Boats passed as family yelled for help

A beautiful day on the water almost turned to disaster for a Perth family of four when their 22ft timber boat started sinking on the Swan River.

And another sailor was rescued in the "nick of time" after he got into trouble 92km off Mandurah on Saturday evening.

The 46-year-old was winched from his sinking yacht to the RAC rescue helicopter as it became dark and the weather worsened.

Martin Ferreira, wife Anje and children Tom, 7, and Monique, 2, were heading from Garden Island on Thursday when their engine cut out and the boat, built in the 1970s, started sinking in Mosman Bay. The batteries were submerged, cutting power and communications.

Mr Ferreira said despite bailing for an hour, he and his family were terrified as they stood knee-deep in water on the deck.

"I tried to wave to boats that went past, but they didn't take any notice," he said. "It was looking pretty grim."

Mr Ferreira was surprised that at least four boats passed by as close as 50m from the family despite frantic waves and shouts.

Eventually a couple, one of them named Bill, towed them to the Flying Squadron Yacht Club.

"The water was a foot above the deck and I reckon we would have had another half an hour before sinking," he said.

At the club, another good Samaritan named Morgan got their boat on to his trailer and they found a 32cm split in the hull.

Even though the Mateka had lifejackets and safety devices, Mr Ferreira was thankful the drama was not on the open ocean.

"Nothing happened out there, which was very fortunate with little kids onboard," he said.

Most of all, Mr Ferreira was grateful to those who helped.

The sailor in trouble off Cape Bouvard also thanked his rescuers after he set off an emergency beacon about 4.30pm.

The man, who did not want to be named, then put on a wetsuit, wrapped himself in a blanket and sat on his sinking boat waiting.

"I was very lucky," he told Seven News. "It was going on dark and apparently they can't winch people out of the water after dark, so it was split-second timing."

It is believed an Orion plane diverted from searching for the missing Malaysia Airlines flight first spotted him after he set off smoke and parachute flares.

RAC critical care paramedic Clint van der Westhuyzen said the weather started getting nasty and night was falling.

But the sailor, who lived aboard, was well-prepared with an EPIRB, wetsuit and floatation.

"I've lost my home but my life is still intact," the sailor said.