Lynn Kurth: Time and Tide Wait For No Man, June 28, 2016


NOAA Teacher at Sea

Lynn M. Kurth

Aboard NOAA Ship Rainier

June 20-July 1, 2016

Mission: Hydrographic Survey

Geographical area of cruise:  Latitude:  57˚57.486 N   Longitude:  152˚55.539 W  (Whale Pass)

Date:  June 28, 2016

Weather Data from the Bridge
Sky:  Overcast
Visibility: 15 Nautical Miles
Wind Direction: 164
Wind Speed: 8 Knots
Sea Wave Height: 1 ft. (no swell)
Sea Water Temperature: 8.3° C (46.94° F)
Dry Temperature: 12.° C (53.6° F)
Barometric (Air) Pressure: 1019.6 mb

Science and Technology Log

The ocean supports many ecosystems which contain a diversity of living things ranging in size from tiny microbes to whales as long as 95 feet.  Despite the fact that I am working on a hydrographic ship, when out on a skiff or while in port, I have had the opportunity to view some of these ecosystems and a number of the species found in them.

While the Rainier was in port in Homer, I spent some time at the Kachemak Bay National Estuarine Research Reserve which, like other estuaries, is among the most productive ecosystems in the world.  An estuary, with accompanying wetlands, is where the freshwater from a river meets and mixes with the salt water of the sea.  However, there are some estuaries that are made entirely from freshwater.  These estuaries are special places along the Great Lakes where freshwater from a river, with very different chemical and physical characteristics compared to the water from the lake, mixes with the lake water.

Because estuaries, like the Kachemak Bay Estuary, are extremely fragile ecosystems with so many plants and animals that rely on them, in 1972 Congress created the National Estuarine Research Reserve System which protects more than one million estuarine acres.


Kachemak Bay National Estuarine Research Reserve

All estuaries, including the freshwater estuaries found on the Great Lakes, are affected by the changing tides.  Tides play an important part in the health of an estuary because they mix the water and are therefore are one of several factors that influence the properties (temperature, salinity, turbidity) of the water

Prior to my experience in Alaska, I had never realized what a vital role tides play in the life of living things, in a oceanic region.  Just as tides play an important role in the health and function of estuaries, they play a major role in the plants and animals I have seen and the hydrographic work being completed by the Rainier.  For example, the tides determine when and where the skiffs and multi beam launch boats will be deployed.  Between mean low tide and high tide the water depth can vary by as much as 12 feet and therefore low tide is the perfect time to send the skiffs out in to document the features (rocks, reefs, foul areas) of a specific area.

DSCN0069 (2)

Rock feature in Uganik Bay (actually “the foot” mentioned in previous blog) Notice tidal line, anything below the top of that line would be underwater at high tide!

In addition to being the perfect time to take note of near shore features, low tide also provides the perfect opportunity to see some amazing sea life!  I have seen a variety of species while working aboard the Rainier, including eagles, deer, starfish, dolphins, whales, seals, cormorants, sea gulls, sea otters and puffins.  Unfortunately, it has been difficult to capture quality photos of many of these species, but I have included some of my better photos of marine life in the area and information that the scientists aboard the Rainier have shared with me:

Tufted Puffins:  Tufted Puffins are some of the most common sea birds in Alaska.  They have wings that propel them under water and a large bill which sheds its outer layer in late summer.


Double Crested Cormorants:  Dark colored birds that dive for and eat fish, crabs, shrimp, aquatic plants, and other marine life.  The birds nest in colonies and can be found in many inland areas in the United States.  The cormorants range extends throughout the Great Lakes and they are frequently considered to be a nuisance because they gorge themselves on fish, possibly decimating local fish populations.


Cormorant colony with gulls

Pisaster Starfish:  The tidal areas are some of the favorite areas starfish like to inhabit because they have an abundance of clams, which the starfish love to feed on.  To do so, the starfish uses powerful little suction cups to pull open the clam’s shell.


Teacher at Sea Kurth with a starfish that was found during a shore lunch break while working on a skiff.


Starfish found in tidal zone

Glaucous-winged Gull:  The gulls are found along the coasts of Alaska and Washington State.  The average lifespan of Glaucous-winged Gull is approximately 15 years.


