It swims!

3 11 2009

Today we got ENDURANCE to float in the melthole free of the crane.

The morning started out with getting the final large chunk of ice out of the melthole. Last night, the Hotsies had been set up to melt a slot cutting off this piece from the bottom of the hole. Finally, the hole is ready for real operations.

Melthole Bottom Lip

Bill taking a picture of the final chunk of ice being pulled out of the melthole. The ice is laced with tracks of bubbles coming up from the underside of the ice.

We finished up bolting on the syntactic and put the final instruments on. ENDURANCE was ready to go in the water.


Bill, Shilpa, Rachel, Vickie and Chris with ENDURANCE all kitted up and ready to go for it's first free swim in the melthole.

However, before it could go off swimming on its own, we had to make sure it wouldn’t sink. Or rather, we needed to adjust its buoyancy just right. If it’s too heavy, it will sink in the event of any kind of power or thruster failure. So you want it to be buoyant. However, if it’s too buoyant, the vertical thrusters will be constantly working to push it down, and it would take a lot of energy (kind of like if you tried to dive underwater while wearing a life vest). So adjusting the buoyancy is a pretty important and delicate step, involving making sure there are no spurious air bubbles trapped inside the ‘bot’s body that might mess up the adjustment, and then carefully adding and removing weights to figure out when it just floats. To complicate things even further, we want ENDURANCE to sit as level as possible in the water, so we also move the weights from side to side and forward and back to take out any listing.
Burping the Bot

Vickie 'burps the 'bot', i.e. rocks it back and forth to get any air trapped underneath to bubble up.

We didn’t get completely finished adjusting the buoyancy. Tomorrow’s plan is to finish that up quickly, and then move on to actually having ENDURANCE do some shakedown missions swimming around and testing out sensors in Lake Bonney.




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