Spencer Cody: What Remains Unseen, June 17, 2016

NOAA Teacher at Sea

Spencer Cody

Onboard the NOAA Ship Fairweather

May 29 – June 17, 2016

Mission:  Hydrographic Survey

Geographical Area of the Cruise:  along the coast of Alaska

Date: June 17, 2016

Weather Data from the Bridge: 

Observational Data:

Latitude: 55˚ 10.643′ N

Longitude: 132˚ 54.305′ W

Air Temp: 16˚C (60˚F)

Water Temp: 12˚C (54˚F)

Ocean Depth: 30 m (100 ft.)

Relative Humidity: 81%

Wind Speed: 10 kts (12 mph)

Barometer: 1,013 hPa (1,013 mbar)

Science and Technology Log:

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Hydrographic Senior Survey Technician Clint Marcus is cataloguing all of the discreet hazards and objects by location and by photographic evidence that will be available for the new nautical charts once the survey is complete.

Uncovering potential dangers to navigation often requires more that acoustic equipment to adequately document the hazard.  Many hazards are in water that is shallow enough to potentially damage equipment if a boat were to be operating in that area and may also require special description to provide guidance for those trying to interpret the hazard through nautical charts and changing tides.  This is one of the key reasons so much planning must be placed into assigning survey areas determining the size and extent of polygons for mapping.  Depending on the complexity of the area’s structures, the polygon assignment will be adjusted to reasonably reflect what can be accomplished in one day by a single launch.  Near-shore objects may require a smaller boat to adequately access the shallow water to move in among multiple hazards.  This is where a smaller boat like the Fairweather’s skiff can play a role.  The skiff can be sent out to map where these near-shore hazards are using equipment that that will mark the object with a GPS coordinate to provide its location.  Additionally, a photograph of the hazard is taken in order to provide a greater reference to the extent of the object and what it looks like above or below the water.  This information is collected and catalogued; so, the resulting nautical chart will have detailed resources and references to existing nautical hazards.

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Ensign Pat Debroisse covers nautical hazards such as rocks and kelp indicated throughout a very shallow and hazardous inlet.

Nautical hazards are not the only feature found on charts.  Nautical charts also have a description of the ocean bottom at various points throughout the charts.  These points may indicate a rocky bottom or a bottom consisting of silt, sand, or mud.  This information can be important for local traffic in terms of boating and anchoring and other issues. In order to collect samples from the bottom, a launch boat drops a diving probe that consists of a steel trap door that collects and holds a specimen in a canister that can be brought up to the boat.  Once the sample is brought up to the boat, it is analyzed for rock size and texture along with other components such as shell material in order to assign a designation.  This information is collected and catalogued so that the resulting nautical chart update will include all of the detailed information for all nautical hazards within the survey area.

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Bottom samples are taken with a heavy steel torpedo-shaped probe that is designed to sink quickly, dive into the ocean bottom, clamp shut, and return a sample to the boat.  Credit Ensign Joseph Brinkley for the photo.

Personal Log:

Dear Mr. Cody,

The food on the cruise ship is great. They have all of our meals ready and waiting.  There are many people who prepare and serve the food to us to make our trip enjoyable.  (Dillion is one of my science students who went on an Alaska cruise with his family in May and will be corresponding with me about his experiences as I blog about my experiences on the Fairweather.)

Dear Dillion,

The food onboard the Fairweather is also very good.  Much of the work that they do happens so early in the morning that most never see it take place.  Our stewards take very good care of us by providing three meals a day, snacks, and grab bag lunches for all of our launches each day.  They need to start early in morning in order to get all of the bagged lunches for the launches prepared for leaving later that morning and breakfast. They start preparing sandwiches and soup for the launches at 5 AM and need to have breakfast ready by 7 AM; so, mornings are very busy for them.  A morning snack is often prepared shortly after breakfast for those on break followed by lunch and then an afternoon snack and finally dinner.  That is a lot of preparation, tear down, and clean up, and it all starts over the next day.  The steward department has a lot of experience in food preparation aiding them in meeting the daily demands of their careers while preparing delicious and nutritious food that the crew will enjoy.

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What are you doing at 5:15 in the morning?  Mornings are very busy for the steward department preparing lunches for the day’s hydrographic launches and breakfast for the entire crew.  From left to right, Chief Steward Frank Ford, Chief Cook Ace Burke, Second Cook Arlene Beahm, and Chief Cook Tyrone Baker.

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Chief Steward Frank Ford is preparing a delicious mid-morning snack for the crew.

Frank Ford is the chief steward. He has been in NOAA for six years.  Before joining NOAA he had attended culinary school and worked in food service for 30 years in the restaurant and hotel industry.  “I try to make meals that can remind everyone of a positive memory…comfort food,” Frank goes on to say, “Having good meals is part of having good morale on a ship.”  Frank and the others in the steward department must be flexible in the menu depending on produce availability onboard and available food stores as the mission progresses.

 

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Chief Cook Tyrone Baker helps prepare breakfast.

Tyrone Baker is the chief cook onboard. He has been in NOAA for 10 years and has 20 years of food service experience in the Navy.  Ace Burke has been with NOAA since 1991 and has served in many positions in deck and engineering and has been a steward for the last 15 years.  He came over from the NOAA ship Thomas Jefferson to help the steward department as a chief cook. Arlene Beahm attended chefs school in New Orleans.  She has been with NOAA for 1 ½ years and started out as a general vessel assistant onboard the Fairweather and is now a second cook.

 

Did You Know?

Relying on GPS to know where a point is in the survey area is not accurate enough.  It can be off by as much as 1/10 of a meter.  In order to increase the accuracy of where all the points charted on the new map, the Fairweather carries horizontal control base stations onboard.  These base stations are set up on a fixed known location and are used to compare to the GPS coordinate points.  Utilizing such stations improves the accuracy of all points with the survey from 1/10 of a meter of uncertainty to 1/100 of a meter or a centimeter.

Can You Guess What This Is?109_0609 (2)

A. an alidade  B. a sextant  C. an azimuth circle  D. a telescope

The answer will be provided in the next post!

(The answer to the question in the last post was D. a CTD.  A CTD or Conductivity, Temperature, and Depth sensor is needed for hydrographic surveys since the temperature and density of ocean water can alter how sound waves move through the water column. These properties must be accounted for when using acoustic technology to yield a very precise measurement of the ocean bottom.  The sensor is able to record depth by measuring the increase of pressure, the deeper the CTD sensor goes, the higher the pressure.  Using a combination of the Chen-Millero equation to relate pressure to depth and Snell’s Law to ray trace sound waves to the farthest extent of an acoustic swath, a vertical point below the water’s surface can be accurately measured.  Density is determined by conductivity, the greater the conductivity of the water sample running through the CTD, the greater the concentration of dissolved salt yielding a higher density.)

Kainoa Higgins: Mantas and Megalopae, June 28, 2014

NOAA Teacher at Sea
Kainoa Higgins
Aboard R/V Ocean Starr
June 18 – July 3, 2014

Mission: Juvenile Rockfish Survey
Geographical Area of Cruise: Northern California Current
Date: Saturday, June 28, 2014

Weather Data from the Bridge: Current Latitude: 45° 59.5’ N Current Longitude: 125° 02.1’ W Air Temperature:  12.7° Celsius Wind Speed: 15 knots Wind Direction: WSW Surface Water Temperature: 15.5 Celsius Weather conditions: Partly cloudy

Find our location in real time HERE!

Science and Technology Log:

Neuston Net and Manta Tow Today, the weather is pleasant but the sea seems more than restless. The show must go on! I step onto the open deck behind the wet lab just as Dr. Curtis Roegner, a fisheries biologist with NOAA, is placing a GoPro onto the end of an extensive net system.