Glaucous-winged Gull watching the multi beam sonar boat

The hydrographic work in Uganik Bay continues even though there are moments to view the wildlife in the area.  I was part of the crew on board a boat equipped with multi beam sonar which returned to scan the “foot feature” meticulously mapped by the skiff.  During this process, the multi beam sonar is driven back and forth around the feature as close as the boat can safely get.  The multi beam does extend out to the sides of the boat which enables the sonar to produce an image to the left and right of the boat.  The sonar beam can reach out four times the depth of the water that the boat is working in.  For example, if we are working in six feet of water the multi beam will reach out a total of 24 feet across. Think of the sonar as if it was a beam coming from a flashlight, if you shine the light on the floor and hold the flashlight close to the floor, the beam will be small and intense.  On the other hand, if you hold the flashlight further from the floor the beam of light will cover a wider area but will not be as intense. The sonar’s coverage is similar, part of why working close to the shore is long and tedious work: in shallow water the multi beam does not cover a very wide area.


“The foot” feature (as discussed in previous blog) being scanned by multi beam sonar



Image of “the foot” after processing in lab. The rocks are the black areas that were not scanned by the multi beam sonar.

All Aboard!

I met Angelica on one of the first days aboard the Rainier and later spent some time with her, asking questions as she worked .  Angelica is very friendly, cheerful and a pleasure to talk with!  She graciously sat down with me for an interview when we were off shore of Kodiak, AK before returning to Uganik Bay.


Assistant Survey Technician Angelica Patyten works on processing data from the multi beam sonar

Tell us a little about yourself:

I’m Angelica Patyten originally from Sacramento, CA and happy to be a part of NOAA’s scientific mission!  I have always been very interested in marine science, especially marine biology, oceanography and somewhat interested in fisheries.  Ever since I was a little kid I’ve always been interested in whales and dolphins.  My cousin said that when I was really young I was always drawing whales on paper and I’d always be going to the library to check out books on marine life.  I remember one of the defining moments was when I was in grade school, we took a trip to see the dolphins and orca whales and I thought they were amazing creatures.

As far as hobbies, I love anything that has to do with water sports, like diving and kayaking.  I also want to learn how to surf or try paddle boarding as well.

How did you discover NOAA?:

I just kind of “stumbled upon” NOAA right after I had graduated from college and knew that I wanted to work in marine science.  I was googling different agencies and saw that NOAA allows you to volunteer on some of their vessels.  So, I ended up volunteering for two weeks aboard the NOAA ship Rueben Lasker and absolutely loved it.  When I returned home, I applied online for employment with NOAA and it was about six months before I heard from back from them.  It was at that point that they asked me if I wanted to work for them on one of their research vessels.  It really was all good timing!

What are your primary responsibilities when working on the ship? 

My responsibilities right now include the processing of the data that comes in from the multi beam sonar.  I basically take the data and use a computer program to apply different settings to produce the best image that I can with the sonar data that I’m given.

What do you love about your work with NOAA?

I love the scenery here in Alaska and the people I work with are awesome!  We become like a family because we spend a lot of time together.  Honestly, working aboard the Rainier is a perfect fit for me because I love to travel, the scenery is amazing and the people I work with are great!

Personal Log:

Geoffrey Chaucer wrote, “time and tide wait for no man.”  Chaucer’s words are so fitting for my time aboard the Rainier which is going so quickly and continues to revolve around the tides.

Susy Ellison, Aaargh Matey, How’s Your Number Sense? September 22, 2013

NOAA Teacher at Sea
Susy Ellison
Aboard NOAA Ship Rainier
September 9-26, 2013 

Mission:  Hydrographic Survey
Geographic Area:  Cold Bay, Alaska
Date:  September 22, 2013   

Weather:  current conditions from the bridge
GPS Location: 55o 15.190’ N   162o 38.035’ W
Temp: 8.6C
Wind Speed: 10 kts
Barometer: 1008.3mb
Visibility: 10 miles

You can also go to NOAA’s Shiptracker ( to see where we are and what weather conditions we are experiencing.

If you want a detailed report of weather in our area, check out this link and hover over Cold Bay:   

Science and Technology Log


Why am I sitting here?  What am I looking at?

Why am I sitting here? What’s out there?

