Boat sunk by explosion retrieved from watery grave off Auckland's Herald Island

A photo of the boat taken hours before the explosion. Photo / File

The yacht that exploded and sank off Auckland's Herald Island has been hauled back up - without the owner's knowledge.

"I haven't heard that," Mike Lawler said, when the Herald told him of the salvage of the wreck of his kauri boat.

Authorities had not asked him for the cost of about $12,000 for the job - and he didn't have the money to pay.

The explosion - believed to have been caused by an LPG leak - tore through his boat with a force that residents likened to a "sonic boom" on July 29.

He said he had recovered from burns he suffered in the explosion but was suffering ongoing problems with an injured leg.

A roofer by trade, Lawler is a devoted boatie who previously told the Herald he was shocked by what had unfolded and was not insured for such a catastrophe.

Auckland Transport harbourmaster Captain Andrew Hayton said boat owners were expected to arrange for the disposal of any wrecks themselves.

"It's their property and the expectation is that they will do the right thing," he said.

"Unless it's a navigational hazard we don't rush in with all guns blazing.

"Unfortunately, we are finding more and more owners aren't doing the right thing and are reneging on their responsibilities," he said.

The age of the boats moored around the region was on the climb exacerbating the problem as they fell into disrepair and sank, often while still stationed at their moorings, he explained.

They were probably looking at a sum of about $12,000 to cover yesterday's removal work, he said.

The boat was lifted by crane after divers secured the necessary strops. Photo / Supplied

Just months prior they had also footed the bill for the retrieval of a heavy ferro-cement yacht that sank off Hobson Bay which cost just short of $30,000.

"The problem is getting worse, it's not getting any better," Hayton said.

It was becoming "increasingly untenable".

"So we are looking at perhaps reviewing the mooring fees that these owners pay so we can recover some of those costs."

An onlooker, who did not wish to be named, praised the "skilful" manoeuvring that began about an hour before the incoming full tide.

The wreck was pulled from the water yesterday. Photo / Supplied

Two divers entered the water to place two large strops in around the sunken wreck, before it was lifted by a crane, he said.

It appeared to be a difficult removal as the sunken vessel was still attached to the mooring, he said.

While an awkward job it was well undertaken and "a credit to all the people involved".