"This was his full-time job and he only bought the boat a few months back. He came down south to get it but I didn't catch him because I was in hospital.
"He was a good son and would come and see me whenever he could. It would be a surprise knock at the door or phone call whenever he was coming down.''
Mr Cosgrove, a father of two, bought the Governor on behalf of owner John Brown, from Westfleet, at the beginning of the year and began fishing from it after Christmas.
His father added: "The waters are very unforgiving out there on the West Coast. He was a lovely son and this is just a terrible accident. He just loved nothing more than being out on the boat.''
Police launched a full scale search after the boat was reported missing and today found what they believed to be wreckage of the vessel 2.5km off shore from Yates Point in 50 metres of water.
Due to forecast severe weather conditions it is likely that no dives to the wreckage will take place until after the weekend.
Nirvana Reynolds, from Blackball, moved to the West Coast last year and briefly attended Greymouth High School. Before he moved he attended Waitaki Boys High School in Oamaru.
Nic Hill, deputy principal at Waitaki Boys said: "Nirvana was well liked by his peers and a very athletic young boy.
"He was outgoing and was always going to be someone who got a job doing something outside. His favourite subject was agriculture and he always worked hard.''
Police said Nirvana's mum was 'shocked and upset' by the tragedy, and asked for privacy as she came to terms with the terrible news.
Senior sergeant Cynthia Fairley, Western Southland police sub-area commander said with the tide and wind at the time of the tragedy, police doubt the men made it ashore.
She said officials were considering using police or navy divers, or possibly an underwater device with a camera to carry on the search.
She said: "The location of the boat was discovered after a diesel spill was spotted, as well as an empty liferaft and a buoyancy ring. There was nothing on the liferaft to lead police to believe that the men had managed to get into it.''
A spokesman for Maritime NZ added that preliminary inquiries were under way, but it was too early to speculate on what might have gone wrong.
- Additional reporting Greymouth Star