Dungeness Crab – A Pacific Northwest Delight Photo Credit: http://www.smokeybay.com

While Curtis specializes in the biological aspects of oceanography, he is especially interested in the synthesis of the ocean system and how bio aspects relate to other physical and chemical parameters. He joins this cruise on the Ocean Starr as he continues a long-term study of distribution patterns of larval crabs. The species of focus: Cancer magister, the Dungeness crab; a table favorite throughout the Pacific Northwest.

While I have been known to eat my weight in “Dungies”, I realize that I know very little about their complex life cycle. We begin with “baby crabs”, or crab larvae. Once they hatch from their eggs, they quickly join the planktonic community and spend much of their 3-4 month developmental process adrift – at the mercy of the environmental forces that dictate the movement of the water and therefore, govern the journey of these young crustaceans. It has been generally assumed that all planktonic participants float wherever the waters take them. In that context, it makes sense that we have been finding large numbers of larvae miles offshore during our nighttime trawl sorting. Still, not all are swept out to sea. Every year millions make their way back into the shallows as they take their more familiar, benthic form which eventually grows large enough to find its way to a supermarket near you. The question is: How? How do these tiny critters avoid being carried beyond the point of no return? Is it luck? Or is there something in the evolutionary history of the Dungeness crab that has allowed it to adapt to such trying conditions?

Dungeness Crab Megalopae

“Dungie” babies

Curtis tells me about recent research that suggests that seeming “passive” plankton may actually have a lot more control of their fate than previously supposed.  By maneuvering vertically throughout the column they can quite dynamically affect their dispersal.  Behavioral adaptation may trigger vertical migration events that keep them within a particular region, playing the varied movement of the water to their advantage.  Curtis believes the answer to what determines Dungie abundance lies with with the Megalops, the final stage of the larva just prior to true “crab-hood”. By the end of this stage they will have made their way out of the planktonic community and into estuaries of the near shore zone.

Kainoa and Curtis

Dr. Curtis Roegner explains the importance of his study

This continued study is important in predictably marking the success or failure of a year’s class of crab recruitment. That is to say, the more Megalopae that return to a region, the better the promise of a strong catches for the crabbing industry – and a better chance for you and me to harvest a crab or two for our own table!

As Curtis and I discuss his research, he continues preparing his sampling equipment. The instrument looks similar to the plankton nets we use in marine science at SAMI only it’s about ten times longer and its “mouth” is entirely rectangular, unlike the circular nets I am used to using. I’ve heard the terms “manta”, “bongo” and “neuston” being tossed around lab and yet I am unable to discern one from the other. It’s time I got some answers!

Curtis explains that the Megalopae he wants to catch are members of the neuston, the collective term given to the community of organisms that inhabit the most surface layer of the water column. The Neuston net is named simply for its target. It occurs to me that a “plankton net” is a very general term and that they can come in all shapes and sizes. In addition, the mesh of the net can vary drastically in size; the mesh on our nets at school is roughly 80µm, while the mesh of this net is upwards of 300μm (1 µm or micrometre is equivalent to one millionth of a metre).

Manta tow & Neuston net

The manta body design for neuston sampling. A specialized plankton tow.

I’m still confused because I am fairly certain I have heard others refer to the tool by another name. Curtis explains that while any net intended to sample the surface layer of the water column may be referred to as a neuston net, this particular net had a modified body design which deserved a name of its own. The “manta” is a twin winged continuous flow surface tow used to sample the neuston while minimizing the wake disturbance associated with other models. The net does seem to eerily resemble the gaping mouth of a manta ray. These enormous rays glide effortlessly through the water filtering massive volumes of water and ingesting anything substantial found within. On calm days, our metallic imposter mimics such gracefulness. Today however, it rides awkwardly in the chop, jaggedly slicing and funneling the surface layer into its gut. It’s all starting to make sense. Not only is this a plankton net designed to sample plankton, it is also a plankton net designed to sample only the neuston layer of the planktonic community.   The modified body sitting on buoyed wings designed to cover a wider yet shallower layer at the top of the water column further specified the instrument; a neuston net towed via manta body design for optimized sampling. Got it.

Collected Plankton Sample

A filtered sample of various crustaceans collected from the neuston

After the tow is complete, Curtis dumps the cod end of the net into a sieve, showing me an array of critters including more than a dozen Megalopae! Two samples are frozen to ensure analysis back at the Hammond Lab in Astoria. There, Curtis will examine the developmental progress of the Megalopae in relation to the suite of data provided by the CTD at each testing site. This information, along with various other chemical and physical data will be cross-examined in hopes of finding correlation – and perhaps even causation – that make sense of the Dungeness crabs’ biological and developmental process.

Analysing CTD Data

Dr. Curtis Roegner looks for patterns relating crab Megalopae and CTD data

The CTD 

CTD

The CTD measures conductivity, temperature and depth among other auxiliary measurements

Fundamentally, a CTD is an oceanographic instrument intended to provide data on the conductivity, temperature and depth of a given body of water. The CTD is one of the most common and essential tools on board a research ship. Whether it’s Jason exploring benthic communities, Sam hunting jellies, or Curtis collecting crab larvae, all can benefit from the information the CTD kit and its ensemble of auxiliary components can provide about the quality of the water at a given test site. In general, the more information we collect with the CTD the better our ability to map various chemical and physical parameters throughout the ocean. Check out the TAScast below as I give a basic overview of and take a dive with the CTD and its accessories.  

 

 

Personal Log:

Just when I thought I was beginning to get the hang of it…. Hold on, I have to lie down. As I mentioned above, the seas have been a bit rougher and I’ve been going through a phase of not-feeling-so-hot for the first time this trip. It’s odd because we hit some rougher ocean right out of Eureka and it didn’t seem to faze me much. I stopped taking my motion sickness medicine a few days in, and though I’ve picked it back up just in case, I’m not entirely convinced it’s the only contributing factor. I think it has more to do with my transition onto the night shift and all the plankton sorting which requires lots of focus on tiny animals. The night before last was particularly challenging. In the lab, all of the papers, books and anything else not anchored down slid back and forth and my body felt as if it were on a giant swing set and seesaw all at once. In addition, each time I looked out the back door all I could see was water sloshing onto the deck through the very drainage holes through which it was intended to escape. I remember wondering why there were so many rolls of duct tape strapped to the table and why chairs were left on their side when not in use. Well, now I know. Earlier today we made a quick pit stop in Newport, Oregon – home of the Hatfield Marine Science Center as well as NOAA’s Marine Operations Center of the Pacific. In short, this is where NOAA’s Pacific fleet of vessels is housed and the home base to several members of my science team, including Chief Scientist, Ric Brodeur.

The NOAA Pacific Fleet

The NOAA Pacific fleet at rest in Newport, OR.

I remember the anticipation of seeing the R/V Ocean Starr, a former NOAA vessel, for the first time. Growing up in Hawai’i, I remember these enormous ships making cameo appearances offshore, complete with a satellite dome over the bridge, only imagining the importance of the work done aboard. Now here I was, walking amongst the giants I idolized as a kid – the difference being that my view was up close and personal from behind the guard gate, a member of their team. I’m totally psyched even though I attempt to pretend like I’ve been there before. As much as I could have spent all afternoon admiring, I needed to make the most of our two hour layover in the library uploading blog material. Unfortunately the satellite-based internet is incredibly finicky out at sea. It’s a first world problem and understandably a part of life at sea, I realize, but all the same, I apologize to all those anticipating regular updates. I continue to do the best I can. I can say, however, that the Hatfield Marine Science Center boasts a fantastic library. I look forward to exploring the rest of the facility upon my final return in a little over a week. ‘Till then, BACK TO SEA!

