Author: Christopher McHugh

Argg Matey’s,

Thanks for tuning back into the adventures aboard the R/V Marcus Langseth. This week has been full of surprises. From blue whales to hydraulic malfunctions; join me as I retell last week’s adventure.

First our OBS (Pictured) recovery hit a few snags. We had one that was unable to communicate with the ship and couldn’t be recovered (we will try again next week). Another OBS had an O-ring fail which caused the logger compartment to flood and react with the lithium battery. This caused an explosion/melting of the logger and part of the containment structure. The data for this OBS was lost. After the recoveries we deployed the streamer which is a 8km array of hydrophones spaced 25 meters apart. We control the depth of this streamer (between 11-13 meters) with 29 “birds” or radio operated diving modules. They are equipped with “wings” or flukes which can be changed for the desired depth. Each “bird” has a pressure transducer used to measure its depth below the sea surface. We simply tell the birds to dive to 12 meters and they adjust their flukes till they are there and then level out. We also mounted acoustics on the streamer one at the beginning and one at the end to give us range and bearing of the streamer.

After we finished with the streamer I hoped down to the gun deck put on my harness and we deployed the guns (which requires hanging over the back of the ship getting soaked by waves running up the slip way and it always seems to be raining when we put the guns out).

The idea behind the streamer and gun array is to measure the two way travel time (streamer) of the reflected/refracted sound waves (guns).

But nothing ever goes as planned. While deploying the streamer we blew a hydraulic line. After quickly dealing with the leak and isolating the line, we came up with some clever ways of using winches on other hydraulic systems to finish deploying the streamer. Seeing and being part of a crew who can work together so quickly and efficiently to overcome un-foreseen problems was inspiring.

One thing about science/ship life is it gets very hectic and busy then….nothing. You just sit around for 12 hours doing your logs and monitoring instruments. Maybe some ship maintance like cutting angle iron for building shelving or re-greasing machinery. This is how it’s been the past three days. Except for a few blue whale sightings that we are required to shut down the guns for, it has been quiet. This is good for science but boring for us lol.

I am sure things will get more interesting soon they always do!

Till next time

–          C

Well mates let me get you up to speed since my last post. We have left the port of Bermuda and are currently in the middle of the Atlantic on our way to the Rainbow Massif we are studying on the Mid-Atlantic Ridge. I have been on a 12hr shift rotation starting from mid-night until Noon. For the first four hours I work on deck with the gunners and marine techs. The next eight I am in the main lab with the science party. Basically we have been trying to get the seismic guns ready for deployment. There is alot of work that has to go into to these huge expensive pieces of equipment. Ok I am going to keep this simple; what you are looking at in the photo below are seismic air cannons or guns (used for multi-channel seismic surveys) that are attached to big floatation devices. The coiled rope (green) are specif lengths that keep all the guns at the desired depth (9 meters). These are towed behind the boat as well as 6 kms of streamers (hydrophones) that recieve the returned signal produced by the air cannons after it has reflected/refracted through the subsurface and back towards the sea surface. We are also running multibeam and …

OK thats enough information for one day, if I tell you everything now there will be no suspense and anticipation for the next one.

Well mates, thanks for tuning in. Today is my third day on-board the Langseth and what a busy three days its been. When I fist got on-board the science party was not scheduled to arrive till the next day. So I quickly offered my services to the crew and techs and was put to work immediately. Unfortunately we are stuck in Bermuda with a rudder malfunction and although the science party is on-board they have nothing to do till we shove off. So I have been spending my days working on deck, splicing rope, cutting chain, testing winches, and preparing for deck operations while at sea. I will put up some pictures some time tonight or tomorrow. So stay tuned for more exciting insights to live on a research vessel