Author: Kaitlyn Beardshear Page 2 of 5

This week I’ve been working with the pressure housings more. These are the same pressure housings that I had disassembled and inspected earlier this year. There are almost 60 pieces that need various changes from adding new ports, re-boring previous ports, and surface cleaning. My job is to bring the components to the machine shop, ensure each one has the correct work completed on it, and bring it back to the lab. 

I’ve also been doing some soldering this week. I might be soldering some of the penetrators (which I’ve written about before, each penetrator has 132 wires, there are 8 penetrators, for a total of 1,056 wires to be soldered). I received the components needed for my circuit board. The difference with the circuit board is that the components are surface mount, so the soldering style will be different from penetrator which is soldering wires into a solder cup.

My circuit board! (Currently unpopulated)

One side of one of the penetrators I might be soldering. Hand for scale.

A lot of little tasks were done this week. I built up some connectors for my circuit board so that we can plug everything into it. The most challenging of the connectors being the headphones; it took me a long time to find the pin numbers so that I could make sure the wires went to the correct places. Once I had the pinout it took only a short time to make the connector itself. 

Some of this week was spent testing a navigation device the ship uses. We had to check various readouts including AC resistance, DC resistance, and current draw. It was certainly an interesting task and you can immediately tell which ones are new based on how loud they are when they go off. Don’t have to ask if the button is being pushed if you can hear the high pitched beep!

This week I was able to brush the dust off some of my CAD skills. I spent this week designing a circuit board in order to test the device that communicates between the ship and the sub during dives. I spent a lot of time recreating the schematic. I could have just made a basic schematic that just has the symbols, but I spent the extra time putting in the exact parts I’m gonna be using. This means I can just put all the parts into the shopping cart easily and I know the traces will fit perfectly on the circuit board. After that was finished, I designed the circuit board. I spent some time moving the parts around trying to get them neat and orderly only to have to move them around and mess it up a bit in order for the traces to be run properly. Instead of running the power and ground in traces, I made them into copper layers. This meant that power and ground would be available over most of the board and minimize the amount of traces needed. One problem with that is there will be a circle in the center that isn’t properly connected and I need to run a line to it. Of course the CAD program gives an error but won’t tell you what it is or how to fix it. But I did manage to finish the board and it’s been sent off to be manufactured! 

My schematic

The board design

I ran a lot of tests this week. The easiest of which was testing the Doppler. It helps the sub navigate while underwater. I just had to hook it up to a computer and run the test. The computer took care of the rest and was done in about a minute. The harder test is working with the motor controller. The thrusters are being upgraded and will be controlled in a new way. With that, the motor controllers are being changed. I spent my time this week running through a testing protocol. Each time it did get a little better. Upgrading the power supply was a big help. Some of the instructions are a little vague and I don’t know much about the thrusters themselves so I asked one of the engineers who has worked through the program to help me with it. Hopefully we can get together and get the motor controller fully functional!

The Doppler sitting on top of a wood block. This is normally mounted facing downward at the tail of the sub.

The motor testing set up. At the far left is the laptop that was running the tests. Next to that is the thruster. Then the bunch of wires and the small black box is the motor controller. On the right is the power supply.

Spent a lot of time this week cleaning up some of the lab space. When everything was offloaded from the ship, it kinda got shoved into this room. I sorted, organized, and put away some of the stuff to clear off bench space so I could actually work with others instead of being in a separate lab. Once the space was cleaned out, I set up three computer workstations. One is a general purpose computer where I or anyone else can work. Another is a computer that connects to a motor controller which then connects to a thruster. A couple of weeks ago I built several wire harnesses; they’re going to be used for this set up. The thrusters are being upgraded and are controlled in a different way than the old ones. With that, the new software needs to be tested with the thrusters. Another station is set up as a sub simulator. One computer generates fake sensor data which is then sent to another computer that reads it as real data. This can be used to both test the way the sub reads data and the way the sensors send data. We can also hook up actual sensors to the computer and verify that the sub interprets the data correctly. This is something I will be working on next week with testing the Doppler for navigation. 