Louise Todd, CTD and Samples, September 25, 2013

NOAA Teacher at Sea
Louise Todd
Aboard NOAA Ship Oregon II
September 13 – 29, 2013

Mission: Shark and Red Snapper Bottom Longline Survey
Geographical Area of Cruise: Gulf of Mexico
Date: September 25, 2013

Weather Data from the Bridge:
Barometric Pressure: 1008.6mb
Sea Temperature: 28.3˚C
Air Temperature: 26.3˚C
Wind speed: 8.73knots

Science and Technology Log:

After we set the line, the CTD (Conductivity, Temperature, Depth) is deployed at each station.

CTD

CTD ready to be deployed

This instrument provides information a complete profile of the physical characteristics of the water column, including salinity, temperature and dissolved oxygen.  The CTD is deployed from the bow of the boat using a winch.

Deploying the CTD

Deploying the CTD

When it is first lowered in the water it calibrates at the surface for three minutes.  After it is calibrated it is lowered into the water until it reaches the bottom.  The CTD records data very quickly and provides valuable information about the station.  Conductivity is used to measure the salinity, the amount of salt dissolved in the water.  The CTD also measures the dissolved oxygen in the water.  Dissolved oxygen is an important reading as it reveals how much oxygen is available in that area.  The amount of oxygen available in the water indicates the amount of life this station could be capable of supporting.  Dissolved oxygen is affected by the temperature and salinity in an area.  Higher salinity and temperature result in lower dissolved oxygen levels.  Areas of very low dissolved oxygen, called hypoxia, result in dead zones.  NOAA monitors hypoxia in the Gulf of Mexico using data from CTDs.

The otoliths and gonads are taken from all of the commercially and recreationally important fish like Snapper, Grouper and Tilefish.  Otoliths are used to age fish.  Aging fish provides information on the population dynamics for those species.  The otoliths are “ear bones” of the fish and are located in their heads.  It takes careful work with a knife and tweezers to remove the otoliths.

Removing otoliths

Removing otoliths

Once the otoliths are removed, they are placed in small envelopes to be examined in the lab in Pascagoula, MS.  Otoliths have rings similar to growth rings in trees that have to be carefully counted under a microscope to determine the age of the fish.

Otolith

Otolith

The gonads (ovaries or testes) are removed and the reproductive stage of the fish is determined.  The weights of the gonads are also recorded.  Small samples of the gonads are taken in order for the histology to be examined in the lab.  Examining the gonads closely will confirm the reproductive stage of the fish.  Gathering information about the reproductive stage of the fish also helps with understanding the population dynamics of a species and aids in management decisions.

Personal Log:

Taking the otoliths out of the fish was harder than I anticipated, especially on the larger fish.  It takes some muscle to get through the bone!

Otolith

Otolith removed from a Red Snapper

We have had a few very busy haul backs today.  One haul back had over 50 sharks!  My favorite shark today was a Bull Shark.  We caught two today but were only able to get one into the cradle long enough to get measurements on it.  We tagged it and then watched her swim away!  I can’t believe we are halfway through my second week.  Time is flying by!  I can’t wait to see what is on the line tomorrow!

Did you Know?

Yellowedge Grouper are protogynous hermaphrodites.  They start their lives as females and transform into males as they age.  Yellowedge Grouper are the only species of grouper we have caught.

Animals Seen

Here are a few of the animals we’ve seen so far!

Tilefish

Tilefish (Photo credit Christine Seither)

Sandbar

Sandbar shark in the cradle

Red Snapper

Red Snapper (Photo credit Christine Seither)

Yellowedge Grouper

Yellowedge Grouper (Photo credit Christine Seither)

Rosalind Echols: Cool Science on the Ship and Final Reflections on My Rainier Adventure, July 30, 2013

NOAA Teacher at Sea
Rosalind Echols
Aboard NOAA Ship Rainier
July 8 — 25, 2013 

Mission: Hydrographic Survey
Geographical Area of Cruise: Shumagin Islands, Alaska
Date: July 30, 2013

Current Location: 54° 55.6’ N, 160° 10.2’ W

Weather on board: Broken skies with a visibility of 14 nautical miles, variable wind at 22 knots, Air temperature: 14.65°C, Sea temperature: 6.7°C, 2 foot swell, sea level pressure: 1022.72 mb

Science and Technology Log:

Sometimes in school you hear, “You’ll need this someday.” You have been skeptical, and (at times) rightfully so. But here on the Rainier, Avery and I encountered many areas in which what we learned in school has helped us to understand some of the ship operations.

How does a 234 ft. ship, like the Rainier, float?

If you take a large chunk of metal and drop it in the water, it will sink. And yet, here we are sailing on a large chunk of metal. How is that possible? This all has to do with the difference between density (the amount of mass or stuff contained within a chunk of a substance) and buoyancy (the tendency of an object to float). When you put an object in water, it pushes water out of the way. If the object pushes aside an amount of water with equal mass before it becomes fully submerged, it will float. Less dense objects typically float because it doesn’t take that much water to equal their mass, and so they can remain above the water line. The shape of a ship is designed to increase its buoyancy by displacing a greater quantity of water than it would as a solid substance. Because of all the empty space in the ship, by the time the ship has displaced a quantity of water with equal mass to the ship itself, the ship is still above water. As we add people, supplies, gasoline and so on to the ship, we ride lower. As evidenced by the sinking of numerous ships, when a ship springs a hole in the hull and water floods in, the buoyancy of the ship is severely compromised. To take precaution against this, the Rainier has several extra watertight doors that can be closed in case of an emergency. That way, the majority of the ship could be kept secure from the water and stay afloat.

How does a heavy ship like the Rainier stay balanced?

Another critical consideration is the balance of the ship. When the ship encounters the motion of the ocean, it tends to pitch and roll. Like a pendulum, the way in which it does this depends largely on the distance between the center of gravity of the ship (effectively the point at which the mass of the ship is centered) and the point about which it will roll. Ships are very carefully designed and loaded so that they maintain maximum stability.

Boat stability diagram

Boat stability diagram

Ballast is often added to the hulls of ships for the following reasons:

  • to help keep them balanced when there is not enough cargo weight
  • to increase stability when sailing in rough seas
  • to increase the draught of the ship allowing it to pass under bridges
  • to counteract a heavy upper deck like that of the Rainier, which itself contains 64, 000 pounds of launches.

Ballast comes in many forms and historically rocks, sandbags and pieces of heavy metal were used to lower a ship’s center of gravity, thus stabilizing it. Cargo ships, when filling up at port, would unload this ballast in exchange for the cargo to be transported.  For example, in the 1800s, the cobblestone streets of Savannah, Georgia were made with the abandoned ballast of ships. Today water is used as ballast, since it can be loaded and unloaded easier and faster. Most cargo ships contain several ballast tanks in the hull of the ship.

Cargo ship with several ballast tanks

Cargo ship with several ballast tanks

It is thought that the capsizing of the Cougar Ace cargo ship bound for the west coast of the US in 2006, was caused by a ballast problem during an open-sea transfer.  The ship was required to unload their ballast in international waters before entering US waters to prevent the transfer of invasive species carried by the stored water. The result of the Cougar Ace snafu: 4, 700 Mazdas scrapped and millions of dollars lost. Oops!

