Explanation for what caused the rig to blow.

April 30 (Bloomberg) -- A 2-foot-long metal clamp that failed to cut a pipe on the ocean floor may have cost 11 workers aboard the Deepwater Horizon oil rig their lives and cast a sprawling sheet of crude toward fisheries, wildlife sanctuaries and beaches.

All subsea oil wells are equipped with steel blades known as shear rams that are supposed to slash through the pipe at the top of the well during dangerous pressure surges when all other safety devices fail, said Ron Bohuslavicky, the senior well- control instructor at Well Control School in Houston.

The U.S. Coast Guard and BP Plc, which was using a Transocean Ltd. rig to drill the well that erupted on April 20, have been struggling to contain a gusher of crude that has been spewing from the seafloor for more than a week.
A 2002 study commissioned by the U.S. Minerals Management Service, the agency that oversees the offshore oil industry, found that 50 percent of the shear rams tested failed to cut through pipe and halt the flow of oil.
“It’s a bad situation,” said Bohuslavicky, who teaches employees from companies including BP and Transocean how to control blowouts. “The shear ram is the last resort when something like this happens, and if it had done its job then they probably wouldn’t have lost all those people and the rig.”

http://www.bloomberg.com/apps/news?pid=20601072&sid=aKqG43JpQb2w

That's brutal. Especially for your last (only?) line of defense against a blowout.

Sid

You rock corporate America!

This is like saying peoples houses wouldn't burn down if they had fire extinguishers.

The finger pointing and blaming is going to be epic with this spill. With sooooo many many hands in the mix the lawsuits are going to be many.

So anything can and will happen before this is all said and done. The dick takes no prisoner

Grab your popcorn.

the rumor the rig was blown up/sabotaged by "Greenpeace" or some "Liberals" to end drilling. ( I say BULLSHIT) like why would ANYONE risk a disaster like this for political gain? NO ONE is that politically crazed. THAT'S Bullshit... "for Company Profit" is the ONLY cause.

also I read the clamp you describe... or "Fail safe" emergency shut off safety valve was not used because it was not required by law.
Additionally the emergency valve required by other countries costs $500,000 just to install.

Fairly difficult to work at those pressures.

If equipment is not already built and tested at those depths, it is not easy to improvise.

four, count 'em FOUR, safety valves on it, designed to trip when the pressure got to a dangerous level. That's one valve and three backups, not known for failure. It's at the wellhead and if it worked, it would have stopped the gusher. The robot gadgets down there are trying to trip it, but the pressures and mess around the hole are adding to the unknowns.

I found a study back in 2002 that showed shear rams had a failure rate of 50%, and that might still be true. Nobody does much testing of stuff in mile deep water.

on edit...

I guess I found the same study referenced in the article.