WEDNESDAY, 03.11.09

0742: Days 23 & 24 ( March 9 & 10)
Greetings all. Tonight we are going to follow both vehicles individually. Just too confusing to do a chronology,

When last we left off with Ginger she had been deployed in the early hours on March 8th to survey box 9b. She was retrieved at 0206 on the 9th from her survey of box 9b after another successful mission. When she came to the surface we had a small issue with the grappling gun. The first shot was on target, although it was a bit high and long. If this happens, the hook goes well past the line it is designed to recover and a large arc of line soars over the top of water where it can be blown by the wind over the top of the float.

The hook firing is a two-man job: the shooter makes sure the hook goes over the line that is floating between the released recovery float and the vehicle, and the other person arrests the line. As soon as the hook hits the water, the second person needs to grab the line that is paying out over the side of the ship very quickly. He wants to grab the line just as the hook hits the water or the excess line in the arc over the surface of the water can be blown back over the float and make it impossible for the hook to grab the float recovery line. Reach in too soon and you can short the shot. Reach in too late and the line blows over the float. Reach in too far and you end up with a nasty rope burn across your wrist (I know this from experience).

During this recovery the guy reached in too late and when we re-charged the gun for a second shot, it failed to charge and fire. The team reacted admirably. Instead of running around and basically trying to snag the vehicle as it drifted down the side of the ship, everyone took a step back and calmly did their thing. The gun team kept working on trying to charge it. Another man made three attempts to hand throw a grappling line over the recovery line. As the vehicle drifted toward the ship, Joe Lepore –  showing great calm and command of the deck — had the vehicle operator drive the vehicle with modem commands from the control room over the radio. The vehicle was amidships so Joe could see clearly that the lines were clear of the propeller. Joe simply had her back up for a second or two, and then had her go forward for a moment.

Joe’s been doing this for about a week (directing the vehicle instead of the boat in close quarters), but this was the first time I had witnessed it and it was slick. He was so calm and matter of fact about it, a true leader on deck to be sure. That’s the difference between leading and just charging in and reacting. A guy who is new and green runs about and yells and reacts. A leader stays calm, does not move from where he needs to be and quietly directs the efforts of others as he leads by example. When a deck hand in a perceived emergency gets it into his head to go running off into a corner to try his own solution, he will usually first look over to the deck boss. If he sees the boss running off to another corner, he is free to do as he wishes; but if he sees the boss standing calmly, talking into a radio and working the problem, he freezes his eyes on him like a deer in headlights, waiting for direction. It was quite a masterpiece of leadership. Ask Joe about it and he probably won’t even remember it; just another day on deck, nothing special. Ask his team and they will tell you he was all over it.

OK, back to the girls. Ginger came in and her sonar data was in good shape, but there was a glitch. When her Inertial Navigation Unit aligned with the GPS system at the surface before going into the water, the data was buggy. Really, it was just one of those things. We are looking into some programming that requires a certain level of information now, but at the time we could not have known. If we were not in the midst of such technical difficulties this would have gone down as a simple learning curve, but given our current productivity it hurt badly. The navigation error led the vehicle to constantly try and adjust itself against the navigation it was getting from the DOT; when it was away from the DOT on the far side of the survey it would run off the line some 30 yards, then readjust and repeat itself until it was within full comms with the DOT. The data at the far end of the box was full of ‘holidays,’ empty spaces created by the vehicle constantly adjusting itself on its long axis.

Ginger’s navigation data was next to useless. While we had some good sonar data, we would have to run this line again. Very disappointing after two successful runs for Ginger in a row. At 0630 on the 9th Ginger was sent again to survey box 9b. She was recovered at 0530 the morning of the 10th with no issues. Her data was solid. She was launched at 0954 to survey box 10b and she is down there working away. This will be her fourth completed mission in a row with no issues. Ginger is back in the spotlight.

Mary Ann, however, is experiencing some serious difficulties. You will recall she was suffering some issues with a depth-related failure, and we last sent her down to do a diagnostic lane after we had switched her transducers around to determine if the problem was a cable harness failing at depth or a transducer. At the time, we hoped that it was a failure in her cables since they are much easier to repair and we can try to cobble-together various solutions to get a workaround. When she came up, though, we got the worst news possible: it was her transducers that failed and these are not repairable; they are constructed in a way that makes them impossible to disassemble. Indeed, we will have to send her bad transducers back to the manufacturer and they will run them in a pressure tank to take measurements and gather data, and then they will likely destroy them to see the physical realities inside them. This was dire news. We only had two remaining transducers not in service aboard Ginger, and one of them had been previously removed from service as questionable.