Couger Ace capsized in open ocean

Cougar Ace capsized in open ocean

Because the Rainier is not loading and unloading tons of cargo, they use a permanent ballast of steel rebar, which sits in the center of the lower hull. Another source of ballast is the 102, 441 gallons of diesel which is divided between many gas tanks that span the width and length of the ship on the port and starboard sides.  These tanks can be filled and emptied individually.  For stability purposes the Rainier must maintain 30% of fuel onboard, and according to the CO, the diesel level is usually way above 30% capacity. The manipulation of the individual diesel tank levels is more for “trimming” of the boat which essentially ensures a smoother ride for passengers.

Where does all the freshwater come from for a crew of 50?

If only humans could drink saltwater, voyages at sea would be much easier and many lives would have been saved. Unfortunately, salt water is three times saltier than human blood and would severely dehydrate the body upon consumption leading to health problems such as kidney failure, brain damage, seizures and even death.  So how can we utilize all this salt water that surrounds us for good use?  Well, to avoid carrying tons of fresh potable water aboard, most large ships use some type of desalination process to remove the salt from the water.  Desalination methods range from reverse osmosis to freeze thawing to distillation. The Rainier uses a distillation method which mimics the water cycle in nature: heated water evaporates into water vapor, leaving salts and impurities behind, condensing into liquid water as the temperature drops. This all is happening inside a closed system so the resulting freshwater can be kept.  To speed up this process, the pressure is lowered inside the desalinator so the water boils at a lower temperature.  Much of the energy needed to heat the water comes from the thermal energy or waste heat given off by nearby machines such as the boiler.

Desalinator in the Rainier engine room

Desalinator in the Rainier engine room

Distillation purifies 99% percent of the salt water and the remaining 1% of impurities are removed by a bromine filter.  The final step of the process is a bromine concentration and PH check to ensure the water is potable. The bromine should be about .5 ppm and the PH between 6.8-7.2.

Daily water quality log

Daily water quality log

Everyday the Rainer desalinates 2500 gallons of saltwater to be used for drinking, cleaning and showering. The toilets, however, use saltwater and if you are lucky like me, you can see flashes of light from bioluminescent plankton when flushing in darkness. It’s like a plankton discotec in the toilet!

How does the chicken cross the road when the road is moving?

The difference between a road map and a nautical chart is that a road map tells you which way to go and a nautical chart just tells you what’s out there and you design your course.  Thus, navigating on the ocean is not as simple as “turn left at the stop sign,” or “continue on for 100 miles”, like directions for cars often state. Imagine that the road beneath you was moving as you drove your car. In order to keep following your desired course, you would need to keep adjusting to the changes in the road. That’s a lot like what happens in a ship. If you want to drive due west, you can’t simply aim the ship in that direction. As you go, the ship gets pushed around by the wind, the currents, and the tides, almost as if you drove your car west and the road slid up to the north. Without compensating for this, you would end up many miles north of your desired location. If you have a north-going current, you have to account for this by making southward adjustments. In a physics class, we might talk about adding vectors, or directional motion; in this case, we are considering velocity vectors. When you add up the speed you are going in each direction, you end up with your actual speed and direction. In the ship we make adjustments so that our actual speed and direction are correct.

Which way to the North Pole?

Did you know that when you look at a compass, it doesn’t always tell you the direction of true north? True north is directly towards the North Pole, the center of the Earth’s axis of rotation which passes directly to the true south pole. However, compasses rely on the location of the magnetic pole which is offset somewhat.

Compass showing true north and magnetic north

Compass showing true north and magnetic north

The combination of the solid iron core and the liquid iron mantle of the Earth create a magnetic field that surrounds the Earth (and protects us from some really damaging effects of the sun). If you visualize the Earth like a bar magnet, magnetic north is located at an approximate position of 82.7°N 114.4°W, roughly in the middle of northern Canada. If you stood directly south of this point, your compass would point true north because true north and magnetic north would be on the same line of longitude. However, as you get farther away from this west or east, the North indicated by your compass is more and more offset.

The magnetic poles of the earth

The magnetic poles of the earth

Earth showing true and magnetic poles

Earth showing true and magnetic poles

Our navigational charts are made using “true” directions. Because of our location in Alaska, if we were steering by compass, we would have to offset all of our measurements by roughly 14° to account for the difference in true and magnetic north. Fortunately, due to the advent of GPS, it is much simpler to tell our true direction.

Why so much daylight and fog?

Every hour, the crew of the Rainier measures the air temperature, sea water temperature, atmospheric pressure, and relative humidity. Aside from keeping a record of weather conditions, this also allows the National Weather Service to provide a more accurate weather forecast for this geographical region by providing local data to plug into the weather prediction models.

Hourly weather log

Hourly weather log

Weather in the Shumagin Islands could be very different from that of the nearest permanent weather station, so this can be valuable information for mariners. In our time out here, we have experienced a lot of fog and cool temperatures (although the spectacular sunshine and sunsets of the past few days make that seem like a distant memory). One reason for this is our simultaneous proximity to a large land mass (Siberia, in far-east Russia) and the ocean. Cool air from the land collides with warm waters coming up from Japan, which often leads to fog.

Currents of the Pacific

Currents around Alaska

However, because we are pretty far north, we also experience a lot of daylight (although not the 24-hour cycles so often associated with Alaska). At this time of the year, even though the Earth is farther away from the sun that it is in our winter season, the axis of the Earth is tilted toward the sun, leading to more direct sunlight and longer hours of illumination.

Earth's orbit around the sun

Earth’s orbit around the sun

One slightly bizarre fact is that all of Alaska is on the same time zone, even though it is really large enough to span several time zones. Out in the west, that means that sunset is in fact much later than it otherwise should be. Our last few spectacular sunsets have all happened around 11pm and true darkness descends just past midnight.  I have on several occasions stayed up several hours past my bedtime fishing on the fantail or getting distracted wandering around the ship because it is still light out at 11pm!

Rosalind and Avery at sunset

Rosalind and Avery (with Van de Graaf generator hair) at sunset

Personal Log:

After roughly a week back on land, I have already been inundated with questions about life on the Rainier, the research we were doing, the other people I met, and so on. It occurs to me that as challenging as it was to embark on this journey and try to learn as much as possible in three weeks, perhaps the greater challenge is to convey the experience to friends, family, and most importantly, my students. How will I convey the sense of nervousness with which I first stepped from the skiff to land, trying not to fall in the frigid north Pacific? What will I do in my classroom to get my students as excited about learning about the ocean and diving into new experiences as I was on this trip? How will I continue to expand on the knowledge and experiences I have had during my time on the Rainier? At the moment, I do not have excellent answers to these questions, but I know that thinking about them will be one of the primary benefits of this extraordinary opportunity.

For the moment, I can say that I have deepened my understanding of both the value and the challenge of working in collaboration with others; the importance of bringing my own voice to my work as well as listening to that of others; and the extent to which new experiences that push me out of my comfort zone are incredibly important for my development as an individual. I genuinely hope that I can develop a classroom environment that enables this same learning process for my students, so that, like the science I discussed above, they aren’t doing things that they will, “need some day,” but doing things that they need now.

Finally, I will say that I am finishing this trip even more intrigued by the ocean, and its physical and biological processes, than I was before. When one of the survey techs declared, “This is so exciting! We are the first people ever to see the bottom of this part of the ocean!” she wasn’t exaggerating. Even after my time on the Rainier, I feel like I am only beginning to scratch the surface of all of the things I might learn about the ocean, and I can’t wait to explore these with my students. I look forward as well to the inevitable research that I will do to try to further solidify my understanding and appreciation of the world’s oceans.

I leave with fond memories of a truly unique 18 day voyage aboard the most productive coastal hydrographic survey platform in the world: her majesty, the NOAA Ship Rainier. Thank you lovely lady and thank you Rainier crew for making this Teacher at Sea adventure so magical!

