Sue Oltman: Getting My Sea Legs, May 22, 2012

NOAA Teacher at Sea
Sue Oltman
Aboard R/V Melville
May 22 – June 6, 2012

Mission: STRATUS Mooring Maintenance
Geographical Area: Southeastern Pacific Ocean, off the coast of Chile and Ecuador
Date: May 22, 2012

Science and Technology Log

It’s finally the day we will leave port!  I’m awakened by the feeling of my bed shaking and a crash of something falling, this could have been an earthquake.  The science party boards the boat after breakfast and spends a lot of time fastening all equipment down and securing it to shelving; even my laptop needs to be affixed to my desk with Velcro.

My stateroom is on the 02 deck, which is one floor below the main deck. I’m in 02-50-2 with a private “head.” Everything is made of steel (even the toilet and shower) and is bolted down, too.

As we move out towards open  ocean, the R/V Melville – all 278 feet of it –  is moving northwest at about 11-12 knots and all seasoned hands comment on how calm the seas are. However, there are factors such as pitch, roll and heave which I am not accustomed to!  Ocean conditions affect the ship with  roll of about 3° to 5°  – swaying back and forth to the left (port) and right (starboard.)  Pitch is the hull tilting forwards or backwards and is about 1 ° or less.  Heave is vertical displacement of the ship and is a meter or less. The roll starts getting to me after dinner, despite the sea-sick medicine! Fortunately, after lying down for a while, the sickness passes.

Next, I went up to the lab where all the monitors are to see what I can learn about our course. Watching the multi-beam sonar display (from the Bathymetry XTD) as the ocean floor drops out from below us is fascinating. An array of 191 SONAR beams maps it out. The colors appear like the depth color key on classroom maps we use of the ocean floor – dark blue where deepest and yellow or even red where it is shallower.

The monitors showed the ocean floor depth as it dropped from 2500 m to about 4700 m in an hour or so. The ship was beginning to sail over the trench!

Two safety drills were conducted – a fire drill and an abandon ship drill. There was also training on the scientific equipment we will deploy, the UCTDs  (underway conductivity, temperature and depth probes), and ARGO drifter buoys. Sean Whelan led the class on UCTD training and Jeff Lord prepped us on the drifters. These smaller buoys will be released and will float freely, carried by the currents.

The UCTDs will be deployed hourly around the clock on the aft deck (back of the ship.) Salinity and density are derived from these values. The probe is dropped into the water, will sample for about 2 minutes to 400 m or so and then be retrieved. The casting line is then rewound onto the spool to be ready for the next deployment like a sewing machine bobbin being wound.  The data is transmitted to the computer via Bluetooth when a magnetic key is inserted to activate it.

Everyone was trained how to use the winch as they will need to use it on watch. Each watch has 3 people and is 4 hours long, and then you have 8 hours off. My assigned watches are 0400 – 0800 hours and 1600-2000 hours (4 to 8) so I will need to alter my sleeping schedule! Those on watch must stay in the downstairs lab and conduct UCTD releases during those hours. The instruments inside the UCTD are very sensitive and costly and must be handled very deliberately.

There is one more session. Keith – the ship’s “res tech” or resident technician – conducts a CTD handling class. The “rosette: is the circular frame in which water sampling devices called CTDs are placed to take water sampled in international waters. These are different from the UCTDs because deep zone water is sampled for salinity and temperature. This will be done about 7 times on this cruise. It is large and the instruments are housed in a sturdier casing so it is heavier and the winch operator must lower this into the ocean with a crane.

We are looking forward to be seeing some great sunrises and sunsets from our research vessel during watches!