Wesley Struble, 26 July, 2010

NOAA Teacher at Sea
Wes Struble
Onboard NOAA Ship Ka’imimoana
July 8 – August 10, 2010


Geographical area of cruise: Equatorial Pacific from 110 degrees W Longitude to 95 degrees W
Longitude
Date: 26 July 2010

Weather Data from the Bridge

Position: 8 degrees South Latitude and 104.5 degrees West Longitude
Cloud Cover:
5/8 with cumulus and stratocumulus clouds
Visibility: 10 nautical miles
Wind bearing: 150 degrees
Wind Speed: 17 Knots
Wave height: 2 – 3 feet
Swell Height: 6 – 9 feet
Atmospheric Pressure: 1016.6 mb
Temperature: 23.7 degrees C (74.7 degrees F)

Muster Station 4 on the boat deck and the Life Raft

The sea has been rough the last several days with large swells up to 12 feet or more that are really causing the ship to pitch quite strongly. The captain has had the anti-roll tanks filled and that has helped but the ship still pitches and rolls quite a bit. I am typing this up on deck sitting at a picnic table because the chair in my room is a typical desk chair with small wheels and if I use it I wind up rolling all over the room.

We are approaching the southern extreme of the TAO at 110 degrees West Longitude. After we visit the last buoy on this line located at 8 degrees south latitude, we will plot a course due east and head for the 95 degree West longitude line (about 900 nautical miles east). We expect to arrive there in a few days after which we will do maintenance on the buoy located at 8 degrees south latitude and then proceed north following 95 degrees West longitude.

The KA skiff

Today we had two emergency drills (as we do every week). These drills are not the same as we have in school where alarm rings and the principal measures the amount of time it takes to get the entire school evacuated. On a ship it is much more complicated because if (for example) there is a fire we cannot simplyevacuate the ship and call the fire department – we are the fire department! With this in mind there is a detailed plato follow every time there is a drill. are three common emergency bell signals and a drill that matches each. Three long bells signal that a man is overboard.this happens every person has a stationwhich they are required to report.

My station is the buoy deck (the aft part of the ship) and my job is to find the person in the water, point to their location, and not lose sight of them. This might seem straightforward, but with the moving of the ship, large waves, and enormous swells (behind which a floating person can easily disappear) it makes it a bit tricky.

Immersion Suit
Immersion Suit

During man overboard there are many people acting as spotters placed at different stations on the deck so that the location of the man overboard is always known. Once the location has been established the skiff will be lowered into the water and the person retrieved. Six short bells followed by one long bell is the signal that means abandon ship.

As with all drills every person has a specific station to which they are to report and has particular duties for which they are responsible. If we were actually required to abandon ship then my first task is to report to station four which is located on the port side of the ship on what is called the boat deck. Once there the officer in charge of the group takes role to make sure all are accounted for. We are all required to bring three things: a life jacket (which you don immediately), your “Gumby” suit (a kind of water survival suit that keeps you warm and dry in cold water), and a small sack containing a pair of long pants, a long sleeve shirt, and a hat (all for protection from exposure).

My job is to deploy the Jacobs ladder (this is the ladder used to climb down the side of the ship to access the inflatable life raft) and bring several large jugs of drinking water. In addition, if no one else is available then I would also deploy the life raft.

A fire drill (or collision) is represented by one long (longer than 10 seconds) continuous bell. During a fire drill I am to report to the mess (with several other people) and act as a runner and await further instructions. Fire drills usually entail some sort of scenario where a mock fire is reported in some part of the ship. There is usually a discussion before the drill to be certain that everyone understands what this particular drill is trying to accomplish. Our first fire drill was designed to have a mock fire on the boat deck caused by ruptured or leaking fuel cans. Our second fire drill was a scenario designed to respond to a fire with a lot of smoke in the galley. These drilhave been a real learning experience for me. They are helpful because they build confidence and cut down immensely on confusion and response time in case of a real fire.

Me in my Gumby Suit
Me in my Gumby Suit

Personal Log

Up till this point I have been pleasantly surprised at how cool and breezy the cruise has been. I expected that the temperatures would be in the 90’s and the humidity in the same range. However, the temperature has rarely reached 80 degrees F (most of the time in the mid to upper 70’s) and even though the humidity has been high the constant breezes have kept it very comfortable. In addition, much of the cruise has taken place under various amounts of cloud cover. We have been at sea 19 days and only a handful of them have been clear and sunny. In fact, it has been much hotter at my home in north Idaho than it has been here on the equator. I have lived in equatorial regions before so I know that this is definitely an anomaly – but I hope it continues.