The most striking sunset of our voyage.

The most striking sunset of our voyage.

Avery Marvin: Cool Science on the Ship and final Reflections of My Rainier Adventure, July 30, 2013

NOAA Teacher at Sea
Avery Marvin
Aboard NOAA Ship Rainier
July 8 — 25, 2013 

Mission: Hydrographic Survey
Geographical Area of Cruise: Shumagin Islands, Alaska
Date: July 30, 2013

Current Location: 54° 55.6’ N, 160° 10.2’ W

Weather on board: Broken skies with a visibility of 14 nautical miles, variable wind at 22 knots, Air temperature: 14.65°C, Sea temperature: 6.7°C, 2 foot swell, sea level pressure: 1022.72 mb

Science and Technology Log:

Sometimes in school you hear, “You’ll need this someday.” You have been skeptical, and (at times) rightfully so. But here on the Rainier, Rosalind and I encountered many areas in which what we learned in school has helped us to understand some of the ship operations.

How does a 234 ft. ship, like the Rainier, float?

If you take a large chunk of metal and drop it in the water, it will sink. And yet, here we are sailing on a large chunk of metal. How is that possible? This all has to do with the difference between density (the amount of mass or stuff contained within a chunk of a substance) and buoyancy (the tendency of an object to float). When you put an object in water, it pushes water out of the way. If the object pushes aside an amount of water with equal mass before it becomes fully submerged, it will float. Less dense objects typically float because it doesn’t take that much water to equal their mass, and so they can remain above the water line. The shape of a ship is designed to increase its buoyancy by displacing a greater quantity of water than it would as a solid substance. Because of all the empty space in the ship, by the time the ship has displaced a quantity of water with equal mass to the ship itself, the ship is still above water. As we add people, supplies, gasoline and so on to the ship, we ride lower. As evidenced by the sinking of numerous ships, when a ship springs a hole in the hull and water floods in, the buoyancy of the ship is severely compromised. To take precaution against this, the Rainier has several extra watertight doors that can be closed in case of an emergency. That way, the majority of the ship could be kept secure from the water and stay afloat.

How does a heavy ship like the Rainier stay balanced?

Another critical consideration is the balance of the ship. When the ship encounters the motion of the ocean, it tends to pitch and roll. Like a pendulum, the way in which it does this depends largely on the distance between the center of gravity of the ship (effectively the point at which the mass of the ship is centered) and the point about which it will roll. Ships are very carefully designed and loaded so that they maintain maximum stability.

Boat stability diagram

Boat stability diagram

Ballast is often added to the hulls of ships for the following reasons:

  • to help keep them balanced when there is not enough cargo weight
  • to increase stability when sailing in rough seas
  • to increase the draught of the ship allowing it to pass under bridges
  • to counteract a heavy upper deck like that of the Rainier, which itself contains 64, 000 pounds of launches.

Ballast comes in many forms and historically rocks, sandbags and pieces of heavy metal were used to lower a ship’s center of gravity, thus stabilizing it. Cargo ships, when filling up at port, would unload this ballast in exchange for the cargo to be transported.  For example, in the 1800s, the cobblestone streets of Savannah, Georgia were made with the abandoned ballast of ships. Today water is used as ballast, since it can be loaded and unloaded easier and faster. Most cargo ships contain several ballast tanks in the hull of the ship.

Cargo ship with several ballast tanks

Cargo ship with several ballast tanks

It is thought that the capsizing of the Cougar Ace cargo ship bound for the west coast of the US in 2006, was caused by a ballast problem during an open-sea transfer.  The ship was required to unload their ballast in international waters before entering US waters to prevent the transfer of invasive species carried by the stored water. The result of the Cougar Ace snafu: 4, 700 Mazdas scrapped and millions of dollars lost. Oops!

Couger Ace capsized in open ocean

Cougar Ace capsized in open ocean

Because the Rainier is not loading and unloading tons of cargo, they use a permanent ballast of steel rebar, which sits in the center of the lower hull. Another source of ballast is the 102, 441 gallons of diesel which is divided between many gas tanks that span the width and length of the ship on the port and starboard sides.  These tanks can be filled and emptied individually.  For stability purposes the Rainier must maintain 30% of fuel onboard, and according to the CO, the diesel level is usually way above 30% capacity. The manipulation of the individual diesel tank levels is more for “trimming” of the boat which essentially ensures a smoother ride for passengers.

Where does all the freshwater come from for a crew of 50?

If only humans could drink saltwater, voyages at sea would be much easier and many lives would have been saved. Unfortunately, salt water is three times saltier than human blood and would severely dehydrate the body upon consumption leading to health problems such as kidney failure, brain damage, seizures and even death.  So how can we utilize all this salt water that surrounds us for good use?  Well, to avoid carrying tons of fresh potable water aboard, most large ships use some type of desalination process to remove the salt from the water.  Desalination methods range from reverse osmosis to freeze thawing to distillation. The Rainier uses a distillation method which mimics the water cycle in nature: heated water evaporates into water vapor, leaving salts and impurities behind, condensing into liquid water as the temperature drops. This all is happening inside a closed system so the resulting freshwater can be kept.  To speed up this process, the pressure is lowered inside the desalinator so the water boils at a lower temperature.  Much of the energy needed to heat the water comes from the thermal energy or waste heat given off by nearby machines such as the boiler.

Desalinator in the Rainier engine room

Desalinator in the Rainier engine room

Distillation purifies 99% percent of the salt water and the remaining 1% of impurities are removed by a bromine filter.  The final step of the process is a bromine concentration and PH check to ensure the water is potable. The bromine should be about .5 ppm and the PH between 6.8-7.2.

Daily water quality log

Daily water quality log

Everyday the Rainer desalinates 2500 gallons of saltwater to be used for drinking, cleaning and showering. The toilets, however, use saltwater and if you are lucky like me, you can see flashes of light from bioluminescent plankton when flushing in darkness. It’s like a plankton discotec in the toilet!

How does the chicken cross the road when the road is moving?

The difference between a road map and a nautical chart is that a road map tells you which way to go and a nautical chart just tells you what’s out there and you design your course.  Thus, navigating on the ocean is not as simple as “turn left at the stop sign,” or “continue on for 100 miles”, like directions for cars often state. Imagine that the road beneath you was moving as you drove your car. In order to keep following your desired course, you would need to keep adjusting to the changes in the road. That’s a lot like what happens in a ship. If you want to drive due west, you can’t simply aim the ship in that direction. As you go, the ship gets pushed around by the wind, the currents, and the tides, almost as if you drove your car west and the road slid up to the north. Without compensating for this, you would end up many miles north of your desired location. If you have a north-going current, you have to account for this by making southward adjustments. In a physics class, we might talk about adding vectors, or directional motion; in this case, we are considering velocity vectors. When you add up the speed you are going in each direction, you end up with your actual speed and direction. In the ship we make adjustments so that our actual speed and direction are correct.

Which way to the North Pole?

Did you know that when you look at a compass, it doesn’t always tell you the direction of true north? True north is directly towards the North Pole, the center of the Earth’s axis of rotation which passes directly to the true south pole. However, compasses rely on the location of the magnetic pole which is offset somewhat.

Compass showing true north and magnetic north

Compass showing true north and magnetic north

The combination of the solid iron core and the liquid iron mantle of the Earth create a magnetic field that surrounds the Earth (and protects us from some really damaging effects of the sun). If you visualize the Earth like a bar magnet, magnetic north is located at an approximate position of 82.7°N 114.4°W, roughly in the middle of northern Canada. If you stood directly south of this point, your compass would point true north because true north and magnetic north would be on the same line of longitude. However, as you get farther away from this west or east, the North indicated by your compass is more and more offset.

