Month: February 2014

                During the last two weeks of the Wave Chaser’s cruise in the Samoan Passage, problems grew exponentially for the marine techs.  The tow-yo troubles continue; and as we work the winch harder and harder, it shows more and more signs of exhaustion.  A bearing broke in one of the sheaves that guide the wire onto the spool as we’re pulling it up.  This caused the sheave to wiggle and resulted in a heavy metal cable with thousands of pounds of tension on it to overlap on the spool.  (The cable usually wraps in perfectly even rows to avoid uneven loads or snapping under high tension.) It also has delicate electrical wire inside of it, which can break if stretched or twisted too much.  These are all big problems, but the sheave replacement was not a marine tech problem.  The engineers handled the replacement of the bearings in this sheave and they even let me help!

                Towards the very end of the cruise, while all of our attention was focused on the reoccurring winch problems, yet another challenge presented itself.  The Internet went down and the pressure was on to fix it!  We keep an oscilloscope hooked up to the antenna which tells us if we are transmitting and receiving satellite signal.  The signal disappears whenever the ship rolls a certain way.  My marine tech advisors, Brandi and Jason, explained to me that this is usually due to the mast getting in the way of the satellite dish, which is almost directly below it.  So we waited until the next time the ship changed its heading. Once we turned, we hoped that the mast would no longer be between the satellite and our satellite dish.

No luck.

                The next day we went up into the dome!  The dome is a large, weatherproof, fiberglass container where the satellite dish lives.  It has an air conditioner to keep the electronics cool, which was nice on a hot afternoon, but it is not easy to walk around inside of it.  Once you climb up inside of it there is only a narrow pathway to walk around while having to duck to avoid hitting the gimbal mount.

                Our first plan of attack was the classic question—“Have you tried restarting it?” But once again, we had no luck. Upon further investigation and e-mailing, though, we came to the conclusion that the problem was that it was having trouble pointing towards the satellite.  (We have an extremely small spare satellite Internet dish for emergencies like this.  However, it has a very small bandwidth.)

On a ship nothing stays still, and with this satellite dish we need to point it directly at its satellite.  So, the perfectly balanced gimbal compensates for the pitch, roll, and yah movements of the ship and it also has motors to adjust where in the sky the dish is pointing as we cruise across the ocean.  So, we figured out where it needed to point and told the motors to point it in that direction; however, it couldn’t do what we told it to do.  This is indicative of a mechanical problem.  So we investigated up in the dome again. 

We turned on the gimbal motors while we were inside of the dome.  This was scary.  The satellite is very big and takes up the upper half of the dome, except now it was tilted all the way down and pointing at the horizon.  So, we were squished on the other side of the dome with nowhere to walk.  Then the satellite went into “searching mode” and started chasing us around in circles inside the dome.  It was quite the thrill.  We eventually realized that the satellite is actually above us and the dish is not pointing upward.  We concluded that the motor that turns the satellite from the horizontal position to the upright position wasn’t working.  (Think of the act of tipping over a birdbath and picking it back up.) Luckily, we did have a replacement for it onboard!  So Jason and I went up into the dome for a few hours and swapped out the motors very delicately.  Once we turned the dish back on, we check our e-mails and there was much rejoicing!

The combination of the failing winch, losing an instrument, and the Internet being down is a perfect encapsulation of the uniquely challenging job of being a marine technician.  These problems could cause a panic, but it is our job keep calm and make the smartest use of the shipboard resources we have and get as much data as possible for the scientists.  Every day there is a new, difficult, and exciting project to tackle; and I couldn’t ask for a more intellectually stimulating experience!

We’ve hit the midway point in the Wave Chasing cruise! Up until this past week, almost everything has gone according to plan.  So, it was about time that a challenge presented itself, and what a challenge it has been!

The art of the tow-yo is simple enough to understand.  The goal is to be able to look at the ocean in two dimensions, basically a side view map of the temperature and salinity differences.  In order to get a continuous cross section of data, we must raise and lower the CTD sensors like a big yo-yo (hence the name) while the ship is moving slowly forward.  We do this for as much as 27 hours straight!  Now the challenge arises when you figure the amount of stress that puts on the winch, the scientists and the winch operator.    

The CTD is a half-ton jungle gym crawling with electronics and expensive sensors, and it hangs miles below the ship by a single cable that is not even as wide as my pinky.  It is so far away that if it were to look up at us, we would be look much higher than most skydiving planes ever go.  Not only is it really far away, it is also in a harsh dark alien world, under bone-crushing pressures and surrounded by a concoction of salts that is constantly trying to corrode and short-circuit our conductors.  It is not the easiest place to send our heavy jungle gym of expensive electronic equipment.

So, the story starts out with a seamount creeping up on us while we have the CTD close to the bottom.  It accidentally hit this seamount and may have even tumbled a little bit.  After bringing it back on board to be inspected, we found seafloor sediment and a few broken sensors.  Then we discovered some kinks in the wire and had to cut off about 250 meters of this 10,000 meter cable. It took six hours until the sensors were replaced and the cable was ready to go back in the water, but that wasn’t the end of our problems. 

After we fixed everything that looked wrong with it, we put it back in the water and sent it back down to five kilometers under the sea surface.  But it only made it to ~3 kilometers before something short-circuited and shut off some of the equipment. Then we had to bring it back up for more repairs!  

This time it was evident to my supervisors that the problem was that there was water getting into the wire somewhere and the most likely place is a soldered connection between the 10km wire and rest of the electronics on the CTD. 

In order to fix this new problem we had to redo the waterproof splicing which we did using the hot glue method.  This proved to be successful and we had 14 blissful error-free hours of CTDing, but then the real trouble started!

In the middle of the night, the display that shows the pounds of tension on the cable started skyrocketing!  We immediately panicked, because the only reason that the tension would have spiked is if we had snagged something on the bottom of the ocean. Straightaway, all chiefs, techs and captain reported to the bridge to discuss what to do next.  The tension normally never goes over 4,000 lbs. and the breaking point on the cable is ~10,000 lbs.  At the time it was showing ~9,000 lbs.!  We stopped the ship instantly, because if cable breaks the CTD plummets to the bottom and we lose all of our instruments then we pretty much have to pack up and go home! In the dark of the early morning, from the bridge we all watch in horror as the display jumps up to 12,000lbs.! Our hearts dropped out of our chests as we strained to see whether or not the cable was still there. 

Thankfully, the cable remained attached to the ship, and as far as we could tell so did the CTD, but how? It turns out that the problem was an electrical problem with the sensor on the winch that measures the tension, the tensiometer.  When we went take apart the electrical components of the tensiometer we found that a junction box of electrical wires was half-full of rain water! Uh oh!

It took me an entire day to go through each and every exposed connection and take off the corrosion that had built up.  Afterwards, we recalibrated the tension and it was back to normal.  Everybody breathed a sigh of relief. 

This was by no means the end of our trouble with the Tow-Yo and the winch, but it is the closest to a happy ending we’ve had with it.  I continue to learn an awful lot about how technology and the ocean do not mix easily, but it’s my job to make it work and keep it working!  I am extremely comfortable with my job security as the Marine Techs are working around the clock desperately trying to fix the wealth of challenges that the ship has to offer.  Also, having things break and getting to put them back together is a fantastic way to learn the nitty gritty details of the equipment I’m working with on the ship.  (Just don’t let the scientists know I said that)