Prelude to a Transit: ROV 101
31 August, 2010
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The entrance to St. John's, Newfoundland, by sea
The lighthouse at St. Johns, Newfoundland, one of the oldest in North America
By Michael Dessner
Once the gear was on board the night of the 28th we bugged out in advance of Danielle but I hazard if you weren’t on deck you’d have hardly noticed as far as the ride goes. The first thing you realized was the ship had evened out, not bopping around as much as it does when it’s station keeping for operations. Pretty big difference between maintaining a heading underway, a repetitious rise and fall as you travel the waves at 10 knots, versus occasionally wallowing in the slop when holding position or drifting during Ops.
When the ROV is on the wreck the ship is constantly using its dynamic positioning (DP) capabilities to stay in the exact spot the Phoenix guys tell it to be in. Try doing that using only 2 screws, even with variable pitched props, double tough if not impossible. You’re fighting ocean swell, winds (and resultant surface seas) then top it all off with current; it’s an easy bout to lose for a couple seconds and that’s all it takes sometimes for things to go wrong. DP uses 2 (ea.) bow and stern mounted thrusters to try and bore a 5 meter hole in the ocean. It’s quite cool. And necessary; the ROV operators are holding position over a site that sticks up tens of meters from the ocean floor. Titanic is a jagged, hundreds of tons anchor just waiting for anything unfortunate enough to get entangled in the rusticle covered wreckage. And the ROV team is not just floating Remora over the site looking down; they’re running it up and down the sides, looking at the bottom surrounding the hull, lots of different moves as they ‘map’ it with Billy’s smoking hot 3D cameras. It’s a thing of beauty when it’s going on, but, as you’ll likely hear me say again and again about many things, it ain’t easy.
ROV descent lights, viewed from above
Currents are a major variable. They can run in different directions at different depths. When you consider that you’re working 4 kilometers down on the end of a tether and the only two things you can control are the position of the ship (mostly) and how you fly the vehicle using thrusters to fight against bottom current, it’s a solo dance at the end of a very long line amidst a whirlwind of variables. It’s not at all the same but a decent enough analogy might be trying to dangle a washer on a string out of your fourth floor hotel room window and hovering it directly next to a soda can laying on the sidewalk below. I am going to do a little more sniffing around Phoenix operations, pester the boys a bit and write some more about this. It’s fascinating.
And sometimes a little scary. Everybody loves you when you got it all going on but sometimes when you’re hanging your string in the wind over a tangle of steel 4 klicks down you can get a little hung up. Then it gets real quiet in the labs. Soon nonessential personnel start leaving. Then it’s damn quiet everywhere. The pilots are keeping their cool but if they ain’t sweating it internally, they ain’t human. At the end of the day, everybody has fall asleep alone in their head. But the measure of a true professional is keeping your cool when it hits the fan; that’s how you get the job done. Never let them see ya sweat because that shit is contagious. You move the boat this way and that, drive the vehicle here and there, look around, understand what’s happening and why… and fly that bad boy out of trouble. That’s the gig: high power underwater explorer space ship piloting with your contrail a potential anchor tail. When the vehicle is free and the cheering stops it’s just the end of another day. You wait until you’re on the beach in the bar with your boys before you let anyone know it had your pucker factor up and then it’s all laughs, good natured hard core ribbing and slaps on the back. The Phoenix guys ROCK.
Once the girls were in their huts and Remora was on deck, we dogged it all down and headed to town in advance of the hurricane. At the beginning of a transit home everybody hustles to make sure they’re gear is tied down so nothing rolls around and damages personnel or gear, then usually everyone heads for the rack. You shed the tension of the job, start looking forward to town and for the next 36 hours you take care of processing and lining out your next moves. The busiest people on board at this time are the analysts. They’re caught up handling all the requests from their team mates so the planning can go forward. We have multi beam data that needs to be processed. Mosaics of sonar imaging in two frequencies that need to be made, smoothed, cleaned and tweaked. 14,000 photos, each representing a 7 meter square of bottom that need to be made into a map (if you printed each one onto a standard piece of paper and strung them together the resultant map would be roughly the size of 5 football fields)
Most of that is falling to Andy Sherrell. He’s doing a helluva job. When this is over ask Chris Davino, Dave Gallo, Jim Delgado, Billy Lange if they got all they asked of Andy and more, I know the answer already. But it’s tough when they ALL want something within the next 1 hour. Buggin’ out for the beach; he’d never admit it being happy about it but he wouldn’t deny the providence. And that just ripples out to every one who’s waiting for that data. They all get it, done right, in time to plan for a few days before ops most likely. When we get back out to there this group is gonna be a well oiled machine.
Everything I discussed above has only to do with our data and how it will interact directly with the ROV operations. How this will all fold into the overall product we are working towards making is hard to comprehend. If I understand it correctly, Billy’s HD 3d footage will be “draped” on top of the 3D representations that will eventually be produced by the data we are collecting. It’s going to be a crazy conglomeration of datasets that should be something new, something never before seen. It will really be a 3D, interactive, scientifically accurate visual representation of the wreck. Add that one to the “Never Been Done Before” list of this expedition, right after concurrent AUV and ROV operations.
Wow, two posts that start at the beginning of the transit and I still don’t have us halfway to the beach yet. Sorry, guess you’ll have to wait another day for it. But do read on. We left on the evening of the 28th and arrived on the morning of the 30th and the 36 hours in between were highly entertaining; like no other transit I’ve been on. I am going to see if I can get one of the WHOI camera techs to guest blog and tell the story of the romance that swept up the ship on the way into town.
