Botany Bay tragedy: Boatswain Stuart Collings is killed and brother-in-law Darren Curmi is injured after his boat is hit by a whale and overturns

Harrowing new details have emerged about how a fisherman desperately clung to his dying brother-in-law for 45 minutes after a huge whale landed on his boat and threw him into the water.

Water police rushed to the scene of the accident at Cape Banks in La Perouse, south of central Sydney, about 6am on Saturday after reports that two men were in the water in Botany Bay.

Stuart Collings, 61, and his brother-in-law Darren Curmi, 53, were thrown into the water in the dark.

Mr Collings fell unconscious during the impact as Mr Curmi kept his brother-in-law afloat for 45 minutes, desperately calling for help.

Footage has emerged of the stricken ship making laps around the area as the men waited to be rescued.

Mr Collings was pulled from the water but sadly died at the scene despite desperate efforts to revive him.

Mr Curmi, 53, was rescued and taken to St George Hospital in a stable condition.

It is understood the brothers-in-law had been on their fishing trip for just half an hour when the tragedy occurred.

A man died and another was taken to hospital after his boat hit a whale and overturned off the coast of Sydney (pictured: water police and paramedics on scene).

At around 6am, water police were called to the scene and officers pulled the deceased man from the water, unconscious (pictured: emergency services near the Foreshore Road Boat Ramp).

Shocked witnesses, who were also on the water just off the heads of Botany Bay, said they heard a “big bang” before the 4.8m boat overturned.

“Something big came out of the water, it was huge,” one told the Daily Telegraph.

“It was still dark, but you could see this big black figure jumping out of the water.”

Acting Water Police Superintendent Siobhan Munro said the whale breached near or on the run-about boat, causing it to overturn.

“There are a lot of whales out there at the moment and there are a lot of examples of whales escaping next to boats… but this is a tragic accident,” he said.

Police Minister Yasmin Catley expressed her condolences to the late man’s family in a press conference later on Saturday morning.

“It is very early stage and we know very little information at this point,” she said.

‘[We] It was discovered early on that it was a whale. Who would have thought this would happen?

“It is terribly tragic and we feel for this family and friends.”

“This morning two boys got up to go out and have fun fishing, something I and most people in New South Wales enjoy doing, and ended up in tragic circumstances.”

The Foreshore Road Boat Ramp in Botany and surrounding roads were closed as police began investigating the incident.

It is understood the unconscious man held his unconscious partner in the water for 45 minutes while he called for help.

Witnesses said they heard a “big bang” before the 4.8 meter long boat overturned.

“Something big came out of the water, it was huge,” they told the Saturday Telegraph.

“It was still dark, but you could see this big black figure jumping out of the water.”

Officers pulled two men from the water at Botany Bay in Sydney’s southeast early on Saturday morning (pictured: rescue workers on scene)

The second man was pulled from the water and taken to hospital in a stable condition by NSW Ambulance paramedics (pictured: paramedics on scene).

NSW Maritime chief executive Mark Hutchings said an “incredible” number of whales were migrating along the east coast this year.

“When you’re on the water you have to be 100 meters away from an adult whale, and 300 meters if that whale has a calf,” he said.

“The whales are not there to harm anyone, but such interactions can happen.”