The search for the lost Malaysian Airline jet MH370 has been renewed, and the search vessel started towards the crash zone as of Thursday.

Bloomberg reports the GO Phoenix, a Malaysian-contracted boat, left Singapore Tuesday and will receive search zone instructions soon, according to Martin Dolan, Australian Transport Safety Bureau (ATSB) chief commissioner.

The Malaysia jet, which disappeared from radars on March 8 while en route from Kuala Lumpur to Beijing with 239 people on board, has not been found despite an international effort following the disappearance.

The deep-sea sonar search by GO Phoenix will cover an area of 23,000 square miles off the coast of Perth, in Western Australia.

"We're now at the point where we can say we've pretty much got a sequence of priority areas along the arc," Dolan said told Bloomberg. "We know the first place we'll be searching and we'll be formalizing the tasking for that within the next few days."

The last major effort ended in May when Australian search crews reported hearing sounds that may have been the black box, but nothing was ever found.

Since then, in the past four months, survey vessels have been mapping the surface of the ocean floor, to include ridges, trenches, undersea mountains, and featureless plains to help guide the deep-sea search, Bloomberg reports.

"We can see extinct volcanoes, 2,000-meter cliffs," Dolan said."We've had really good vessels and equipment, and highly skilled crew. If all that comes together I'm cautiously optimistic."

The Malaysian government requested the search be headed by Australia.

"The complexities surrounding the search cannot be understated. It involves vast areas of the Indian Ocean with only limited known data and aircraft flight information. While it is impossible to determine with certainty where the aircraft may have entered the water, all the available data and analysis indicates a highly probable search area close to a long but narrow arc of the southern Indian Ocean," The ATSB said in a statement.