 What would you think if you saw someone bundled in warm clothing, sitting in an office chair on a pier with a pair of binoculars, a watch, and a clipboard?  Are they counting waves? Counting birds?  Keeping track of the clouds or the wind speed?  In my case it was ‘none of the above’; I was watching a measuring stick, taking measurements every 6 minutes over a period of 3 hours.  Why would anyone want to sit in a chair on a pier and stare at a stick for 3 hours?

The answer, of course, is science! Now, this wasn’t just any sort of stick.  This tide staff was attached to an automatic tide gauge that the crew of the Rainier installed during their last visit to Cold Bay in August.  That gauge has been recording tidal data that is used during their hydrographic survey work.  But, as with any automatic data-gathering device, it is critical to field check its accuracy, both in measuring and reporting the data.  The gauge measures the depth of the water column at 6-minute intervals, using the pressure of the water column as a proxy for that depth (deeper water exerts a greater pressure on the subsurface opening of the gauge—for a more in-depth explanation, you can check out my blog from September 13th).  My job was to stare at the staff for a period of 1 minute every 6 minutes, and determine both the highest and lowest height of the water lapping at the markings on the stick.

This might sound easy, but it wasn’t quite so simple.  The wind was howling and the waves were bouncing—it took a little practice to make what I hoped was an accurate estimate of both the high mark and the low.  After each observation period I recorded these numbers on a spreadsheet and then spent the next few minutes watching the birds that were flying and landing on the water.  Then—back to the stick!  The tide was dropping with each observation and the winds died down enough to make it a little easier to read the high and low points on each successive 6 minute interval.  By the 10th observation I had it figured out!

NOAA Corps ENS Clark demonstrates proper form for tide gauge observation.

NOAA Corps ENS Clark demonstrates proper form for tide gauge observation.

Picture trying to read this from far away as the water bounces up and down the staff.

Picture trying to read this from far away as the water bounces up and down the staff.

The data I collected was matched against data from the tide gauge for that same time period.  I was pleased to see that my observations matched those of the gauge.  Apparently, both of ‘us’ are good observers of tidal changes.  Now I have one more skill to add to my resume!!

This graph compares my observations with that of the tide gauge.  What do we observe vs. what does a computer measure?

This graph compares my observations with that of the tide gauge. What do we observe vs. what does a computer measure?


It would be hard to find an aspect of life aboard the Rainier that doesn’t involve number sense or math.  This ship’s daily operations run like clockwork; breakfast from 0700-0800, Safety Meeting and deployment of the launches at 0800, lunch from 1130 to 1230, launches return at 1630, dinner from 1700 to 1800, etc.  Pretty simple numbers to deal with, but numbers, nonetheless.

That’s just the start of your applied math tour of the high seas. Maybe you have to figure out how much diesel fuel the ship has onboard.  Since the Rainier uses 20,000-40,000 gallons for each leg of its cruise, it would be pretty horrible to run out before you reached port.  The ship’s tanks can hold around 100,000 gallons of diesel and are usually filled to within 95% of that.  Unlike your car, there’s no fuel gauge on this ship.  So how do you figure out how much fuel is in the tank?  It’s time for some simple, yet essential math. First, you need to know the volume of the fuel tank.   Get out your math books and find that formula.  Then, you take what is called a ‘sounding’—you bang on the tank to determine the level of fuel.  Not too complicated, but certainly a skill that takes some practice.  So, now you know the total volume of the tank as well as the actual height of your fuel; if you figure out the volumes for each and do some subtraction, you can find out what percentage of your total fuel is still in the tank.

We might all be better at determining volume and percent if we had images of a fuel tank on the dashboards of our cars instead of a linear gauge reading ‘E’ to ‘F’! What about drinking water?  The Rainier uses a distillation system to create fresh water from seawater.  There are tanks down in the engine room where seawater is heated to the boiling point.  There’s a little more math and science in this process—the pressure in the distillation tank is lowered, to lower the boiling point (if you’ve ever camped at a high elevation you might notice that water boils at a lower temperature—your tea might not be quite as hot when it’s boiling) so the water doesn’t have to be heated quite so much to get it to boil.  This steam is captured in the upper portion of the distiller and cooled using cold seawater that flows through pipes.  The condensation from cooling is captured, filtered to remove any impurities, and distributed as fresh water to all onboard.  The ship uses around 2500 gallons of water each day.

