The Cave of Wonders

You will wish you were here! Day two of the cave had a few exciting discoveries... as well as a couple of newly created set-backs. Because our sonar was out of commission the first visit, we spent all of Thursday repairing and splicing the tether that caused the problem. Today, we finally had a chance to map the cave and the wonders contained within its depths.

The newly repaired tether worked like a charm as we mapped the surface of the first pool in the cave. We also mapped varying depths at multiple locations in the cave that we hope to "paste" together. This will hopefully be enough data to completely represent the water within the pool in the cave. In addition to horizontal scans with the sonar, we ran a couple of lengths in the pool with the sonar strapped vertically to the ROV. This will provide us with two sets of dimensions to log the depth of the pool. We used this method primarily to make up for our faulty depth sensor in the ROV's control box.

After mapping the pool, I drove the ROV around to get some close up video of the sides and bottom of the pool. I found a lot of interesting things... a couple of tires and oil bins, plenty of rubble, bottles, and occasional sections of wood. One particular piece of wood had a community of water creatures... either miniature crawdads or a type of shrimp. It was pretty cool!

Unfortunately, our repaired cable suddenly failed and we lost driving ability for the robot. We switched to our other tether, but that one didn't connect sonar, so we only did visualizations from then on.

All in all, the cave was very exciting. I only wish I had my scuba gear to dive down in it!

(More?) Hardware Repair

So we decided to stay home on Thursday (March 10th) after running into some hardware troubles on Wednesday and ended up getting a lot of troubleshooting done. Our major goals for the day were making the partial ROV water-proof so that we could check its depth sensor in our makeshift pool (a large trashcan), checking the depth sensor of the full ROV, and doing some work on one of our tethers so that we could get full communication with the ROV (one of the problems we experienced Wednesday).

Tyler and I worked with the ROV and Brig and Jeff took on the tether job. We hoped to meet up later in the day to connect the 2 hopefully-fixed pieces of hardware. Tyler and I put the trashcan into the shower and filled it up with water.

We waterproofed the partial ROV and put it in the water for the first time since we've been here in Malta (we had been primarily using it for parts). We used both ROVs and both of our control boxes to test the depth sensors. We received inconsistent readings of depth on the control boxes, and could not communicate with the sonar unit at all. After some testing, we took a break and got some McDonald's coffee down the road. We were even graced by Timmy's presence midway through our day.

Jeff came down and finished up splicing the new piece of the tether together so that we could combine our jobs from the day.

The fixed tether solved the sonar communication problem completely! We now knew that the problem was in the other tether (the one not spliced) so we could now actually get sonar data from the cave! We also tested both cables connected in tandem so that we might be able to get some extra length in the huge cave. The cables connected and were able to control the ROV, but we still did not have sonar communication, which again assured us that the error was within the tether.

The final step was to waterproof the new connection. This required wrapping each connection in electrical tape to prevent shorts, sealing all the connections with epoxy, heat shrinking the epoxy, covering this in a sturdy hose-like wrap, and finally epoxying the ends of the cover.

By the end of the day, the ROVs were back together and waterproofed, and the tether could now communicate with the sonar. Although we lost a day at the cave, we were able to successfully remedy some major problems, and the entire team felt like it was a good choice.