Such men often took to the sea in small boats looking to gather kaimoana for their families, he said.
Participants on the course ranged in age from fresh-faced school students through to seasoned fishermen in their 50s.
"One of the key things is skippers' responsibility and once you've done the course you can't plead ignorance. If you own the boat you've got to take responsibility for everyone on the boat.
"The other key message is wearing lifejackets. If someone doesn't want to wear a lifejacket, then they don't go."
Thanks to sponsorship from Ngai Te Rangi, and marine manufacturer Hutchwilco, all participants on the course were presented with a Hutchwilco lifejacket.
Mr Hewitt said he was living proof of the saying "if you stay afloat, you can stay alive".
During the three-day course, Mr Hewitt taught survival skills to the participants at Baywave swimming pool.
"I had a couple of non-swimmers so we went to Baywave which is a controlled environment. I showed them a couple of survival strokes and I showed them how to survive and conserve energy and keep the heat in."
Mr Hewitt got the participants to swim a couple of lengths and tread water for half an hour before showing them how to use side-strokes to conserve energy and how to huddle together for warmth and safety.
Mr Hewitt works as an ambassador for Water Safety New Zealand and New Zealand Post, the two sponsors of Kia Maanu, Kai Ora - marae-based Day Skippers' Course.