The report found the boat was only spotted shortly before it went down Australia has charged three Indonesian men with people smuggling offences, following the death of nearly 50 people in a shipwreck off Christmas Island.
The three men were among up to 100 people on board the flimsy boat when it smashed into rocks on 15 December.
The passengers were mostly Iranian, Iraqi and Kurdish asylum seekers making their way to Australia via Indonesia.
Coastguards rescued 42 survivors but the bodies of at least 18 people have not been found.
The three men – aged 22, 60 and 32 – were charged with “facilitating the bringing to Australia of a group of five or more persons,” police said.
They have appeared in court in Perth and face up to 20 years in prison if convicted, and a fine of up to A$220,000 (£138,000: $219,500) fine.
The three were not required to enter a plea, and the case was adjourned for three weeks.
The lawyer for one of the men said the trio were “unhappy”.
“It’s a total tragedy and they are very upset,” David McKenzie said, according to the West Australian newspaper.
Witnesses said the boat was smashed to pieces on the rocks around Christmas Island last month – witnesses said it went down within and house, leaving survivors struggling to hold on to pieces of wreckage.
It is believed the engine on the vessel failed, while island residents said the seas were the heaviest they had seen in months.
The charges come a day after an official report into the sinking found that the boat – known as SIEV 221 – had only been detected by the authorities shortly before it went down.
The report said the Customs and navy had acted appropriately in carrying out the rescue but recommended that the safety and rescue equipment be increased in the area.
Christmas Island lies in the Indian Ocean about 2,600km (1,600 miles) from the Australian mainland, but only 300km south of Indonesia.
The island is home to a detention centre housing nearly 3,000 asylum seekers who are waiting for their claims to be processed.
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