Here's where all our fresh water is produced.  This distiller takes in seawater and, through boiling and condensation, produces fresh water.

Here’s where all our fresh water is produced. This distiller takes in seawater and, through boiling and condensation, produces fresh water.

If you’re running the galley it’s essential to calculate how much food you’ll need for each leg of the trip.  No one wants to do without their morning eggs if your multiplication is off and you ‘forget’ to buy a few dozen.  Taking a recipe that is designed to feed 8 people and ‘upsizing’ it for 48 people takes a bit of mathematical manipulation.  Just planning a menu for a three-week journey takes some mathematical thinking as you visualize the weeks, days, meals, and individual ingredients needed for those meals.  You have to factor in a few variables; which foods have the longest shelf life, when do you have to switch from fresh to frozen or to canned foods, how much food does the ‘average’ person eat, and what about all those people with food allergies or preferences?  While this might not sound quite as earth-shattering as using a detailed computer program to concatenate multiple data files, this is math that counts—especially when you’re feeding a boatload of hungry crew.

This is a glimpse of some of the supplies stored on the ship.

This is a glimpse of some of the supplies stored on the ship.

Don't forget to buy enough fruit and vegies!

Don’t forget to buy enough fruit and vegies!

Hmmm, what's in the freezer?

Hmmm, what’s in the freezer?

So now it’s time to consider the math used to pilot the ship.  Think about degrees in a compass bearing and the need to do some rapid mental math as you’re steering a 231-foot ship through some very tight spaces.  Quick—take a course of 340o, now look ahead and get ready to change your bearing to 28oRainier’s draft (how deep it sits in the water) is around 16’.  Will the channel be deep enough?  What if you’re traveling in a supertanker, one that might be over 400’ in diameter and have a draft up to 80’ deep?  If your ship is that big, you need to scale up on your mental math calculations as you’re searching out appropriate harbors and routes! What about tying up the ship when we’re in harbor? Did you remember to learn something about vectors before you stopped taking math classes?

When we were at port in Cold Bay, the winds were expected to increase in strength and to shift so that they would be coming out of the west.  Since the pier was oriented perpendicular to the predicted wind direction, our Chief Bo’ sun, Jim Kruger had to do some mental calculations of the angles needed to secure the ship to the pier and keep it from bouncing too much.  He doubled and even tripled some of the lines, taking into account how the winds might move the ship as well as the strength of each line.  It takes some stout lines to hold this ship; each 300 ft. line is 1” in diameter and has a tensile (breaking) strength of 164,000 lbs.    Vector angles were equally important as we pulled away from the pier in a 50-knot wind.  Just pulling up our gangway with a crane required some careful mental calculations of where to place lines to steady it as it rose through the air and was lifted onboard. If your mental math and visualization skills were wrong, you might be rewarded with a wildly swinging piece of metal.

Double (and triple) up the lines holding the ship to the pier.  Make sure the angles are right.

Double (and triple) up the lines holding the ship to the pier. Make sure the angles are right.

Hang tight to the gangway as it swings onboard.  Make sure you're holding it at the correct angle to compensate for the wind.

Hang tight to the gangway as it swings onboard. Make sure you’re holding it at the correct angle to compensate for the wind.

Strong winds--this digital anemometer records current wind speed in knots as well as the highest gust.

Strong winds–this digital anemometer records current wind speed in knots as well as the highest gust.

How about all that hydrographic data collection; there’s plenty of opportunity there for some pretty extreme mathematical calculations.  You might even wish you had taken a class in calculus—or a few classes!  But there are also plenty of times that some basic number sense and arithmetic come in mighty handy.  As I sat on the pier watching the tide gauge, one of the tasks I had to do was to calculate the average between high and low water marks on the tide staff.  Not such hard math, but it’s a good skill to be able to do averages in your head while your hands are getting cold and the wind is howling.  The tide gauge calculations were referenced to Coordinated Universal Time (UTC). This has been our world standard since 1972, and is referenced to the 0o meridian at Greenwich, England.  It is precisely measured using an atomic clock.  You might also hear it referred to as Zulu Time.  Even airplanes use this time designation.  This way, there is no ambiguity about whether you are in daylight savings or standard time, or your time zone.  When measuring tides or collecting information about water chemistry using the CTD, or calculating the launch’s daily gyrations, it is important to reference everything to the same time standard.  Since the Rainier is on RST (Rainier Standard Time), the calculation gets even more important because we are in the Alaska time zone, but have set our clocks back one more hour to give us more daylight working hours).

