"I jumped up to the wharf to raise the alarm and then jumped into the water," he said.
He managed to hold the man against the side of the boat as Ms Warren, who had been waiting for a sober driver, discarded her heels to clamber down to the boat and leant over its rails to help. "As soon as I heard the commotion, it was a huge adrenalin rush," the waitress said yesterday.
With help from her friend Sam Grapes and another man, Chris Sparkes, the rescuers managed to haul the man from the water and into the back of the boat.
Taking control of the situation, Ms Warren performed a series of compressions on the man, managing to force out of his lungs the water he'd swallowed.
The rescuers then shifted the man into the recovery position, from where he was able to force himself to breathe.
"I was holding the guy's hand and I said to him, look, if you can hear me, we just need you to start breathing ... he squeezed my hand a little, so I knew he could hear what me and his friends were saying."
More than once there was no sign of a pulse and no breathing.
"We had a gap of 30 seconds when he was not breathing, so we got him back into the recovery position, I gave him about a compression and a half, and he started breathing again," she said.
A crowd of onlookers climbed on to the boat, some taking pictures with their phones, but were soon ordered away.
"With the number of people standing around screaming, it was hard to get through to the ambulance people and tell them he was actually in quite a serious condition," Mr Sparkes said.
"He was making noises and grunts, there was foam coming out of his mouth, and he had quite a big gash on his head ... there were actually a few moments when we thought he'd gone."
When emergency services arrived, the man was quickly loaded on to a stretcher and rushed to hospital in a critical condition.
Some time later, Ms Warren received a message that the man had regained consciousness.
"That was the first time I've saved someone who has drowned ... and I'm at the beach on patrol all the time," she said with a laugh.
Mr Carruthers said it was the worst experience of his 10 years on fishing boats, but it was fortunate Ms Warren had been "in the right place at the right time".
People in the area falling into the water at night had been an ongoing problem for several years and in a joint project with police in 2011, bars were equipped with flotation devices to use to get people out of the water. One person didn't want rescuing, having leapt into the water to flee the police and swimming to the other side of the inner harbour.
Napier police senior sergeant Dan Foley, a former lifeguard himself, said Ms Warren's presence made a big difference.
"We are really pleased there were people there who had expertise in first aid. It would appear the outcome was much better as a result of it."