Six beachgoers including Micky Free's wife Gemma all entered the water at Reighton Gap, near Filey to help the three swimmers who were seen getting into difficulty last Thursday.
Former professional rugby league player David Fell, 55, from Wigan, died in the tragedy after being dragged over 50 metres from the shore, but the rescuers, who included a Yorkshire swimming champion, managed to reach his teenage son and daughter and pull them to safety.
The RNLI's Filey lifeboat arrived at the scene soon after and retrieved Mr Fell from the water before crew members attempted CPR.
Mr Free, who was at the beach with his children and another family, sent his drone to hover above the casualties and guide rescuers to them.
He has questioned why there is no signage at the beach, which is close to the Reighton Sands caravan park, warning of the dangers of rip tides.
"There were six people who went into the water after them and without them, those children wouldn't be alive.
"We noticed a woman next to us shaking her hands and there was a bit of a commotion, but we thought she was just panicking. Then we saw people jumping up and down, telling the swimmers to come back. We could see David Fell and we knew then that something was wrong.
"My wife went to the shore and went in after the dad and son, who had been carried off to the right, with another woman who we later found out was a champion swimmer. That woman's husband went to the left to get the girl.
"I got my drone out, set my phone up and sent it out and I could see them. The boy was laid like a starfish and was floating, and they were both getting tossed around. The man kept disappearing. Gemma and the woman managed to get to the boy and bring him back in, and she went out again to his father. She thought she was close to him, but he was about 50 metres out. From the drone I could see that his head kept going under and then popping up somewhere else.
"There was nothing anyone could have done to reach him until the lifeboat got there.
"The girl was the first to be pulled out, and she was in quite a bad way - they gave her oxygen. The boy was conscious and they took them to hospital.
"It was awful - it has affected my wife a lot. All we could do was watch as they were pulled around all over the place."
Mr Free later gave police his drone footage and was told by officers that the children were badly shaken but recovering in hospital.
"Later that day there were still people going into the sea and letting their children swim - I thought they were mental. It's notorious for rip tides and there are no signs."
On the same afternoon RNLI lifeguards at Withernsea rescued a man and three teenage girls from a 'flash' rip that appeared within a designated swimming zone, and on July 15 a group of six teenagers were injured at Hornsea South Beach when they were carried out to sea by a rip current and tossed against a groyne.