For these jobs, Mr Adair used support-and-rescue ships and semi-submersible fire-boats all of his own design.

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Built in 2001 by South Korea's Hyundai, the semi-submersible rig is 120m (396ft) long and 78m (256ft) wide, according to Transocean.

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Scarabeo 9 is a semi-submersible drilling vessel recently built by Yantai Raffles, which will be on contract by Repsol YPF for deepwater exploratory drilling off Cuba.

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Its primary business is the ownership and operation of jack-up rigs, tender rigs, semi-submersible rigs and drill ships for operations in shallow, mid- and deepwater areas.

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At the same time, a massive Chinese-built semi-submersible oil rig has been dispatched from Singapore to a position off northwest Cuba, about 50 miles from Key West.

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They are semi-submersible heavy lift ships, which is to say that the ships are designed to be ballasted down so that their main decks go underwater, allowing their cargo to be floated aboard.

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Brooklyn, New York (Motherboard.tv) -- In April of last year the Deepwater Horizon semi-submersible Mobile Offshore Drilling Unit exploded in the Gulf of Mexico, killing 11 men, injuring 17 others and triggering what is generally recognized as one of the greatest human errors ever made and officially the largest unforeseen marine oil catastrophe since people started drilling for oil.

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