Employing Some Lateral Thinking to Plug the Leak, Using the Dome, But in a Diiferent Way‏

I forwarded the following suggestion to BP as a way of stemming the flow of oil from the Deepwater Horizon laekage 5000 feet below the surface in the Gulf of Mexico:

"I understand that the dome is not working, because of hydrate formation. I don't understand why you have to pipe the leaking oil to the surface in the first place. Why couldn't you just place a heavy object over the leaky pipe? And since you have the dome down there already, and your plan is not working, why don't you just leave the dome there, on top of the leaky pipe, and shut off the valve at the top of the dome where the oil would normally flow through a pipe to the surface? In other words, couldn't the dome just play the role of placing a cap on the leaky pipe, instead of serving as a mechanism for funneling oil for subsequent piping to the surface?"

I now see that NOAA, in its latest update on the response operation, claim that the gas hydrates threatened to lift the dome off of the sea floor. This must be why BP moved the dome off the leak. But, it still begs the question as to why they can't place something heavier over the leaks, to stop them from flowing. Why couldn't they lower a tank barge, for instance, or even a rail car or locomotive? Presumably objects such as these would be large enough to withstand the pressure from the rising, leaking oil, and not get blown off the site.