The decomposing body of a German national was found inside a yacht in Surigao del Sur, Philippines. Courtesy: YouTube/ABS-CBN News. <br />

The decomposing body of a German national was found inside a yacht in Surigao del Sur, Philippines. Courtesy: YouTube/ABS-CBN News. <br />

WARNING: Graphic images.

THE mummified body of a German adventurer has been discovered inside an abandoned yacht.

The grisly discovery came after two fishermen off the coast of the Philippines alerted authorities to a drifting vessel.

The body, found slumped near the boat’s radio telephone, has been identified as 59-year-old Manfred Fritz Bajorat.

Inspector Mark Navales said the cause of death was unclear, but there were no signs of foul play.

“It is still a mystery to us,” said Navales, adding it looked like Bajorat “was sleeping”.

It is yet unclear how long Bajorat had been missing, but sightings of him have not been reported since 2009.

It was unclear how long Bajorat had been dead on the yacht, which was found on Thursday by fishermen in the Philippine Sea about 100 kilometres from Barabo.

Items inside the yacht were scattered, according to Navales, who said the man’s wallet was not found but that the yacht’s radio, GPS and other valuable items were still there.

Local police spokeswoman Goldie Lou Siega in the Philippines said: “We have no evidence of a second person aboard and no weapon was found on the yacht.”

The decomposing body of a German national was found inside a yacht in Surigao del Sur, Philippines. Courtesy: YouTube/ABS-CBN News. <br /> The decomposing body of a German national was found inside a yacht in Surigao del Sur, Philippines. Courtesy: YouTube/ABS-CBN News. <br />

Dr Mark Benecke, a forensic criminologist in the German city of Cologne, told BILD newspaper: “The way he is sitting seems to indicate that death was unexpected, perhaps from a heart attack.”

Officials said dry ocean winds and the salty air helped to preserve his body.

As authorities tried to put together the circumstances of Bajorat’s death, details of his private life have started to emerge, according to The Sun.

He began his travels with his wife in 2008, but the couple subsequently split up. She later died from cancer.

FOUND DEAD PERSON-About 4:00 in the afternoon of February 26, 2016, personnel of Barobo PS received information from... Posted by Barobo Police Station on Friday, February 26, 2016

In 2009 Bajorat is said to have met another sailor, identified only as Dieter, who told BILD that Bajorat was an “experienced sailor.”

“I don’t believe he would have sailed into a storm,” he said. “I believe the mast broke after Manfred was already dead.”

The German embassy in the Philippine capital, Manila, has been notified and is now working on locating Bajorat’s family.

He is believed to have a daughter who works as the captain of a freight vessel.

Here are photos that were taken when Bajorat's boat was found. Photos of the interior of his boat as well as a photo album he had on board. Posted by GHOST of Florida Paranormal Society on Monday, February 29, 2016

— With The Sun.