The captain of the ill-fated Indonesian fishing boat carrying 89 illegal immigrants to Australia in December last year abandoned the poorly equipped vessel the night before it crashed up on Christmas Islands' treacherous shore.

A Coronial Inquiry being held in Perth today was told the boat, Siev 221, had sustained engine failure at numerous stages of the journey, including when it lost all power before crashing into rocks at Christmas Island just before 6am on December 15, killing up to 50 passengers, including women and children.

Counsel assisting the Coroner, Malcolm McCusker QC told the inquiry that the boat had meant to undergo engine repairs in Jakarta earlier that month but the owner refused.

Despite attempts by some of the Iranian and Iraqi passengers to ask if the boat had appropriate life jackets, some even offering to buy their own, they set sail with only 20 to 30 life jackets aboard, sometime after December 11.

Many of the passengers carried their own supplies as food and water aboard the boat was insufficient to see them through the three-day journey, Mr McCusker said.

It was during the rough journey that the boat began to take on water, often causing the small engine, described as being similar to a tractor's engine, to stop.

At one point the engine room was more than 60 centimetres deep in water and people had to form a human chain and use buckets to bail it out before the engine would work again, Mr McCusker said.

One of the four-man crew aboard the boat was a fisherman, Abdul Rasjid, who had been promised a "large sum for a fisherman" of 20 million Indonesian rupiah ($2210) for the journey.

As they approached the island, Mr Rasjid was left in charge to steer the unfamiliar boat, with very few directions. The captain then disembarked to board a second vessel that had been trailing the leaky fishing boat, just before midnight on December 14.

Mr Rasjid had been reassured that when they arrived someone would pick them up.

"He had never travelled to Christmas Island before," Mr McCusker said.

"...after the engine failed he could not do anything, just gathered and prayed."

A second crew man Supriyadi said he had been "duped", according to Mr McCusker.

"He had been told to look after the engine even though he had no experience in looking after engines... He had no experienced on boats, he had never travelled on a boat like that before."

Just metres from the coast, people had to stop bailing water, giving out to fatigue and at some point as the boat neared Rocky Point the engine had ceased to work altogether.

It was not long after 5am that residents and visitors to the island heard the passengers' screams and yells for help and began efforts to track the boat and contact authorities.

The passengers were mostly without mobile phones, as the captain had advised to throw them, and any GPS systems, away on arrival at Christmas Island.

Only a small number kept their phones and had used them to call emergency numbers. The state's triple-0 call centre logged six calls, including by that made by locals, of which only two calls made it through to police.

Powerless, some of the crew abandoned the ship with what floatation devices they could find as it crashed into the rocks. Passengers were flung into the sea, while others clung to debris.

As life jackets were thrown by locals who braved the dangerous swell on rocky cliffs and rescue boats were launched by nearby navy personnel to the shipwreck, the body count had already begun.

Thirty bodies were retrieved - 11 men, 11 women, two girls, three boys, two female infants and one male infant- and 20 remain missing.

Mr McCusker said the inquiry was one of two that would be held into the tragedy and would focus on what detection and monitoring the nearby navy vessels had, the adequacy of the rescue response and if any improvements could be made, what the intelligence was about the Indonesia vessel setting sail for Australian waters and the whether the island itself had adequate rescue boats and why weren't they able to be used.

Source: brisbanetimes