NOAA Teacher at Sea
Laura Grimm
Aboard NOAA Ship Thomas Jefferson
July 4 – July 22, 2022
Mission: Hydrographic Survey of Lake Erie
Geographic Area of Cruise: Lake Erie
Date: July 8, 2022
Weather Data from the Bridge
Latitude: 42ᵒ 11’3 N
Longitude: 080ᵒ 13’0 W
Sky Conditions: Few clouds
Wind Speed: 5 knots
Wind Direction: 208ᵒ SW
Lake Temperature: 21.8 ᵒC
Wave Height: <1 foot
Dry Bulb: 21.4 ᵒC
Wet Bulb: 20.3 ᵒC
Calculated Relative Humidity: 91%
Visibility: 10+ miles
Science and Technology Log
The Great Lakes system including all five lakes plus the St. Lawrence Seaway is one of the largest concentrations of freshwater on Earth. It carries billions of dollars of cargo to and from the Atlantic, has about 10,000 miles of coastline, hosts a $7 billion fishing industry, and heavily influences the climate in the region.
Vessels that sail on the Great Lakes are getting bigger and are super important to the US economy. For these ships to travel safely they need a certain depth of water. If the water is too shallow, they run aground and essentially get stuck. “Draft” is the vertical height between the waterline and the lowest point of the hull. It is how deep the hull can go, allowing the boat to float freely and without touching the bottom of the body of water such as the sea, ocean, or lake. NOAA Ship Thomas Jefferson has a draft of 14 feet + the equipment secured to the hull making the working draft 15.5 feet.
Those individuals navigating the ship use a huge variety of tools. One of them is a navigation map, also known as a nautical chart, on which has listed the water depth* at various locations. Just like you and your family might use a map to get from Cleveland to Boston, those navigating a ship use a chart to cross lakes and oceans.
(* Most of these numbers were made using ancient technology called “lead lines”. They are old data, but apparently, they are pretty accurate considering the technology hydrographers had at the time.)
A great amount of data on nautical charts of the Great Lakes is more than 50 years old, and only about 5 to 15 percent of the Great Lakes are mapped to modern standards.
One of NOAA’s missions for 2022 is to conduct several hydrographic survey missions on the Great Lakes.
“Missions” are broken down into field survey “projects”, which in 2022 include surveying Western Lake Michigan, the Thunder Bay National Marine Sanctuary in Western Lake Huron, the Detroit River (Michigan) between Lake St. Clair and Lake Erie, and the Cleveland area as well as the vicinity of South Bass Island and Presque Isle (Pennsylvania).
In collaboration between the Office of Coast Survey and the ship’s command, projects are broken down into “Sheets”. Survey ships will work at completing one sheet at a time. The number of sheets per project various greatly depending on a myriad of factors.
Sheets are further divided into “polygons”. Polygons are a more manageable “chunk” to work on . . . one polygon at a time.
So overall, the order of magnitude and size in each assignment from largest to smallest is thus: Mission, Project, Sheet, and finally Polygon.
When working on polygons, the survey is done either by the ship itself or by smaller boats called “Launches”. Launches work on the part of the polygon that is in shallow water &/or close to shore. NOAA Ship Thomas Jefferson has two launches, 2903 & 2904. These smaller boats are stowed onboard the main ship. The launch is a smaller vessel than the TJ, only 28 feet in length, with a 10-foot beam (width) and draft of 4 feet 8 inches. They are equipped with survey equipment similar to TJ.
So, today’s question is how do they get these smaller boats (launches) on and off the main ship? This is accomplished by an awesome hydraulic piece of machinery called a davit. Vestdavit, a company from Norway, makes the davits that are on the TJ. Taking the launches off or putting them back on the TJ is a team effort! It can be dangerous so everyone helping wears personal floatation devices (PFDs) and hardhats.
Notice that the launch in the previous pictures is secured to the davit by bow ropes, cables & hooks, ratchetted straps, and bumpers. Ships move around a lot. We don’t want the launches swinging and slamming into the davit. As mentioned previously, this piece of machinery uses hydraulics. Unlike the hydraulics we use in STEAM class, these use oil as the hydraulic fluid and not water. The hydraulic fluid used by NOAA is very environmentally friendly.
