Buoyancy: A Real-World Example

Doug Levin is the Associate Director for the Center for
Environment and Society at Washington College in Chestertown, Maryland,
and is an expert in underwater exploration technology, as well as
designing fun programs that teach complex engineering concepts.

Answer to last post’s thought question: How are submarines similar to drogues?

A surfaced submarine is positively buoyant. A diving submarine is negatively buoyant. A submarine staying still in the water column is neutrally buoyant. 

Below: Doug works on “Echo,” helping to get it back in the water after the tether was cut by the boat propeller.  The yellow parts of this device were made of dense, buoyant foam.

Doug_Post1_echo.jpgRemotely Operated Vehicles (ROVs) are devices used to explore the ocean. You might have seen them on TV a couple summers ago during the BP oil spill disaster taking video of the oil coming out of the broken pipe a mile deep in the Gulf of Mexico.  ROVs can cost several million dollars. On occasion, they get tangled in things that lie on the bottom of the ocean, lose power, or suffer cut cables. Losing ROVs in any of these ways is not a pleasant experience. 

While I was working in the Black Sea, the tow cable that connected us to our ROV was severed by our ship’s propeller.  There were a lot of nervous nellies on board that began scanning the water surface for our bright yellow device named “Echo.”  I went to the galley, got a cup of coffee, and went up to the boat bridge. This was the highest vantage point to keep an eye on the water surface. About twenty minutes later, “Echo” was spotted at the sea surface.  We retrieved her, spliced the tether back together, and re-launched her, continuing our operation.

Thought question: How would you design an ROV that had a good chance of being found if it failed completely?

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Gulf of Mexico’s Oil Spill Impact Intrigues Geographers

It has been more than a month since the April 20th Deepwater Horizon drilling rig exploded in the Gulf of Mexico, leading to an oil spill that, according to the Guardian, has already dumped 42-100 million gallons of oil into the Gulf of Mexico.  Since then, the news has been filled with stories about skimming, tubes, domes, Top-Kill, cut and cap plans, and economic and environmental degradation. 


Courtesy Cheryl Gerber

Public beaches were closed Friday in Grand Isle, La., as oil, dead fish, and birds washed ashore.





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The massive impact of this disaster is difficult to wrap our minds around, and yet it is increasingly important that we try to do so.  This disaster is not an abstract story in the news.  It is a tragic misfortune that affects people, economic chains, ecosystems, and the planet.  Most importantly, it is preventable. 

In permit applications to drill in the Gulf, BP said that it was, “prepared to handle an oil spill more than ten times larger than the one now spewing crude,” according to reports from Alison Fitzgerald of Bloomberg News.  Bob Deans, spokesman for the Natural Resources Defense Council in Washington, categorized BP’s actions as, “overpromised and underdelivered.  They told us they had a plan that could deal with the consequences of a worst-case scenario. They don’t.”

Even though the worst case scenario detailed in BP’s disaster plan was far worse than the Deepwater Horizon spill, this spill is a worst case scenario for the local economy and environment.

The Oil Spill and the Economy

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