THERE are yachts, there are superyachts and then there is the Felix.

Yesterday she made a reported difficult entry to Airlie Beach's Abell Point Marina where the crew was seen this morning cleaning the deck.

But mystery about who owns the 70 metre ship since she slowly began meandering along the east coast of Australia earlier this year has been rife.

The former research vessel was converted to be the super yacht Amadeus in 2007 for French luxury goods billionaire Bernard Arnault.

It was renamed Felix in early 2016 following its sale to a mystery buyer for an undisclosed price. At the time one valuation put it at being worth 65 million euro ($A100 million).

The 70m ship is configured to take 12 guests in six cabins, plus 18 crew, with facilities such as jacuzzi, gym, cinema, elevator serving three decks and golf driving range.

In 2008 the Power and Motor Yacht website listed it as the 64th largest motor yacht in the world, noting "former British prime minister Tony Blair, his wife Cherie, and rock star Bono cruised together aboard this yacht last summer”.

Speculation abounded that Felix is owned by a North American businessman by social media users when she docked at Port Adelaide in February.

It's not known why she is in the Whitsundays or what other island destinations will be included on her Queensland visit.