The following videos and pictures will show how the davit is used to capture and raise the launch from the water and back onto the TJ:
Step #1 – Get the launch close to the side of the ship where it will be stored. (2903 is stored on the starboard side (right side when looking toward the bow) of the ship. 2904 is stored on the port side (left side when looking toward the bow) of the ship.)
Step #2 – Get the lines ready and attach the painter line to the bow. The painter line is the white line in the video below.
Step #3 – Attach the davit clip to the hook on the bow.
Step #4 – Engaging the hydraulics will start to raise the boat out of the water. Notice that the large orange bumpers on the side of the launch help to protect the boat from bumping into the side of TJ. At this point, it is safe for the crew to disembark (get off) the launch.
Step #5 – The davit lifts the launch and places it in its hold or cradle.
Step #6 – Finally, secure the launch with a ratchetted straps or webs.
Unfortunately, they are having some difficulty with the davits aboard Thomas Jefferson. No launches will be deployed until they can get the issue resolved. In the meantime, data will continue to be taken using the Mulitbeam Echo Sounder (MBES) and other technology on Thomas Jefferson. I read recently that the CO (Commanding Officer) always puts personal safety before data acquisition. He and the crew really mean it!
Personal Log
Yesterday morning, I enjoyed watching the crew deploy both launches to do surveys close to the shore. It was choppy with 3-5 ft waves. I have not felt seasick on TJ, but choppy seas on a small boat would have made me revisit my breakfast. The launches came back in earlier than expected due to the rough water. It was exciting to see how efficient the crew was at deploying and recovering the launches . . . like a well-greased machine.
Operations Officer (OPS), Michelle, asked me to work with Operations Officer in Training (OPS IT), Sydney in the Plot Room. She will teach me all I need to learn about hydrographic data acquisition. (More on that in a later blog). There is so much to learn! If you are interested in math &/or science, you might want to look for a job at NOAA!
My time in the Plot Room was cut short because we had a fire drill followed immediately by an abandon ship drill. At school we have a variety of drills (fire, wind, lock down). Sometimes we take these drills for granted. We get lazy. Let me tell you! I was not prepared for the ship drills! Each drill is announced by the ship’s whistle. This is great and heard everywhere – however, it is worthless of you have not done your homework and learned what the whistles mean! I am guilty of not doing my homework! I was running around like a crazy person! Suddenly, I could not find my way around the ship! What was the drill? What did the whistles mean? What should I bring? Where should I go?
From now on, I WILL do my homework. I will be prepared, and I will no longer take drills at school for granted. They are important!
| Alarm | Signal | Where to report | What to bring |
| Fire or Other Emergency | Continuous sounding of general alarm or ship’s whistle | Main deck, port side, outside of the damage control pathway | Nothing, egress ASAP |
| Abandon Ship | 6 short blasts of ship’s whistle followed by one prolonged blast | 02 deck, starboard side, by raft #3 | Must wear PFD (life preserver), hat, long sleeves and carry survival suit (affectionately known as the Gumby Suit) |
| Man Overboard | 3 prolonged blasts of ship’s whistle | 02 deck, starboard side, watch aft | Nothing, egress ASAP |
For the little Dawgs . . .
Q: Where is Dewey today? Hint: it is usually underwater and helps move the boat.
A: Dewey is sitting on the propeller, also known as the prop. The motor of the boat spins the prop which makes the boat go forward, or if it is spun in the opposite direction, the boat goes backward.
One of the TJ’s engineers shared this picture of the Thomas Jefferson’s propeller. It was taken in the past when the ship was in “dry dock” undergoing repairs.
Well, that is all for now. I am assigned to be in the Plot Room again tomorrow morning from 6:00-8:00 am (0600-0800)*. I hope things go a bit more smoothly tomorrow. These wonderful scientists have so much knowledge + they do not mind me asking many, many questions = a great learning experience! Thank you, NOAA!
(*The ship runs on a 24 hour clock. Examples: 9:00 am = 0900. 3:00 pm = 1500. It’s easy once you get used to it. Also, I found out this morning that if you are scheduled for 0600, you really are supposed to show up at 0530. Oops! I try to keep a growth mindset in all I do!)
Thank you for all of the great information! I watched the TJ just outside the channel is Presque Isle from my boat a few different days. The boat itself is unique, and the technology is interesting.