UPDATE 3-Oil firms to store crude on ships as oil tanks

* Koch, Shell hire supertankers for storage

* Higher future prices encourage companies to store

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By Luke Pachymuthu

DUBAI, Nov 20 (Reuters) - Oil companies plan to store millions of barrels of crude at sea as they wait for demand to pick up and prices to rise.

So far oil companies have booked ships capable of holding up to 10 million barrels, brokers have said, more than the daily output of top exporter Saudi Arabia.

On Thursday U.S. oil trader Koch and Royal Dutch Shell (RDSa.L) were the latest to confirm bookings of additional Very Large Crude Carriers (VLCC), brokers said.

The companies were not immediately available for comment.

Brokers said the cost of hiring vessels at current depressed rates would be less than the gains from waiting for an upturn in crude prices and in refiners' profit margins.

More oil and trading firms were also considering floating storage, they said.

"If you're looking at it from a cost perspective, just float the oil. The way to make money is to buy long and then go short," one trader said.

U.S. crude CLc1 has fallen more than $90 from its July peak above $147 a barrel as the slowing economy hurts global oil demand.

Some of the vessels were to load crude in the North Sea, the first time large volumes have been placed in floating storage there since the oil price crashed to below $10 a barrel in 1998.

"All this oil has to go somewhere, especially if the refiners aren't running at capacity," a Singapore-based crude oil trader said.

Koch has booked VLCC the Dubai Titan, with capacity to hold over two million barrels, for storage off the U.S. Gulf Coast. They added that Koch had already taken two other VLCCs for storage in the U.S. Gulf.