no evidence what direction Mr Langdon went after he left Kawhia Harbour so it is still one of many scenarios that are possible."
Chapman headed back to Kawhia last night to speak to another boat owner.
"I just wanted to see what his impressions were. He didn't think the weather conditions at the time were that inclement. The conditions weren't considering particularly dangerous
"That boat could capsize, it could tip, but it can't sink."
Langdon came from a family of sailors and had been on the water since he was 4, Chapman said. Both his dad and grandfather were keen yachtsmenand Langdon was brought up in Kawhia. Chapman said Langdon would easily find work doing various types of manual labour like building and fruit picking.
"Kawhia is historically a fishing village. There were some hard men there, your mountain men sort of guys. That's the style of maledom."