The magnetic poles of the earth

The magnetic poles of the earth

Earth showing true and magnetic poles

Earth showing true and magnetic poles

Our navigational charts are made using “true” directions. Because of our location in Alaska, if we were steering by compass, we would have to offset all of our measurements by roughly 14° to account for the difference in true and magnetic north. Fortunately, due to the advent of GPS, it is much simpler to tell our true direction.

Why so much daylight and fog?

Every hour, the crew of the Rainier measures the air temperature, sea water temperature, atmospheric pressure, and relative humidity. Aside from keeping a record of weather conditions, this also allows the National Weather Service to provide a more accurate weather forecast for this geographical region by providing local data to plug into the weather prediction models.

Hourly weather log

Hourly weather log

Weather in the Shumagin Islands could be very different from that of the nearest permanent weather station, so this can be valuable information for mariners. In our time out here, we have experienced a lot of fog and cool temperatures (although the spectacular sunshine and sunsets of the past few days make that seem like a distant memory). One reason for this is our simultaneous proximity to a large land mass (Siberia, in far-east Russia) and the ocean. Cool air from the land collides with warm waters coming up from Japan, which often leads to fog.

Currents of the Pacific

Currents around Alaska

However, because we are pretty far north, we also experience a lot of daylight (although not the 24-hour cycles so often associated with Alaska). At this time of the year, even though the Earth is farther away from the sun that it is in our winter season, the axis of the Earth is tilted toward the sun, leading to more direct sunlight and longer hours of illumination.

Earth's orbit around the sun

Earth’s orbit around the sun

One slightly bizarre fact is that all of Alaska is on the same time zone, even though it is really large enough to span several time zones. Out in the west, that means that sunset is in fact much later than it otherwise should be. Our last few spectacular sunsets have all happened around 11pm and true darkness descends just past midnight.  I have on several occasions stayed up several hours past my bedtime fishing on the fantail or getting distracted wandering around the ship because it is still light out at 11pm!

Rosalind and Avery at sunset

Rosalind and Avery (with Van de Graaf generator hair) at sunset

Personal Log:

Well friends, I said a bittersweet goodbye to the Rainier and its incredible dynamic crew. I am sad to have left but am also excited to return home to the Oregon Coast to begin planning for this school year. I look forward to incorporating my newfound knowledge and unique experience at sea into the classroom.  I am still amazed at the breadth and diversity of information that I learned in just under 3 weeks. From learning how to steer the ship to acquiring and processing survey data to puffin reproduction, the list goes on. I never stopped asking questions or being curious.  And the Rainier crew was always there to graciously answer my questions.  I am grateful for all that they taught me and for the kindness and patience they consistently showed me.

When I asked Rick Brennan, the Commanding Officer, what he most enjoyed about his job, he responded “The people.” He said he enjoys seeing the personal and professional growth of individual crew members.  It is not hard to see that the Rainier crew is pretty amazing.  They are an extremely dedicated group of individuals whose passion for their profession supersedes living a “normal life”. Each one of them has an interesting story of how they got to the Rainier and many of them sacrifice family time and personal relationships to be aboard the ship for months at a time.

Beyond the scientific knowledge attained, I leave this ship with a few important life reminders.

1) Be patient with yourself, your own learning style, with others around you and the task at hand. Authentic science is messy and exhausting. Ship life attracts unique personalities.

2) Don’t forget about the big picture and why you are here in the first place. “Mowing the lawn” day in and day out can seem mundane but all of those data points together will compromise the updated nautical chart which will ensure safe mariner travel for a multitude of ships.

3) Teamwork is key to any complex operation. This not only means working together but always being willing to lend a helping hand and sharing your particular knowledge with fellow crew members.

4) Appreciate, observe and protect the natural beauty that surrounds us.  Cultivate this awareness in others. Our livelihood as a species depends on our interaction with the environment.

This is my second to last blog post. Stay tuned for an exciting last entry about my extended stay in Kodiak, Alaska (post Rainier) where I explored the unique cultural and historical facets of this vibrant fishing port. Note: This next post will involve bears, a seal skin kayak, a behind the scenes fish factory tour, orcas, reindeer sausage and fossils!

For now, I leave with fond memories of a truly unique 18 day voyage aboard the most productive coastal hydrographic survey platform in the world: her majesty, the Rainier. Thank you lovely lady and thank you Rainier crew for making this Teacher at Sea adventure so magical!

The most striking sunset of our voyage.

The most striking sunset of our voyage.

Julie Karre: A Day of No Fishing is Not a Day of Rest, July 27, 2013

NOAA Teacher at Sea
Julie Karre
Aboard NOAA Ship Oregon II
July 26 – August 8, 2013 

Mission: Shark and Red snapper Longline Survey
Geographical area of cruise: Gulf of Mexico, Atlantic
Date: July 27

Weather Data from the Bridge
W TO NW WINDS 5 TO 10 KNOTS
SEAS 1 TO 2 FT.

We departed Pascagoula yesterday with calm winds and steamy temperatures. Our team decided that with storms developing in and around the Gulf, it was best for us to head out to the Atlantic. So we’re all loaded in to hang out for a few days before the fishing begins.

Science and Technology Log

It would be easy to think of these traveling days as days of rest. But they are far from it. The ship’s crew and fishermen are hard at work each day keeping the ship running as it should. One of the tasks the fishing crew is responsible for is dealing with the rust that builds up on the ship. (Ok, seventh and eighth graders – why is rust such a problem for a ship?)

Because of the constant moisture, rust is a persistent problem on the ship, exacerbated by the salt. Whenever docked, the crew works tirelessly to get the ship into prime condition. Any of the deck equipment that can be removed gets taken to a workshop where it is sanded down to raw metal again and then galvanized. This increases the life of the equipment because galvanized steel doesn’t rust. That leaves all the parts that cannot be removed to be touched up piecemeal, as Lead Fisherman Chris Nichols said. On a day like today – calm sea, light wind, and no fishing – the guys set to work on designated areas of the ship. Once an area of rust is identified, the rust must be removed. After removing the rust and vacuuming up all the dust and particles, the area gets primer painted twice and then its topcoat. The end result is a nice clean look to the boat.

Opening on the starboard side of the ship getting its rust removal makeover.

Opening on the starboard side of the ship getting its rust removal makeover.

Removing rust from the railing on the starboard side.

Skilled Fisherman Mike Conway removing rust from the railing on the starboard side.

In addition to keeping the ship in tip-top shape, it is essential to make sure all of the equipment used during the survey works appropriately. Around 9:40am, the Oregon II stopped moving and deployed a CTD unit (conductivity, temperature, depth). These cylinder shaped units carry tanks that bring water samples back to the ship from designated depths while the sensors read the water for its temperature, depth, and salinity.

Alongside the crew hard at work, the science team is busy doing work on sharks that came with us from Pascagoula. According to scientist Lisa Jones, some of these sharks are from surveys done to collect sharks following the BP Oil Spill in the Gulf in 2010. Others are sharks that needed further identification and information from surveys like the one I am on. Each shark is weighed and measured, sexed, and then internal organs are removed for further analysis, tissue samples are taken, and the remains of the shark are thrown overboard to reenter the food chain.

Mike recording data as Lead Scientist Kristen Hannan dissects a Gulper Shark from a previous survey.

Scientist Mike Hendon recording data as Lead Scientist Kristin Hannan dissects a Gulper Shark from a previous survey.

