A boat has capsized near the North Mole bar at the mouth of the Whanganui River.
Police were called at 2.50pm on Wednesday after reports of the boat having flipped in the sea off Castlecliff.
Two men were on the boat and jumped overboard as their vessel went vertical from the impact of a wave, which was witnessed by some on shore.
One of those was Ken Carlyle who lives near the Morgan St wharf.
Carlyle said he "knew they'd go" after he watched the boat try to cross the bar.
"The boat was tipping up too far on every wave they hit.
"They just got level with the end of the mole, and that was it.
"It just disappeared then you could see it upside down and the white hull in the water."
The two men, who were both wearing life jackets, were pulled from the water by Steve Lees, Andy Hall and Alan Hislop on Whaddayathink.
The trio had been out fishing and were returning to the bar when they heard a call on the radio that a boat had overturned.
Shortly after the group spotted the men in the water.
"We got on the right side of them, threw a rope and pulled them in one at a time," Lees said.
Despite having their boat overturn and ending up in the sea, he said the men were calm.
"They were pretty laid back guys.
"They were just out there having a swim.
"It's great they had the right gear with with them and didn't start panicking, that's the worst thing they could've done."
Coastguard Wanganui and Wanganui Surflife Saving member Jamie Newell said recently the bar has gained a build-up of silt which can create problems.
"When you start getting towards the lower tides, you get a low more wave action getting pushed up because there's not as much water in the bar as there has been in previous years.
"It's been getting gradually worse over the last couple of years but this year is going to be quite noticeable on the low tides."
Newell recommended anyone heading out in their boats should be crossing the bar one to two hours either side of low tide.
Constable Trevor Scarrow said the incident was a reminder for everyone to ensure they're safe while boating and have the right equipment.