A Nelson man is three-quarters of the way through a 19-day trip to solo circumnavigate the South Island in a 3.8-metre rigid hull inflatable boat to raise money for a mate with a rare disease.
If successful, David Puklowski will be the first person to make the journey in such a small motor boat.
Puklowski set out from Nelson on April 1 and a live-tracker showed him near Oamaru on Thursday .
He came up with the idea for the challenge as a way to do something for his mate, Russell Blowers.
Blowers was born with X-linked hypophosphatemic rickets, a condition he inherited from his mother.
It is a reasonably rare disease which stops him from absorbing vitamin D and causes his kidneys to lose phosphate which results in skeletal problems from his bones growing abnormally.
It means the long bones of his extremities (tibia, femur, radius and ulna) become bowed. Abnormal parietal flattening and frontal bossing occur in the skull and the cartilaginous attachments of the ribs become prominent.
Spinal curvature, muscle pain, profuse sweating and general tenderness of the body were all signs and symptoms of rickets.
Blowers had his first corrective surgery on the tibia and femur in both legs when he was 2 years old and had it repeated when he at 10 and 15.
Since then he has required surgery on his nasal passages twice and has had extensive work done on his jaw and teeth. The condition had also directly affected his breathing and hearing.
Soon Blowers will undergo the first of three operations he will need over the next two years.
"Dave came to me about a year ago and told me he was going around the South Island in a little dinghy, that scares the hell out of me, and Dave said to me that he would like to try and raise some money and raise some awareness for my condition," Blowers said.
"I just battle on normally with this kind of thing. What Challenge For A Mate is going to do for me is allow me to lose some of the stress when I have operations. Currently the pain is so great that I can only work a short amount of time each day."
Puklowski hoped the trip would not only help out his mate but encourage others to set themselves a challenge for the sake of their friends.
Challenge For a Mate was about inspiring ordinary people to take on challenges to help friends in need, he said.
"We've all got mates that need a little bit of a hand every now and then and that's what it's all about."