Early Evening over the East Pacific

Wesley Struble, 23 July, 2010

NOAA Teacher at Sea
Wes Struble
Onboard NOAA Ship Ka’imimoana
July 8 – August 10, 2010

Mission: Tropical Atmosphere Ocean (TAO) Cruise
Geographical area of cruise: Equatorial Pacific from 110 degrees W Longitude to 95 degrees W Longitude
Date: Friday, 23 July 2010

Weather Data from the Bridge

Current location: 4 degrees South Latitude & 110 degrees West Longitude
Cloud Cover: 5/8
Cloud Type: Stratocumulus
Visibility: 10 nautical miles
Wind Bearing: 100 degrees
Wind Speed: 20 Kt
Wave Height: 2 feet
Swell Height: 5 – 7 feet
Barometric Pressure: 1015.5 mb
Temperature: 24.8 degrees C (76.6 degrees F)

Science and Technology Log

There are a variety of buoys used by NOAA in the Pacific Ocean. One of the more interesting is the ADCP buoy. ADCP stands for Acoustic Doppler Current Profiler. This buoy is anchored to the sea floor like most of the other buoys deployed on this cruise. The major difference is that the ADCP buoy does not float at the surface but rather is tethered with a line short enough to keep it submerged approximately 300 meters below the surface of the sea. In addition, it is only deployed with the TAO buoys at the equator and not at any of the other TAO buoy locations. The buoy’s name defines its function – current profiling – using acoustic signals (similar to sonar) the buoy provides a profile (or vertical map) of the ocean currents from the depth at which the buoy is tethered to the surface. The ADCP is able to measure both the speed of the current and the direction in which it is moving. Even though the TAO buoy at the same latitude is generally visited more often, the ADCP buoy is visited only once per year. During the visit the buoy is retrieved, cleaned, damaged parts replaced or repaired, data downloaded, batteries replaced, and sensors upgraded (if necessary).

Buoy with newly attached ADCP unit – A
KA skiff at the ADCP buoy

The flotation component of the buoy is a large orange sphere just over four feet in diameter. This float is made of syntactic foam. In general, foam is a mixture of two substances: a gas phase in a solid or liquid phase. Syntactic foam should not be confused with the common foam with which we are all familiar (like the typical Styrofoam coffee cup). Most of these foams are generally composed of expanded polystyrene (a thermoplastic polymer) where the gas phase is air and the solid phase is polystyrene. Syntactic foams on the other hand use other substances for the components.

The ADCP acoustic transmitters & receivers

One of the more common syntactic foams uses small glass spheres 10 – 200 micrometers (millionths of a meter) in diameter. These glass spheres are filled with air during the manufacturing process. The spheres are then mixed in with some type of epoxy resin and allowed to cure to produce the foam. The buoyancy of the foam is affected by the size, number, and wall thickness of the glass spheres. Some of the applications that typically utilize syntactic foams are the manufacture of radar transparent materials, acoustic attenuating materials, and more specifically deep sea buoyancy floats. Our float is anchored to the sea floor with a large (several thousand pound) weight that prevents it from drifting. The material used to attach it to the anchor is very stable and exhibits little elongation under tension, thus keeping the buoy consistently at the same depth. The payload (the ADCP itself) is approximately 1 meter long and about 20 centimeters in diameter and is mounted in a circular well that is bored vertically through the center of the float. The ADCP has four sending/receiving units mounted at the top of the main body. One can see these in the photographs. These units send and receive a 75 kHz signal that reflects (echoes) off the sea/air boundary and returns to the buoy.

When we were close to the location of the ADCP buoy one of the scientists activated an acoustic trigger that released the buoy from its sea floor mooring anchor. Since it was almost 1000 feet under water it took a few minutes for the float to reach the surface. When the buoy was spotted the ship made a slow pass to visually inspect the float and to launch the skiff. The skiff towed a long and very strong line from the ship which was then attached to the top of the buoy. At this point the skiff was brought back aboard. The ship then came about so that the buoy was directly a stern. When all was ready the winch began to retrieve the line and slowly bring the buoy on board. When it reached the deck of the fantail it was made secure and the tether line (that attached the buoy to the anchor) was tied off to a chain on the ship’s deck.

Working on the ADCP buoy on the fantail of the      KA – B

The buoy was then disconnected from its tether line and the line was attached to a large winch and all several thousand meters of it was rolled onto a number of large empty spools and stored on board. While the anchor line was being retrieved the science crew downloaded the stored data from the ADCP and prepared the buoy for redeployment. When the deck hands were ready the process was reversed. First, the tether line was attached to the buoy and it was lowered over the fantail. Then the line was slowly played out. When the ship was in the appropriate position she began to move forward as the crew played out line. When they reached the end of the line a large (several thousand pound) anchor was attached, lowered, and released. This entire process took the better part of a day.

Crew member Nemo McKay & Scientist Will Thompson retrieving the ADCP buoy

Personal Log

I have enjoyed getting to see the crew work together. One can tell that they clearly get along well and appear to enjoy working together because of all the friendly banter that passes between them. I have been impressed with how conscious they are about safety. I have been able to begin participating in some of the work deck activity during the buoy operations and it has helped in my understanding of what actually takes place. It has also helped me to get to know a number of the crew members better.

“Did You Know?”

Did you know that the greatest buoy equipment problem that occurs in this area of the ocean is vandalism? Many of the buoys are damaged, stolen/cut loose, or destroyed. This might be done either out of anger and frustration, for financial gain (the buoys have quite a large mass of aluminum framing and electronic equipment), or by accident. Regardless of the reason, much time, data, and financial resources are lost and consumed in maintaining TAO array in the Pacific Ocean.