Tuesday, June 4, 2013

Langseth: The birds

It's 6:30am ship time (Spanish time). The 12am-4am shift finished deploying streamer 4 at about 12:30am, and since then we've been waiting for the sun to rise and the seas to calm before putting out the paravanes and continuing to deploy streamers 2 and 3.

Most of the science group has been working in 4 hour shifts thus far - 4 hours of work and then 8 hours of time for other things each 12 hour period. The last day or two, I was using my 8 hour rest periods to eat a couple of saltines, lie down, and attempt to ignore the rocking of the ship, but I must be getting used to the seas (and they are calmer!) because I can now do other things like read papers and look at a computer screen.

We have been collecting data almost since we left port. We are mapping the bathymetry, collecting gravity data, recording ocean current directions, etc. Since we entered our 3-D box area yesterday, it's been exciting to identify fault scarps in the bathymetry.

Donna mentioned in her previous post that once a streamer is in the water, its location is monitored and it can be moved around using winged devices called "birds" that are attached to it. Imagine a number of actual birds holding a cable in their talons at an even spacing while flying. Our mechanical birds are not so different, except they are flying the streamer through the water. We can see where the birds are on a computer screen in the lab, and we can control the depths of the birds by remotely moving their wings. When a streamer goes into the water, it can take some time to get the weighting right and then for the birds to dive the streamer down to the desired depth (generally 8-12 meters below the sea surface).

Marianne Karplus
3rd June (posted late due to internet outage)

Assembing a bird to be attached to the streamer.
Birds for streamers 2 and 3 waiting to be deployed.