The world's LARGEST sailing boat revealed: Russian billionaire's £260m superyacht is 300ft high, has eight floors and an underwater observation room

• At 468ft in length, with ship masts nearing 300ft high, Superyacht 'A' is the world's biggest sailing ship
• The yacht has been built for Russian billionaire Andrey Igorevich Melnichenko out of a German shipyard
• Cruise speed is 18mph, with a top speed of 24mph. The hull is made of steel, with a teak-finish deck
• Superyacht expert tells MailOnline that it will be 'very significant ship' once the interior work is completed

By John Hutchinson for MailOnline

Published: 11:19 GMT, 21 September 2015 | Updated: 12:21 GMT, 21 September 2015

This luxury yacht is the definition of 'mega.' 

Built for Russian billionaire Andrey Igorevich Melnichenko, superyacht 'A,' the 'White Pearl' is taking its test voyage in Kiel, northern Germany.

The ship is believed to have cost almost £260million and is the world's largest sailing superyacht.

The luxury yacht, that was built at a shipbuilding yard near Hamburg, Germany, has masts that are 300ft high

At 468ft in length, with ship masts nearing 300ft high, the 'mega-yacht,' has eight floors and includes an underwater observation room.

Superyachtfan.com reports that the boat is powered by a 'hybrid diesel-electric package with controllable pitch propellers,' and is designed to accommodate 20 guests and a crew of 54.

Matrix Lloyd, the global authority on Superyachts, told MailOnline Travel that while the ship may be ready to sail, the interior design work will be ongoing.

'While she's been launched, the interior will take many more months to complete,' said Lloyd.

'It's where the cash really gets splashed. Interiors typically cost at least £10,000 per square metre – and often much more.

'Make no mistake - this will be a very significant ship. While precise details of the sailing rig have yet to be released, not since the days of the mighty clipper sailing ships, such as the Cutty Sark, has such a large sailing vessel been built. 

'This new superyacht will be nearly twice the length and over twice the width of the Cutty Sark. She will instantly become an inspiration to cargo ship owners, and a floating demonstration that sails - combined with the latest materials and technology - mean that dirty diesel engines are no longer needed as the primary means of propulsion. 

'The green lobby should be celebrating - as cargo ships are significant CO2 contributors.

'The masts were built by Magma Structures in Portsmouth - just a stone's throw from another well known sailing vessel, HMS Victory, which is less than half the length of this new superyacht.' 

Boat International reports that the previous argest sailing yacht on the water is 96.35 metre Sea Cloud, a classic beauty launched in 1931, followed by the modern falcon-rigged iconic yacht Maltese Falcon at 88 metres LOA. Sailing Yacht A will handily surpass both of these.

Helipads, hot tubs and en-suite staterooms: Inside the most expensive superyachts for sale at the Monaco Yacht Show where asking prices reach £51MILLION

Walk-in wardrobes, opulent en-suite staterooms, outdoor hot tubs, helipads - and even lifts that transport guests between decks.

These are some of the eye-catching luxury facilities on board the superyachts that will be on display at the Monaco Yacht Show. More than 120 of the priciest private vessels in the world will be on show over four days at historic Port Hercule, starting on September 23.

The 25th edition of the event in glamorous Monaco brings together manufacturers, owners, buyers and enthusiasts at what is considered the most prestigious pleasure boat show in the world.

With more than 33,000 people expected to attend, these are some of the most expensive vessels for sale, according to MatrixLloyd, a leading authority on superyacht deals.

Source: Daily Mail, UK.