This week I spent helping one of the engineers gather data for a prototype they’ve been working on. The device is a level sense: it measures how high the water level in a tube is to know how much water is in the container. My job has been to run experiments at different pressure levels to see how the water level is affected by air pressure and water pressure. Some of the experiments were very hands-on in that I took a data point after every change in pressure while others had steady pressure and I took a data point every 10 minutes. This was a little more challenging in trying to multitask: as soon as I would get settled and into a groove with my second task, the timer would go off and I’d have to collect another data point then back to my task then timer goes and so on. But I have been told that the data is good and that the graphs I made were very helpful in the device presentation.

The test set up. Water is pumped into the tubes. The air pressure is controlled by the regulator attached to the tank.

A look at the data screen. The probes inside the tubes send data to the computer which is then graphed.

As an update from my previous blog, my inspection report is now 160 pages long. It’s as complete as it’s going to be for a while. Decisions need to be made about whether to use the current end caps and remachine them or to make new ones. It also needs to be decided if we’re going to use the spare connectors made of the same material or if new ones will be ordered out of titanium. I spent time unsoldering one of the failed connectors. We’re hoping that we can reuse the wires. The problem is that they may just be old and not optimal after being subjected to dives for years. Ideally we will be able to reuse them because of the pins at the end of the wires; the company that originally made them has closed and no one makes a comparable product. If we cannot reuse the wires, then we may have to redesign a lot of the electrical components in order to accommodate new pins. Also it’s a lot of work to cut several feet of wire for each pin of which there are 66 per connector and there are 8 connectors (1,056 wires in total). I didn’t think unsoldering the connectors would be too bad, it’s just heating the solder and pulling wires how hard can that be? Again, there are 66 pins on the connectors in concentric circles. As you get closer to the center, the pins get closer together. Trying to hold the iron against the solder without melting any of the wires is a challenge but I am up for it. 

A halfway unsoldered connector

It doesn’t feel like I’ve been busy this week but I have been doing a lot: I disassembled 7 chassises and end caps, all of the pieces that fit have been put through the ultrasonic cleaner, everything has then been inspected and all damage documented. Taking apart the chassises is a feat in itself. When they were put together, it was one bit at a time so there’s not an entirely logical way to take it apart. Undoing different sorts of connectors here and there trying to access some wires that are deeply buried or taking apart multiple circuit boards in order to undo one screw. Some of the screws are coated in a ridiculous amount of loctite and are basically super glued into position. Taking apart one section and putting it back together only to find out I have to take it all apart again. The whole time I’m doing this I’m thinking of how I can make it easier when I have to put them back together in a few months. The report I’ve been making to document all of the damage is up to 140 pages of descriptions, pictures, and color coded charts. It seems when you put something in the ocean repeatedly and don’t examine it for 7 years, it isn’t pretty when it comes apart. I cannot describe the absolute terror upon my senses the smell of old sea water and aqualube makes. I can only hope that after this week I won’t have to deal with it for a long long time.

A chassis and end cap before disassembly

After disassembling chassises and end caps

All of the connectors that I have been working on have failed their inspection. The end caps have been measured and turns out they were made improperly. The drawing was wrong, which lead to the end caps being made incorrectly, which lead to a gap that the o-rings extruded through. With the o-rings disfigured, sea water was able to get in and corrode the metal. Ideally all that needs to happen is to fix the end caps and then the connectors should be fine. This week I also learned the importance of units as I torqued the connectors 12 times higher than they’re supposed to be at. Luckily this isn’t a terrible mistake; I just need to redo them at the correct torque.

One of the connectors had a hole in it! The corroded area measures 4 mm by 4 mm with the hole being 2 mm deep!

I also got to use this little wrench. It’s so cute!

In the newest update of work starting and stopping, while taking apart an end cap and its connectors, I found some of the o-rings had degraded. After finding a few like this, a meeting was held to figure out what to do next. It was decided that I’m going to take apart all of the end caps and connectors to check the status of all the o-rings. Turns out most are degraded and some had even failed allowing water into the connector. I’ve been taking pictures and documenting everything I’m seeing and doing so hopefully a maintenance procedure can be made to check the o-rings more often.