What's your time zone?  GMT stands for Greenwich Mean Time.  It is also the UTC time standard we use.

What’s your time zone? GMT stands for Greenwich Mean Time. It is also the UTC time standard we use.

Just in case your brain hasn’t been addled by all this talk of mathematics, there’s one more concept that might come in handy here on the high seas—a sine wave.  Huh?  Sine waves are a mathematical curve describing smooth repetitive oscillations.  Like…tides, sonar pulses, sunrise/sunset observations, or the music booming out of your iPod.

Tide charts show a predictable, repeatable sine wave pattern.

Tide charts show a predictable, repeatable sine wave pattern.

I even use math to calculate how long I should run on the elliptical trainer down in the ship’s exercise space.  If I set the resistance to 8, and use a cross training setting, it takes around 35 minutes to ‘run’ the equivalent of one slice of cake!

Here's some of the exercise equipment on the ship.

Here’s some of the exercise equipment on the ship.

35 minutes or one slice of pie--whichever comes first!

35 minutes or one slice of pie–whichever comes first!

Just in case you haven’t gotten the message—math is good.  Number sense is critical—even if you want to run off to sea!

Personal Log


The entire Cold Bay School fits into this truck!

The entire Cold Bay School fits into this truck!

I love a field trip.  There’s nothing like loading up in the bus and taking off in search of the great unknown.  While we were parked at the Cold Bay pier, we had a visit from the Cold Bay School.  The 8 students, plus their teacher and a classroom aide, came to check out the Rainier.  CO Rick Brennan gave them a tour, starting at the bridge, and ending with lunch in the wardroom.  Along the way, they learned about ships and ship life, NOAA, and the science of hydrography. Lunch was a real hit, since the kids all bring their own lunches to school.  Who wouldn’t like halibut tacos with all the fixings from the galley, or a peanut butter and jelly sandwich handmade by Commander Rick Brennan with a fresh cookie for dessert?

Cold Bay students check out some of the ship's BIG tools.

Cold Bay students check out some of the ship’s BIG tools.

I tagged along on the tour to talk with some of the kids and their teacher and to compare notes about schools.  While I always think of my school as small, with only 150 students, the school in Cold Bay is really small.  There are 8 students and they represent grades 1 through 7.  While the school is small, each student uses an iPad to access a wide variety of educational resources. It’s even better when that technology-based learning is supplemented by some hands-on field trip-based learning.  This was their second field trip of the week; they had spent a day with a wildlife biologist helping install a motion-sensitive camera in the Izembek Wildlife Refuge (

Future hydrographers head back to school.

Future hydrographers head back to school.


Where I live, in Colorado, we occasionally get snow days, when the roads are too dangerous to transport children to school.  Here at sea, we don’t worry too much about snow, but wind can create hazardous working conditions.  Yesterday we had what I would call a ‘Wind Day’; none of the survey launches went out.  The winds were gusting up to 50 knots, and were fairly steady at 30 knots.  That’s windy.  The surface of the bay was a froth of water, waves, and whitecaps.  Even the Black-legged Kittiwakes were having trouble flying!

Whitecaps all across the bay.  Definitely NOT a day to survey the sea floor.

Whitecaps all across the bay. Definitely NOT a day to survey the sea floor.

Certainly not the sort of day where you want to send out teams of hydrographers in 28 foot long launches.  While safety is paramount, data quality also suffers in such ‘bouncy’ seas.  As the launch bounces from side to side or from front to back, the sonar sends its pings far afield.  It becomes difficult or impossible to drive straight, overlapping lines as you ‘mow the lawn’ through your polygon (Wait, there’s another math term!) , and turning the craft requires timing and skill as you move through the rolling seas.  As the Rainier nears the end of its time at sea and in Cold Bay, each day becomes critical to achieve its charting goals—but there’s plenty of work to do on board on a day like this.