Posted on 10/21/2003 4:15:50 PM PDT by NormsRevenge
WASHINGTON (Reuters) - Methane bubbles from the sea floor could, in theory, sink ships and may explain the odd disappearances of some vessels, Australian researchers reported on Tuesday.
The huge bubbles can erupt from undersea deposits of solid methane, known as gas hydrates. An odorless gas found in swamps and mines, methane becomes solid under the enormous pressures found on deep sea floors.
The ice-like methane deposits can break off and become gaseous as they rise, creating bubbles at the surface.
David May and Joseph Monaghan of Monash University in Australia said they had demonstrated how a giant bubble from one of these deposits could swamp a ship.
"Sonar surveys of the ocean floor in the North Sea (between Britain and continental Europe) have revealed large quantities of methane hydrates and eruption sites," May and Monaghan wrote in their report, published in the American Journal of Physics.
"A recent survey revealed the presence of a sunken vessel within the center of one particularly large eruption site, now known as the Witches Hole."
"One proposed sinking mechanism attributes the vessel's loss of buoyancy to bubbles of methane gas released from an erupting underwater hydrate," they wrote." The known abundance of gas hydrates in the North Sea, coupled with the vessel's final resting position and its location in the Witches Hole, all support a gas bubble theory."
No one has ever seen such an eruption and no one knows how large the bubbles coming off a methane deposit would be.
May and Monaghan created a model of a single large bubble coming up under a ship. They trapped water between vertical glass plates, launched gas bubbles from the bottom and used a video camera to record what happened to an acrylic "hull" floating on the surface.
"Whether or not the ship will sink depends on its position relative to the bubble. If it is far enough from the bubble, it is safe," they wrote.
"If it is exactly above the bubble, it also is safe, because at a stagnation point of the flow the boat is not carried into the trough. The danger position is between the bubble's stagnation point and the edge of the mound where the trough formed," they concluded. ).
That is if the crew can breathe methane. More than likely the crew would die and the ship would survive.
|
And their statements about no one ever witnessing the effect are also wrong. There are several recorded incidents (including film footage) of floating drilling platforms that have struck methane hydrate layers and released bubble storms that have sunk the rigs like there was nothing under them to bouy them up (which, in effect, was true).
The other thing they don't mention about methane bubbles is that they're explosive. Ships encountering these bubble fields lose bouyancy. Any ignition source and the whole shebang goes bang!
Methane hydrate deposits could be a fantastic source of energy, but the risks involved in extracting it are huge. Of course, the risks involved in NOT extracting it (safely) are also huge. Lot's of big areas in the world are literally sitting on top of big fuel/air bombs. Wouldn't it be lovely to find deposits of this stuff at strategic locations and design a weapon to liberate it when we want and then provide an ignition source? Wouldn't it be a pain if someone else figured this out first?
My God! There's a methane hydrate gap!
Next, they are going to research if there are any good alternatives to the 8 track player.
A trawler found at the bottom of the North Sea may have been sunk by a massive and very sudden release of methane gas, scientists speculated on Wednesday.
http://news.bbc.co.uk/1/hi/sci/tech/1047249.stm
I need to get myself out of this work grind I've been in for the last 25 years and get me a "research grant" - several of them in fact.
I've got some great ideas that need serious series study....
- Why the sun always rises in the east and sets in the west.
- Why Lil Tommy D. is always "deeply saddened or concerned."
- Why Hollyweird celebs are such raving idiots, and insist on proving that fact over and over and over again.
Wow, lots of possibilities when ya get into the Lib / Rat arena.
LVM
We know for sure that there are deposits of natural gas in the earth. In theory, natural erosion might eventually allow one to escape on its own. However, it's not at all clear why this would happen on the bottom of the ocean, an environment more favorable to deposition than erosion.
At any rate, if I understand the article, methane is laying around already exposed on the sea floor in semi-stable hydrate form, just waiting for some odd event to turn it into a huge gas bubble. If that's true, there's more untapped energy out there than we thought. The problem is that someone should have put the whole business on a more solid observational basis by this late date than seems to be the case.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.