Posted by: adorsk | November 22, 2007

More Moorings

Just got back from the Oceanus’s last cruise for the year. I was out in the gulf stream, Northeast of Bermuda, where the ship recovered four moorings.

Mooring Recovery

The science party for this cruise was headed by D, a WHOI researcher who designs mooring instruments. He and his group have been involved in the CLIMODE project (CLIMODE home page), multi-year project for studying the formation and transport of water masses and the Gulf Stream.

D deployed moorings last year in the Gulf Stream. This cruise we recovered them.

Mooring recovery is one of the most labor intensive activities the ship does. It requires many people on deck, involves high-tension lines and chains, and it takes a long time. I wrote about it one of my earlier posts: Underwater Rodeo.

AS I wrote earlier, first you must find the mooring. To give you an idea of what this is like, check out this picture.

Find the Mooring

Do you see the yellow hard hats? No? Here, I’ll give you a hint:

Find the Mooring, Hint

This is from about 200 m away, not very far. I suspect that people who recover moorings must train for hours with “Where’s Waldo” books.

Hooking the mooring comes next. Here’s J from the WHOI rigging shop with the hook:

Hooking a Mooring

The next bit involve raising the mooring float onto the deck with the crane, and then attaching the mooring’s main line to a winch. This is this most dangerous part, as the mooring line is under high tension and the mooring float is unwieldy.

After the mooring line is attached to the winch, the next three to four hours consist of hauling up floats and instruments. The floats (called ‘hard hats’) are large glass balls encased in yellow plastic. Each one is about 1/2 meter in diameter. If you’re in the market for a giant glass ball (would-be wizards, fortune tellers, people who want to take their fish for walks), make friends with the WHOI rigging shop. Mooring instruments include thermometers, salinity sensors, current meters, and fluorometers for measuring biological activity.

Mooring Ops

When the last instrument is on-board, we cut loose the mooring from its anchor and lash everything to the ship. And that’s a recovery!

The whole process has its own vocabulary. There are ‘tuggers’ (motorized line pullers), ‘wuzzles’ (nasty knots in the mooring line), ‘diapers’ (cloth wrappings that go around sharp wire points where instruments were attached), and ‘hard hats’ (the floats).

CTD

After we got the moorings we headed back to WHOI, doing CTD stations along the way. CTD stands for Conductivity, Temprature, Depth. It’s a collection of sensors and bottles that gets lowered down to collect water samples and measure properties of the water column. It’s the basic bread and butter of oceanography.The CTD package has 24 bottles in a ring around a core of sensors. In total it’s about 1.5 M tall and a bit more than a meter in diameter. Here’s a picture of it being deployed:

CTD Deployment

Each CTD station is called a ‘cast’. Our casts went down as deep as 4000 m. It takes about an hour and half just to lower the CTD down that far. On the way back up, we fire the bottles every few hundred meters to get samples of water from each depth. A deep cast can last three to four hours.

This trip we had some trouble with the CTD. During our first few casts we got glitches in the data, and bottles wouldn’t fire. This meant I had to re-do the termination that connects the ship’s winch wire to the CTD. Unfortunately, doing a new termination didn’t fix the problems. It turned out the problem was a cable on the CTD itself. Just another example of how what can break will break when you’re at sea.

Lumps

While we were steaming from the last mooring to the first CTD site we ran into some weather. For two days it got rather lumpy, 8-10 foot waves and 40 knot winds. There were many times when the ship rode onto the peak of a wave. For about a second the ship would hang. Then it either (a) slid gently off onto the crest of the next wave, or (b) did a roller-coaster nose dive into the bottom of the next wave, with a resounding crash. Going to bed in this weather was like trying to sleep on a tilt-a-whirl.

Back Home

Now I’m home for a month. Sometimes when I get back from the ship it takes a bit for my mind to adjust. When I woke this morning I had the strange sensation that my entire room was moving as if I was still at sea. Another meaning for ‘home sick’?  I suppose I’m still looking for balance in my life.  Usually this goes away after a few days.

I’m realizing there are lots of things I like about The Cruising Life. Each cruise is almost like a new job. I go out, come back, and feel changed. Discrete and punctuated intervals of work act like milestones for life. I can go out on a cruise, write down things I knew at the beginning, come back, write down what I know then, and see what has changed. Perhaps in a steady job things seem to blend together. And I also get to meet many incredible people. From each one I try to pick up something new. Melville said it best, A whale-ship was my Yale college and my Harvard.

I’ll be home until December 27th. Then I’m going to Brazil!  I’ll be back on the Knorr, doing a cruise from Natal, Brazil to Ascension Island in the South Atlantic.  I’ve always wanted to go to Brazil.  I’m even learning a little Portuguese.  Fala o senhor português?

Ascension should be pretty cool too.  It’s the Southern capital of Mittelohf-nohweir.  1100 people and lots of birds.  Check back in January to find out how it goes.

Thanks for reading.

Some Miscellaneous Pictures

The WHOI brass band awaited us at the dock. Have I mentioned that WHOI is a great place to work?

WHOI Band

T & I in the science party test out their foul weather gear on the bow

Bow Spray

The Rainbow Cast

CTD Rainbow

Deck Abstract

Deck Abstract

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Responses

  1. Alex — Just came across this after browsing (and updating my profile, hehe) in the Alumni Directory. I really enjoyed reading it! “That’s a Moray,” tehehe. Hope things are going well for you!


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