While it is rumoured among treasure hunters that some officials are not adverse to cutting individual deals, the searchers also eye each other with mistrust.

'Eighty percent are scoundrels and mountebanks,' Keppler says.

Apart from the revenue, Indonesia's interest is limited, as is obvious with the second wreck Keppler found in a depth of 50 metres off Java island, says Horst Liebner, an expert on Malay culture and history.

'The Karawang wreck is from the 10th century,' Liebner says. 'In Germany, such a find would be a sensation, but in Indonesia, not a single archaeologist stopped by to have a look.

Liebner dated the wreck with the help of Chinese lead coins from the Min dynasty, which fell in 947. Divers also recovered vases, ewers and plates.

'It's a time capsule,' he enthuses.

So far, the treasure hunters have not become rich. The flotilla of salvage ships, equipment, divers and storage all needed to be financed in advance, long before any promising finds were on the horizon.

Therefore, investors attracted by a sense of adventure are welcome.

But occasionally there is a wreck that fulfills the treasure hunter's hopes. 'We checked out about 70 wrecks here, but only five of them are probably worth it,' Keppler says.

The money only starts coming in when a buyer is found. Keppler's team is in negotiations with Chinese museums over the Karawang treasure, which he hopes will bring in 1.4 million euros ($2 million) with salvage costs amounting to 600,000 euros.

The Forbes might prove more profitable, netting 5 million to 10 million euros, with 400,000 euros in salvage costs.

'There are more than 30 million coin collectors worldwide,' says Keppler, who admits to be more fond of modern currency himself.

But in the end, he is in it for the search -- his eyes already set on future wrecks to be discovered.