NOAA Teacher At Sea
Aboard NOAA Ship Thomas Jefferson
June 20- July 1, 2022
Mission: Hydrographic Survey
Geographic Area of Cruise: Lake Erie
Date: Sunday, June 26, 2022
Latitude: 41° 31.9′ N
Longitude: 81° 57.3′ 00 W
Altitude: 138 m
Weather Data from Bridge
Wind Speed: 8 kts
Surface Water Temperature: 23 °C
Air Temperature (Dry Bulb Temperature): 25 °C
Wet Bulb Temperature: 21 °C
Relative Humidity: 78 %
Barometric Pressure: 1014 mb
Science and Technology Log
Today, I am going to talk about anchoring the ship in Lake Erie, and some multibeam and side-scan images that NOAA Ship Thomas Jefferson obtained a while ago from different assignments.
The ship is mostly done scanning offshore portions of Lake Erie (2-7 nautical miles) from Lorain to Cleveland, OH, except near the shoreline. Waters near the shore are harder to scan for a ship like Thomas Jefferson because the water is shallower towards the coastline. Therefore, the ship decided to anchor closer inshore and launch its two boats to scan those areas. As I said before, the same multibeam and side-scan sonar beam technology is also in these boats. For the next couple of days while the ship is anchored, the boats will collect nearshore bathymetric data outside of Cleveland, OH.
The anchor is made of metal and is attached to the ship by a metal chain. First, it is important to decide where to anchor by looking at the chart. It’s usually preferred to anchor in sandy locations for stronger holding of the ship. However, most of the area we are surveying has a mud bottom, which is also okay for holding the anchor. The weight of the anchor is 3,500 lbs.! Once the ship was anchored, it swung around the chain due to the wind. The engine was off and we stayed there for about 4 days. Even though the engine was off, the generators were on. I will talk more about engines and generators in my next post.
Okay, let’s go back to multibeam and side-scan sonar. When the multibeam sonar scans to evaluate the depth of the water, the results can be shown in color schemes based on depth ranges. For example, during data acquisition we determined that 0-3.5 meters is black, 3.5- 5 meters is red, 5-10 is green and so on and so forth. This color coding is arbitrary as long as we have a legend at the bottom of the image that shows the depth of each color.
There was one interesting thing I learned today. Side-scan sonar can also show the presence of fish. During our data collection, we found schools of fish that are both small and big. How do we know the object we found is a school of fish? Well, often the shadow of an object in a sonar image can tell more information than the image of the object itself. If the object’s image has a shadow that is not attached to the object then it may be fish. Since the fish is swimming in the water, its shadow would look unattached in the image. We not only found a school of smaller fish, but also found a school of bigger fish. How do we know that they are big? The shadow can tell you! When looking at the image, we can identify individual fish as a dot, and the shadow can be measured to determine the size.
I am almost halfway through my expedition in Lake Erie. When I say I am learning, I do not mean that I am listening and observing what others say, and jotting down what I heard. I mean that I am hands on, doing what others do on the ship. My title on the small boat is “Crew-IT,” meaning crew in-training, and they teach me everything that I need to know. I was even on the deck (ship control center) navigating the ship for about 10 minutes. It wasn’t that complicated to navigate a 208 ft long NOAA ship after all!
I am not the only one who is training. There are many others, too: NOAA Corps officers, technicians, visitors, etc. The ship is not only completing its mission, but is constantly a training ground for others.
Okay, let me talk about my first time being sea sick. Except, I didn’t know what it was until somebody told me so the next day. So, I woke up earlier than usual that morning around 6 am. Because I had a full day boat assignment, I had to be fully ready. I packed a book to read, my camera, selfie stick and my notebook. I put on my sunscreen, and of course, my long pants. After eating my scrambled eggs with light roasted coffee, I quickly went down to my state room to brush my teeth to make sure I was on time for the 8 am safety briefing in the survey room. A safety briefing happens every day the small boats go out. We go over what work needs to be done for the day (general overview), what the weather will be like, and what the following days will look like. It takes about 15 minutes. At 8:15 am, we put on our safety gear (always confused whether to wear a crash helmet or hard hat), and lined up to be boarded. In about 10 minutes, we were on the boat, did routine safety checks, and started to survey. The weather was so hot and the bugs were of course in full bloom. Besides the hot “bug-gy” weather, the Lake was churning so bad that I couldn’t stand still. I had to either sit or stand while holding onto something. On that day, we were out until 7 pm. When we got back on the ship, I was so hungry but also so tired that I could not eat much. When people are late for the dinner which is eaten between 4:30pm to 5:30 pm, you make your orders before you leave for the boat, and they prepare your plate and put it in the fridge. I couldn’t eat anything that I ordered. Instead I ate an apple and went straight to bed.
I started to have a headache that I knew would eventually turn into a migraine. It was 10 pm, and my headache turned into a migraine. My migraine was so bad that my lids became so heavy that I could not open it. I was constantly turning in the bed, thinking that it would eventually go away once I slept. Nope! Nothing worked. I woke around 2 in the morning, took a shower and decided to take some ibuprofen. The medicine kicked in quickly and the next thing I remember was waking up at 7:30 am. I talked to my friend Justin that morning about what happened to me last night. He said that some people experience sea sickness in the form of a headache and suggested that I take the seasick medicine and eat a good, solid breakfast next time. I guess this is what I am going to do from now on when I have a boat assignment!
Did you know?
- NOAA Ship Thomas Jefferson is holding about 130,000 gallons of fuel which could last about 45 days. The ship has 33 tanks across the ship that includes fuel, drinking water, sewage, dirty water, etc.
- There is a “speed limit” on waterways? For example; Canada allows speed limit of 10 knots (11.5 miles/18.5 kilometers) in areas where the North Atlantic right whale have been reported in Gulf of Saint Lawrence which connects the Great Lakes to the Atlantic Ocean. The North Atlantic right whale, which is much larger than a humpback or a gray whale, is one of the most endangered whale species. More information about the species can be found here. Lake Erie doesn’t have speed regulation on open water unless there is a violation of marine laws or criminal activity.