Meet the cruise liner for ships! Massive carrier craft can hold up to 22 barges - and even an oil rig - on its back

When you need to transport 22 barges – each weighing nearly 3,000 tonnes – half way around the world, you're going to need a pretty sturdy boat.

And they don't get much sturdier than the Blue Marlin, one of the most extraordinary crafts ever to sail the seas.

The incredible ship can carry 75,000 tonnes. Rather than the usual cargo of toys, TVs and coffee, it carries other ships and oil rigs.

When the US Navy needed to give their stricken destroyer USS Cole a lift home, they called on the Blue Marlin.

And when the Australian Navy wanted an aircraft carrier brought from Spain, only the semi-submersible heavy lift ship would do.

The ship of all ships: The largest cargo transport ship in the world, the Blue Marlin of Dockwise, carries four pontoons and 18 hulls on its back from Nantong Port, China

The Blue Marlin's dimensions are eye watering. It is 712 ft long and 138ft deep – and has a deck the size of two football pitches.

It reaches a sedate top speed of 13 knots, powered by a gigantic 17,000 horse power diesel engines, with a crew of 24.

Steering it is said to be like controlling a floating office block.

The barges pictured above – which weigh a total of 60,000 tonnes - were exported from Korea to be completed in Rotterdam.

Some were destined to be river boats, others were off shore construction vessels.

No crane in the world is big enough to lift these sorts of cargoes onto her deck and so she has an ingenious trick up her sleeve.

The deck is submersible and can disappear under 13 metres of water when her ballast tanks are pumped full of water.

Boats, oil rigs and ships can then be floated on before the deck is raised again by emptying its ballast tank.

Carrying an oil rig: The ship set a new record by delivering BP's 59,500tons semi-submersible Thunder Horse platform from Okpo, South Korea to Corpus Christi, USA in 2004

In order to carry the barges, a specially designed set of cradles was added to the Blue Marlin. The barges were stacked up and then floated on the ship a few at a time.

Its biggest cargo was a BP oil rig Thunder Horse 16,000 miles from Korea to the Gulf of Mexico.

The one billion dollar rig is the largest offshore structure in the world and weighed 60,000 tonnes.

Next year the heavy transport ship will take an aircraft carried from Spain to Australian for the the Australian Navy. The aircraft carrier is so large it will overhang the deck by 50 metres.

Less of a load: Two 'Viktor III - Class' nuclear-powered submarines are carried along the coast of Russia

The Blue Marlin carrries another oil rigm this time it is Diamond Offshore's semi-submersible drilling rig, Ocean Monarch. The rig was laoded in Singapore and discharged in Corpus Christi, USA

The Blue Marlin, launched in 1999, is the biggest vessel of its kind. But an even bigger sister is just around the corner.

When finished by the end of the year at its Korean shipyard, the £240 million Dockwise Vanguard will be able to carry 110,000 tonnes.

It has already been booked for its first jobs, including shipping a gigantic oil platform from Korea to the North Sea next year.

Fons van Lith, corporate secretary of Dockwise which owns the Blue Marlin, said there was no shortage of work for the vessel.

He said: 'Safety is the key part of our business. If an oil company invests £1 billion dollars in a piece of equipment that takes two years to build, the one important thing is to get it to the other side of the world in one piece.'