Karen's Daily Blog

During a quiet afternoon while Alvin was diving at the Guaymas Basin and the samples from the night before had been processed and stored, engineers from the Deep Submergence Group filled us in on the work being done to create new submersibles at WHOI. 

The Woods Hole Oceanographic Institution keeps coming up with cool new things to sink to the bottom of the sea, making them seem like a cross between mad scientists and Santa’s elves. Jonathan Howland showed us the menu that includes Remote-Operated Vehicles (ROVs) such as Jason II, and Autonomous Underwater Vehicles (AUVs) like ABE.   Daniel Gomez-Ibanez told us about a hybrid ROV, Nereus, which can dive to 11,000 meters – the deepest point in the ocean, as well as destinations under ice. And Lane Abrams filled us in on the progress of the sub that will eventually be housed and tended by Atlantis. 

This engineering drawing shows the preliminary design of the replacement submersible.

WHAT?!  Is Alvin being sent out to pasture? There once was a plan and design to build a new submersible, but it has now been scaled back to a “phased approach,” meaning that they will retrofit our existing Alvin, reusing some of it and adding a new pressure hull, new batteries and fiber cable to replace much of the copper wiring.  

The personnel sphere has already been forged from two 17,000-pound ingots of titanium.  (Take a look at the great pictures we got from WHOI.) First it was flattened into pancakes, then forged into two hemispheres.  They are being rough-machined now, and in the new year they will be welded together to form a sphere 89 inches in diameter, 4 ½ inches larger on the inside than the sphere Bruce Expedition Leader and Chief Pilot Strickrott, Pilot-in-Training Korey Verhein, Eric Wommack, Pilot-in-Training Korey Verhein, and Eric Wommack, are diving in today. “It doesn’t sound like much,” Lane says, “but that is almost 20 percent more volume.” The final sphere will have walls 2 3/4 inches thick; when forged the hemisphere walls were six inches thick – so that gives you an idea of the machining process.

The larger two titanium ingots shown here were forged into the two hemispheres that will become the replacement sub’s personnel sphere. The smaller ingot will be divided up to make additional titanium parts for the new sub, such as components of the hatch and the viewports (windows).

 

Next year attachments are made to the sphere and 16 penetrators (conduits for cables) and five porthole windows will be installed. The Alvin upgrade will have windows larger than Alvin’s that are positioned differently, to allow better access and fewer blind spots. 

Syntactic foam will likely not be upgraded yet, so the sub will be limited to 4,500 meters of depth in the first phase, matching Alvin’s present maximum. Eventually new flotation material will be developed for the sub to give it  the ability to withstand the pressure needed to dive 6,500 meters, giving divers access to about 97 percent of the ocean floor. The titanium sphere will soon be ready to deal with the 10,000 pounds of pressure per square inch (psi) imposed on it at the replacement sub’s maximum depth, 650 times the pressure at the sea surface. (In comparison, the pressure on the sea floor at 9º North is 250 atmospheres.)

And what will become of the batcave? “Our goal is to be smarter with power,” says Lane. That means out with the lead acid batteries now in use, in with lithium batteries. “They’ll give the new submersible two-and-a-half times the energy it has now.”  What will the sub do with the extra energy? The increased battery power will allow the sub to work for 8 to 10 hours on the ocean floor at the depths we’re exploring today – 2,000 to 2,500 meters – and will provide the extra hours needed to descend to greater depths. 

A disk of titanium flat as a pancake is heated, and a die is pressed into it to create a hemisphere. A high-energy electron beam will be used to weld the two hemispheres together. ( photo courtesy of Advanced Imaging & Visualization Laboratory, Woods Hole Oceanographic Institution)

Lee Stanish asks Lane, “Why did they decide to stop at 6,500 meters?” In other words, what is that other three percent of the seafloor, chopped liver?  Lane suggests that the amount of seafloor that is deeper than 6,500 m is small enough to make it a situation of “diminishing returns,” meaning that the effort to go the extra mile (or miles, in the case of the Mariana Trench) didn’t make the extraordinary effort and money it would take to create a manned submersible capable of those depths worthwhile.

No, the Mariana Trench is not chopped liver.  The Deep Submergence Laboratory at Woods Hole Oceanographic Institution does have a new vehicle headed down there.  Nereus, a remotely operated vehicle that was tested last November by its engineers – including Dan Gomez-Ibanez, who is working with the Alvin group aboard Atlantis, will make its first dive to the world’s deepest trench, in the Pacific Ocean near Guam, in spring 2009.

Today's Extreme Blogger:
Julie Smith

Basket Cases

T: Julie Smith, Lee Stanish, and Karen Lloyd are our resident “basket cases.”

As the sun sets and samples are carted off to shipboard labs for processing, our basket pit crew moves into position. Lovingly called the “basket cases”, we prepare the sampling equipment on the sub for the next day’s dive. It is a dirty and wet job, but we are thrilled to do it. Salt water must be washed out of the mechanical parts of the Sipper, hose clamps loosened and tightened again, and the almost icy water from the ocean floor needs to be siphoned out of the Bioboxes by holding a tube in the bottom with hands that slowly go numb. The skin on our hands gets waterlogged and wrinkled. Fingers and palms get scratched as Alvin sometimes “bites”. Clothing and shoes get wet and muddy or stained with rust. Maybe this doesn’t sound fun to you, but for me it is one of the best parts of the day. There is just something sublimely satisfying about doing manual labor on the ship. I proudly wear my cuts and dirty fingernails as tiny badges of honor and revel in just how dirty I can get. It makes me feel like a five-year-old again. This is nothing like my usual role in a microbiology lab when I am very conscious of my sterile technique. That must be why I like it so much.

And I am not alone, I have a loyal team that helps with the work. There is usually music in the hangar, thanks to satellite radio and the amazing collection of albums owned by the Alvin pilot-in-training, Anton. The hangar is open to the warm sea breezes and the sound of waves lapping against the ship. The atmosphere and companionship are hard to beat.

Even though I don’t have my own project on this cruise, the samples that are collected with the equipment that I am preparing are crucial for the other scientists onboard. If samples are lost or contaminated due to equipment failure, a lot of precious dive time and effort are wasted. That is a heavy burden and the night before our very first dive, I could hardly sleep. Luckily, my worry was for naught and the dive was very successful. Problems do occur at times and we learn from our mistakes. We modify equipment as needed and we bring plenty of spare parts for repairs.

At the end of the night when the basket on the front of the sub is finally set back in order, ready for the next day’s collections, I head back along the starboard side of the ship. Invariably my eye is drawn to the water where a spotlight shines down. The light draws fish and squid to the surface. The orange squid are my favorite, with their characteristic propulsion through the deep turquoise water. Finally, I bid goodnight to the ocean and head in to get cleaned. It is a dirty job, but somebody’s got to do it, and I am more than willing.

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