We installed that questionable unit in place of the one we knew to be failed and sent it down for a single lane run. When she came up, we found that the questionable transducer had also failed. This is a major blow to our operational capabilities. Essentially, we have now lost the ability to use Mary Ann in long-range mode until we can get a replacement set of long-range transducers back out to us. While we know that Ted is coming, those parts are not available for his trip. The lead time for these units is usually eight weeks and we have obtained a set under construction that will be available to us in two weeks, just in time for someone to hand-carry them to us when we go into Samoa for a changeover and re-provision. We now have three failed long-range transducers out of six, which leaves us only one spare for Ginger should we need it. This has necessitated we take our only pair of short-range transducers and mount them in Mary Ann. To say everyone is stunned just does not do justice to the situation. Transducers are notoriously tough and usually very reliable. In the past I have seen them run into the bottom of the ocean, get scraped along the side of a reef, come up and still function on the next dive. Our team at Woods Hole, along with Dominique and the Hydroid group, are all scrambling to get some answers and relief from EdgeTech and the manufacturer, Jetasonic. I am told we will have final numbers and plans from EdgeTech today on how to sort these problems out.

So, what do we do in the meantime? We drive on. Ginger is making data and we do have a short-range set of transducers for Mary Ann to use.

A brief lesson on transducers and how they work: In layman’s terms, transducers basically convert electrical energy into sonic energy, which they then shoot sideways on a downward angle at the sea floor. The same piece of equipment then senses the return of that sonic energy and the computers translate that data into an image of the sea floor. It is not a picture by any means, only a representation. Our plane may look like a plane or it may look like a square, or a cross depending on how much energy is reflected back, at what angle the energy hits the reflective surfaces and how far it is from the transducer. Lower frequency sound waves travel farther and thus give you a longer range. The set of transducers we have been using are 75/410’s. In other words they have two frequencies; 75 kHz, a low frequency, long-range setting and another channel that shoots out 410 kHz, a higher frequency and shorter range setting. The set we have just loaded onto Mary Ann are 230/510.
Okay, time for some real confusion. The altitude you fly your sonar off the bottom of the ocean floor is a function of the range of the sonar. Generally, you fly your sonar at 10% to 15% of the range of your transducer (e.g. 75 kHz sonar has a range of 600 meters, and so you fly it at 60 meters off the bottom of the ocean). The new set of transducers has a range of 350 meters, so we are running Mary Ann 35 meters off the ocean floor. The benefit of shooting a shorter range is that we get a lot more information in the record. It significantly increases our chances of detecting a smaller target because we have a higher resolution in our imagery. The danger is we are working that much closer to the bottom of the ocean floor, and if we run into a significant obstacle, we run the risk of running into it.

Our vehicles have what is called a pencil beam sonar obstacle avoidance system. There is small sonar in the nose of the vehicle that looks forward and if it detects there is something in front of it, the prop stops turning, the vehicle floats up until the pencil beam no longer ’sees’ the obstacle and our girl goes along her merry way. Our first trip down with the new transducers showed us this system is functioning perfectly, even with the reduced range. There was some concern before Mary Ann came back up that the reduced altitude might endanger the vehicle.

Ted Waitt asked me to look into this and as of our last communication, we were discussing slowing the sonar down. However, I am happy to report that the vehicle, on her first dive with the new sonar transducers, successfully avoided contact with a 1,000-foot tall ridge directly in front her. There was some interference in the record and it was determined the vehicle needed to have its buoyancy adjusted since the new transducers are lighter than the old ones.

Mary Ann launched yesterday, March 9, at 1659, and she was successfully recovered the next day at 1732. Her new transducers showed some slight interference in the port channel. The data was very readable and good for her mission, but since we are gun-shy of any transducer issues, we are looking at any difficulties very closely. We want to know if there is a problem with the cable, transducer or bottle. It could also be the channel (frequency). Her transducers were switched over so we might diagnose any issue. As well, she was re-trimmed with some soft ballast into her nose. She was launched again at 2202 on the 10th, and is currently on bottom finishing up her survey of box 9a. With half the range of her previous configuration, she was only able to cover half a box, so she will finish the box tomorrow afternoon.

We anticipate recovery of Ginger from her survey of box 10a tomorrow (actually today for me) March 11th at 0400. Mary Ann will be back from her survey of the second half of box 9a on the 11th around 2100.

I will try to get back to a daily schedule soon. Thanks.

0854: Ginger Is Back
A completed mission and good data. I’d like to point out that if you discard the user aborts and the sonar transducer failures, which is really a manufacturer meltdown, the vehicles have now completed 13 missions in a row. This totally got by me until I realized Ginger had just completed her fourth successful mission in a row with no issues whatsoever. The sonar issues had distracted me to this. Right now, the girls and the systems are running well. We had two user errors and a single component system failure, but the overall platforms are doing well.

I would also say that the team morale right now is very, very good. These guys are working exceptionally well together. That’s all I’m gonna say about it.