A sophisticated search vessel tasked with tracking down Malaysia Airlines flight 370 disappeared mysteriously after turning off its tracking system, sparking conspiracy theories.

The Seabed Constructor's Automatic Identification System (AIS) went offline on January 31 - just ten days into its search.

Bizarrely, it reconnected last night after 80 hours of undocumented travel. The reason for this temporary disconnect remains unclear.

The Seabed Constructor (pictured) left the Port of Durban on January 2 and began searching for Malaysia Airlines flight 370

The Constructor left the Port of Durban on January 2 and began searching for the plane, which vanished en route to Beijing from Kuala Lumpur on March 8 2014 with 239 people on board.

The plane vanished after its aircraft communications, addressing and reporting system (Acars) was switched off less than an hour after taking off.

The vessel had been contracted on a 'no find, no fee' deal by Texan exploration company Ocean Infinity.

It planned to use sonar scanning equipment to find the aircraft, after a multinational search cost Australian, Malaysian and Chinese $200million.

Working for the Malaysian Government, the US company was offered more than $55million if it found the plane within 90 days, told Fox News.

The freelance boat's designated search area was located just outside the 120 square kilometres previously scoured along the 7th Arc - the zone aviation specialists say is most likely to be where MH370's fuel reserves were exhausted.

No sign of the plane was found and an Australian-led hunt - the largest in aviation history - was called off in January last year.

The vessel was tasked with searching the zone aviation specialists say is most likely to be where MH370's fuel reserves were exhausted, dubbed the 7th Arc

The Australian Transport Safety Bureau (ATSB) attempted to find missing aircraft MH370 for two years. A private company has renewed its pledged to locate the wreckage on a 'no find, no fee' basis

Malaysia Airlines flight 370 (pictured) vanished en route to Beijing from Kuala Lumpur on March 8 2014 with 239 people on board.

The plane vanished after its aircraft communications, addressing and reporting system (Acars) was switched off less than an hour after taking off

The Constructor is not the first to comb over this patch of ocean.

Fugro Equator, Fugro Discovery and Havila Harmony have all attempted to find the presumably downed plane.

Only three confirmed fragments of MH370 have been found, all of them on western Indian Ocean shores, including a two-metre wing part known as a flaperon.

Each ship's progress was tracked meticulously by aviation enthusiasts and conspiracy theorists.

Keeping tabs on the Constructor has proved more challenging: the vessel went dark on Wednesday, causing massive speculation.

One online user speculated the vessel it had found MH370 but planned to keep its location secret until it had confirmed its government-funded fee.

Another speculated Ocean Infinity had failed to find the missing Boeing 777 and had instead detoured towards the wreckage of what is believed to be the S.V Inca - a Peruvian transport ship that vanished on the way to Sydney more than 100 years ago.

Four kilometers inside the 7th Arc, the century-old ship was spotted by one of the Constructor's predecessors, the Havila Harmony, which mistook the shipwreck for the lost plane's fuselage.

A multinational search cost Australian, Malaysian and Chinese taxpayers $200million. This piece of aircraft debris discovered on the island of Pemba, off the coast of Tanzania

MH370 was tracked by amateur aviation enthusiasts and conspiracy theorists alike

Inevitably, on its discovery there were chatters about lost treasure and Inca gold.

The Constructor's involvement in this new chapter in the aircraft's bizarre disappearance has not be to everyone's liking.

Aviation journalist Jeff Wise was critical of the new search in his blog.

As a former member of the independent group of investigators tasked with advising the Australian Transport Safety Bureau in its search for MH370, Wise is personally invested in the case.

'As I write this, the scan of the innermost section of the Primary Search Area has been completed, but the assessment has not yet been released.

'However, the fact that Seabed Constructor has moved on to another area suggests that probably nothing was found there, either.

'A big caveat: we don't really know how long it takes the search team to assess the data collected during each pass.

When the Constructor turned its AIS back on last night it was heading for Perth where it is scheduled to dock at Fremantle on February 8.

With little to no information coming from the ship, it remains unclear what, if anything, it has found.

Seabed Constructor is expected to dock in Freemantle to refuel and top up supplies before returning to the search area.