Police have criticised the "sheer stupidity" of three unprepared divers who were taken 5km out to sea when the motor on their inflatable craft seized on a remote stretch of coastline.
The Palmerston North men in their 40s, were diving off Akitio Beach, south of Dannevirke when they got into trouble about 4.30pm on Saturday.
They had no anchor, life jackets, radio, cellphone, torch or locator beacon on board and were carried quickly out of sight.
"Very strong north westerly winds could have carried the inflatable a long way out to sea," Central District Operations manager, inspector David White said. "It was just very fortunate that someone spotted them from the shore.
"They were very lucky and others need to learn from their mistakes."
A helicopter and local fishing vessels helped police search for the boat, which was discovered by a member of the rescue party, 45 minutes after it was last seen.
All three men were uninjured and had managed to stay inside the inflatable craft.
"It was all over pretty quickly for them, but you see the worst case scenario happen all the time," Mr White said. "It doesn't take long to go from normal to disaster off the coast. It's a matter of moments.
"If you look back at inquests, there are cases where the boat has never been found and the bodies have never been found."
Mr White said boaties needed to be prepared.
"Anyone in charge of a boat needs to take responsibility for themselves and their passengers, and this means proper safety precautions. Heading out to sea without any life jackets, safety beacon, a radio, or a cellphone is just sheer stupidity.
"I know the gear costs money, but to be honest, if you can't afford it perhaps you shouldn't be going out. After all what cost is a life?"