During this down time I was treated to a visit to the bridge, where officers steer the ship, among other things. NOAA Corps Officer LTjg Brian Adornato was on duty and offered me a glimpse of the technology that keeps us headed in the right direction. The Oregon II has one propeller controlled by two engines, which are both running while we steam across the Gulf. The boat was on its version of autopilot while I was visiting, which means the navigational heading is programmed and the boat is steered on that heading automatically. Whether steered by hand or computers, the ship is rarely perfectly on its heading. (Come on seventh and eighth graders – what factors are also influencing the ship’s movement?)

All of the navigation equipment driving the Oregon II.

All of the navigation equipment driving the Oregon II.

The wind and water are factors in how close the ship’s course over ground is to its heading. The waves, currents, and wind are all pushing the ship.

Personal Log

While the ship is buzzing with work, there is also lots of time to sit and share stories. I feel very lucky to be aboard the Oregon II at all, but to be aboard with such welcoming and friendly people feels like I hit the jackpot.

I share a room with NOAA Corps Officer ENS Rachel Pryor. She is on duty from 8 am – noon and from 8 pm to midnight. During those hours it is her job to drive the ship. I am on duty from noon to midnight, but during these days prior to fishing, I have a lot of free time. I have been reading, taking pictures, and hanging out with the others. The sleeping on the ship is easy and comfortable. And the food is delicious. Chief Steward Walter Coghlan is an excellent cook.

Some of the things that have caught me off guard should make perfect sense to my lovely seventh and eighth graders, like why I had a blurry camera. (Ok, kiddos – the ship is an air-conditioned vessel kept at cool temperatures to relieve the crew and scientists from the heat of the Gulf. What happens if you keep your camera in your room and bring it out onto the hot deck to take pictures?)

CONDENSATION! The cool glass of the lens becomes immediately foggy with condensation from the high temperatures outside.

It only took me one time of making that mistake and missing some great pictures because of it to learn my lesson. I now keep my camera in a room closer to the outside temperature so it’s always ready to take pictures – like this one of me in my survival suit! I’m also thrilled I didn’t miss the sunset.

The Abandon Ship drill requires everyone on board to get into a survival suit. It's not easy.

The Abandon Ship drill requires everyone on board to get into a survival suit. It’s not easy. – Photo Credit: Skilled Fisherman Chuck Godwin.

A beautiful sunset on my first night out at sea.

A beautiful sunset on my first night out at sea.

The sunset glistening on the calm water the second night.

The sunset glistening on the calm water the second night.

Did You Know?

Fathoms are a unit of measurement commonly used to measure the depth of a body of water. One fathom is exactly six feet.

Animals Seen

Flying Fish

Pilot Whales

Avery Marvin: Sound Off! From Noise to Nautical Charts, July 22, 2013

NOAA Teacher at Sea
Avery Marvin
Aboard NOAA Ship Rainier (NOAA Ship Tracker)
July 8 — 25, 2013 

Mission: Hydrographic Survey
Geographical Area of Cruise: Shumagin Islands, Alaska
Date: July 22, 2013

Current Location: 54° 55.6’ N, 160° 10.2’ W

Weather on board: Broken skies with a visibility of 14 nautical miles, variable wind at 22 knots, Air temperature: 14.65°C, Sea temperature: 6.7°C, 2 foot swell, sea level pressure: 1022.72 mb

Science and Technology log:

Teamwork, safety first

Rainier motto, painted in the stern of the ship above the fantail, the rear lower outside deck where we have our safety meetings.

“Teamwork, Safety First”, is inscribed boldly on the Rainier stern rafter and after being aboard for more than 2 weeks, it is evident this motto is the first priority of the crew and this complex survey operation at hand.

Rainier launch

This is one of the survey launches that we use to gather our survey data. In this case, the launch is shown approaching the Rainier, getting ready to tie up.

It’s a rainy overcast morning here in SW Alaska and we are circled around the officers on the fantail for the daily safety meeting. Weather conditions, possible hazards, and the daily assignment for each launch are discussed. Per the instructions on the POD (Plan of the Day), handed out the previous evening, the crew then disperse to their assigned launches. The launches are then one-at-a-time lowered into the water by the fancy davit machinery and driven away by the coxswain to their specific “polygon” or survey area for the day. A polygon surveyed by a launch on average takes 2-3 hours at 6-8 knots to survey and usually is an area that is inaccessible by the ship. Many polygons make up one large area called a “sheet” which is under the direction of the “sheet manager”. Several sheets make up an entire survey project. Our hydrographic project in the Shumagins has 8 sheets and makes up a total of 314 square nautical miles.

Safety meeting

The CO, XO, and FOO lead the safety meeting for the day, discussing weather conditions, water conditions, and the assignments for each launch.

Shumagin Islands

This is a chart of the Shumagin Islands showing the 8 sheets (highlighted in green) that we are surveying.

Polygons

East side of Chernabura Island divided into survey “polygons”, each labeled with a letter or word. Notice how each polygon is a small subset of the larger sheet.

On board each launch we have a complex suite of computer systems: one manages the sonar, another manages the acquisition software, and the third records the inertial motion of the launch as it rocks around on the water (pitch, heave, roll). The acquisition system superimposes an image of the path of the launch and the swath of the sonar beam on top of a navigational chart within the polygon. Starting at one edge of the polygon, the coxswain drives in a straight a line (in a direction determined by the sheet manager), to the other end of the polygon, making sure there is some overlap at the boundaries of the swaths. He/she then works back in the other direction, once again making sure there is some overlap with the adjacent swath. We call this “mowing the lawn,” or “painting the floor” as these are visually analogous activities. Throughout the day, we pause to take CTD casts so that we have a sound velocity profile in each area that we are working.

Launches

Typical launch dispersal for a survey day. Launches are signified by “RA-number”. You can also see the location of our tide measurement station and GPS control station, both of which we use to correct our data for errors.

Mowing the lawn

This image shows the software tracking the path and swath of the launch (red boat shape) as it gathers data, driving back and forth in the polygon, or “mowing the lawn.” The darker blue shaded area shows overlap between the two swaths. The launch is approaching a “holiday”, or gap in the data, in an effort to fill it in.

You might be wondering, why the swath overlap? This is to correct for the outer sonar beams of the swath, which can scatter because of the increased distance between the sea floor and the sonar receiver below the hull of the boat. The swath overlap is just one of the many quality control checks built into the launch surveying process. Depending on the “ping rate”, or the number of signals we are able to send to the bottom each second, the speed of the boat can be adjusted.  The frequency of the sound wave can also be changed in accordance with the depth. Lower frequencies (200 khz) are used for deeper areas and higher frequencies (400 khz) are used for shallower areas.

Rosalind working the surveying computers in the launch

Rosalind working the surveying computers in the launch

Despite what might seem like mundane tasks, a day on board the launch is exhausting, given the extreme attention to detail by all crew members, troubleshooting various equipment malfunctions, and the often harsh weather conditions (i.e. fog, swells, cool temperatures) that are typical of southwest Alaska. The success of the ship’s mission depends on excellent communication and teamwork between the surveyors and the coxswain, who work closely together to maximize quality and efficiency of data collection. Rain or shine, work must get done.  But it doesn’t end there. When the launches arrive back at the ship, (usually around 4:30 pm), the crew will have a debrief of the day’s work with the FOO (field operations officer) and XO (executive officer). After dinner, the survey techs plunge head first (with a safety helmet of course) into the biggest mountain of data I have EVER witnessed in my life, otherwise known as “night processing”. We are talking gigabytes of data from each launch just for a days work.  It begins with the transferring of launch data from a portable hard drive to the computers in the plot room. This data is meticulously organized into various folders and files, all which adhere to a specific naming format. Once the transferring of data has finished, the “correction” process begins. That’s right, the data is not yet perfect and that’s because like any good science experiment, we must control for extraneous factors that could skew the depth data. These factors include tides, GPS location error, motion of the launch itself, and the sound velocity in the water column.

Plot room

Our chief surveyor works in the plot room cleaning and correcting data.

Data cleaning.

Data showing the consequences of the tide changing. The orange disjointed surface shows the data before it was adjusted for the tide changing. You can see how the edges between swaths (i.e. red and olive green) do not match up, even though they should be the same depth.

Sound speed artifact

This image shows the edge effects of changing sound speed in the water column. The edges of each swath “frown” because of refraction owing to changing density in the water column. This effect goes away once we factor in our CTD data and the sound speed profile.

In previous posts, I discussed how we correct for tides and the sound velocity. We also correct for the GPS location of the launch during a survey day, so that any specific data point is as precisely located as possible. Although GPS is fairly accurate, usually to within a few meters, we can get even more precise (within a few centimeters) by accounting for small satellite errors throughout the day. We do this by determining the location of a nearby object (our Horizontal Control, HorCon, Station) very precisely, and then tracking the reported position of this object throughout the day. Any error that is recorded for this station is likely also relevant for our launch locations, so we use this as the corrector. For example, if on July 21, 2013, at 3pm, the GPS location of our Bird Island HorCon station was reported 3cm north of its actual location, then our launches are also probably getting GPS locations 3cm too far north, so we will adjust all of our data accordingly. This is one of the many times we are thankful for our software. We also account for pitch, heave, and roll of the launch using the data from the inertial motion unit. That way, if the launch rolled sideways, and the center beam records a depth of 30 meters, we know to adjust this for the sideways tilt of the launch.

HorCon station

This shows the set up of our Horizontal Control and tide gauge station. The elevated rock position was chosen to maximize satellite visibility.

After all correctors have been applied (and a few software crashes weathered), the survey technicians then sort through all the data and clean out any “noise.” This noise represents sound reflections on sea life, air bubbles, or other items that are not part of the seafloor.  Refraction of sound waves, as mentioned in the last post, is caused by density changes in the water due to changes in the temperature, pressure, or salinity.

Dirty data

This shows sonar data with “noise”. The noise is the seemingly random dots above and below the primary surface. On the surface itself, you can see data from four different swaths, each in a different color. Notice the overlap between swaths and how well it appears to be matching up.

Cleaned surface

This shows sonar data after the “noise” has been cleaned out. Notice how all data now appears to match a sea floor contour.

Many of the above correctors are applied the same day the data is collected, so the sheet manager can have an up-to-date record of the project’s progress before doing final planning for data collection the next day. After a sheet has been fully surveyed and ALL correctors applied, the sheet manager will complete a “descriptive report”, which accompanies the data and explains any gaps in the sonar data (“holidays”) and/or other errors present. This report, along with the data, is sent to the Pacific Hydrographic Branch for post-processing, and in 1-2 years, we will have a corrected and updated navigational chart. During this time the data is reviewed for quality and adherence to hydrographic specifications and then is distilled into a cartographic product (nautical chart) consisting of points, lines, and areas.

Personal Log:

So I am going to hold off in talking about an animal that has recently fascinated me and instead devote this personal log to some cool things I have been doing on the ship.

Most recently I got to be the helmsman and steer the ship. This involved me following orders from the “conning officer” who told me various steering commands such as: “Left ten degrees rudder”, “steady on course 167°”, “ease 5° right”, “helm in auto” (auto-pilot). To acknowledge the command, I repeated what the conning officer said followed by “aye”. For example: “Left ten degrees rudder, aye” or “course 167°, aye”.  When the boat is actually on the course that was requested by the conning officer, I repeated the command with the word “steady”. For example: “Steady on course 167°”

Avery at the helm

Avery at the helm

You might be wondering why all of the commands involve degrees. Well that is because this ship is steered by the rudder, similar to how you manually steer a small sailboat.  So changing the angle of the rudder will change the direction of the ship.  To change this angle, you turn the steering wheel a desired amount of degrees beyond zero in the direction the conning officer instructed.  So if he said “right 5 degrees rudder”, I would turn the steering wheel right, and stop at the 5 hash mark.

Once the boat actually turns 5°, I will make sure I am at the correct “heading” or degree mark that the conning officer instructed.  A heading can be any number between 000-360 (where 000-deg = North, 045 = Northeast, 090 = East, etc.) as this boat can turn in a complete circle and be navigated in any direction.  (There is 360° in both a compass and a circle.)  Once I am steady at the correct heading, I will put the steering wheel back to 0° which means the rudder is completely straight and parallel with the boat. At this point the boat is going straight. If this were a car, you could just stay straight no problem.

But because this boat moves in water and is affected by ocean conditions such as swells, it is easily knocked off course of the heading. So as helmsman I am constantly making tiny adjustments with the steering wheel by a few degrees in either direction to maintain my heading.   This adjustment is done using the steering wheel if I am driving manual, or using a dial on the gear panel if the boat is in “auto” (auto-pilot). Because the ship rudder must “push water out of the way” in order to steer the boat, there is a delay between when I turn the steering wheel to when the ship actually moves that amount of degrees. This is not a car which turns instantaneously by the movement of axles.  So I need to account for that “lag time” as well as ocean conditions and the speed of the boat when turning the ship.  For example, if the boat is going slow (3 knots) and I need to turn quickly, I will have to use a greater rudder angle.  Throughout this process I have several digital screens that show me my current position and course, current heading and desired heading as well as other navigational aides.  When I was helmsman, I was closely monitored and assisted by Jason, a former Navy Chief Boatswain, who is one of the best helmsman on the ship.  To be a good navigator you need to know the fundamentals but you also need a lot of practice and exposure to various navigational situations.

Helm stand

Helm stand

Yesterday, Rosalind and I got to work on deck and help the Chief Boatswain with various deck tasks such as lowering the anchor and assisting with the davit to hoist the launches from their day of surveying out on the water.  Assisting with the job of lifting a 16,000 lb launch with 3 people aboard using the davit winch was by far the most exhilarating experience thus far on the ship. I handled the task with extreme caution. As with being a helmsman, there are many factors I must consider as a davit operator.  For example, if there is a significant swell, I need to be more aggressive with the davit movements to get the boat lifted fast to avoid any excessive swaying in mid-air. Most importantly, I must attentively follow the gestures of the deck boss below who is able to see the launch very clearly and is directing me on every davit movement.  Even an experienced davit operator like Jason, who probably can predict the next davit movement in his sleep, must never assume and then act. He ALWAYS follows the exact orders of the deck officer below because he never knows what they are seeing that he cannot from the above deck.  Overall, with Jason’s close attention and assistance, I think I did a good job of assisting with the davit. The boat made it safely aboard, and my heart returned to a normal beating pattern. 🙂

Operating the crane to get the davit ready to lift the launch out of the water

Getting the davit positioned and ready to lift the launch out of the water.

On a lighter note I learned how to play the good ole’ mariner pastime favorite, Cribbage. Rosalind (the other Teacher at Sea and my delightful roommate) taught me how to play. We had a cribbage tournament here aboard the ship in which about 12 people competed. I did not advance to the finals but had a lot of fun nonetheless.  I am looking forward to gaining more Cribbage strategies so I can be a more competitive player for future matches.

First round of Cribagge tournament

First round of Cribbage tournament

Just for fun:

An adorable sole I caught on the fantail of the Rainer (I released him/her)

An adorable sole I caught on the fantail of the Rainer (I released him/her). 🙂

Fun factoid: A fathom which is a maritime measurement equal to 6 feet, was originally based on the distance, fingertip to fingertip of a man’s outstretched arms. Fathom that!