NOAA Teacher at Sea
Onboard NOAA Ship Thomas Jefferson
September 2 – September 19, 2014
Mission: Hydrographic Survey
Geographical area of cruise: North Atlantic Ocean
Date: September 18, 2014 – Day #261
Location of ship (at 0626 while in transit back to Norfolk): 40o 18.864’ N, 73o 48.974’ W
Science and Technology Log
For two consecutive days, I had the opportunity to join the hydrographic surveyors on the ship’s launch, HSL 3101 (see my previous post about the ship’s launches), as they surveyed areas close to the shoreline with multibeam echo sounding. The shallow water areas are tricky and take much time and talent to navigate. I have been a part of the Thomas Jefferson surveys of the deeper water with its “mowing the lawn” technique (see previous post), but the launch does not have the luxury of always logging data along straight lines at great distance, especially along the rocky New England coast. Check out these photos of the Launch!
Here was the Plan of the Day (POD) for my first day on the Launch, Day #259:
|0730||HSL 3101 Safety Briefing|
|0800||Deploy HSL 3101|
|1730||Recover HSL 3101|
|2400||Ship Anchored near H12679|
I want to call your attention to the 0730 Safety Briefing. This meeting took place the same time every morning that the Launch went out (which goes out every day during a leg of a survey, unless the weather is extremely bad). Many items are discussed during the briefing. I found it interesting that the coxswain (the person of the launch, including navigation and steering) also completes an Operational Risk Management survey each morning that examines the status of people heading out on the Launch and the physical environment. The following categories are ranked on a scale of 0 to 10, with 0 = no risk and 10 = highest risk.
- Resources: boat and equipment, supervision, communication, support
- Environment: surf zone, remoteness, ice, rocks, traffic, shallow or uncharted water
- Team Selection: experience, training and familiarity
- Fitness: physical and mental
- Weather: effects on mission and safety
- Mission Complexity: new or experimental, restricts maneuverability
The scores in all of these categories are tallied up. If the score is between 0 and 23, the rating is a low risk, or “green,” and the mission is given a go-ahead. If the score is between 24 and 44, the rating is an “amber” with a warning to use extra caution. If the score is 45 to 60, then the rating indicates that there is a high risk with a “red” warning to not go out. But the final total is not the final decision. The XO (Executive Officer) radios the final score to the CO (Commanding Officer), and the CO has the final say whether the Launch goes out or not. On my first day with the Launch, we had a score of 23, with the highest individual scores of 5 for Environment and 5 for Team Selection (the rocky shoreline made sense for the higher score, and my presence as a first-timer on the Launch also raised the Team Selection score!). Another important part of the Safety Briefing is a review of the “boat sheet.” The people going out on the Launch review with the Field Operations Officer (FOO) the target areas for the Launch to visit and the data to acquire. Below is a slide show of the multi-page packet, prepared the evening before, that goes out with the team. This boat sheet is from my second day on the Launch, where our objective was to fill in holidays on previously-run survey lines (see my post on Holidays on the TJ).
Each day I spent on the Launch had a slightly different mission. On the first day, with two survey technicians, the coxswain, and myself, our goal was to obtain as much data about specific navigation hazards, as well as collect water depth data in shallower water than where the Thomas Jefferson can navigate. Our ship and Launch are required to survey to the 12-foot contour line, but we certainly had to be careful in this rocky area, as our multibeam echo sounder was sitting in the water approximately one foot lower than the hull of the Launch! (We had removed the side scan sonar from the Launch earlier in the week to give us more clearance to survey in this area.) We also ran the Launch at a speed no greater than 10 knots to maintain the quality of our data and to protect the instrument. On the second day, with one survey technician, the coxswain, and myself, you could probably tell from the boat sheets above that we spent the entire time filling in holidays in the data. On both days, we were slowed down a bit by a variety of “things in the way.” The photos below capture some of these obstructions.
Just like on the Thomas Jefferson, we needed to collect data to apply corrections for sound velocity in the water. NOAA doesn’t have MVPs on their launches (see more on the MVP), but instead use a similar instrument called a CTD. The “C” stands for conductivity, the “T” for temperature, and “D” for depth. When manually lowered over the side of the Launch, the CTD allows water to flow through the instrument, and data are collected as the instrument moves through the water column. See NOAA’s CTD page for more about a CTD and how it is used. View the slide show below for some images of the CTD going over the side of the Launch – and getting pulled back in by myself!
Getting to spend two days on the launch was the final, missing piece of my hydrographic survey experience on the Thomas Jefferson. I’m so glad I had the opportunity to head out and observe the work conducted by the launch. I found it fascinating that the reason the Launch spent an entire day going back to fill in holidays is because NOAA charts 100% of the coastal ocean floor. For example, a holiday may represent a 10-centimeter square gap in data – just 10 cm2! Literally, no stone is left unturned – or in this case, no piece of the coastal zone unmapped! My appreciation for the complexity of data gathering and processing for nautical charts just keeps growing and growing with every minute I spend on the TJ and now the Launch. I apparently missed a little excitement while out on the Launch, as the TJ traveled close to the RMS Queen Mary II, which was cruising through the area (from the Launch, we could only see it off in the distance).
But I’m fine with missing the Queen Mary II, because the coolest part of both days? I got to drive the launch!
OK GEOSC 040 students at Penn State Brandywine, here is your next round of questions. Please answer these questions online in ANGEL in the folder “Dr. G at Sea” in the link for Post #10.
- Is the Safety Briefing before the Launch goes out really necessary? Why/why not?
- What value is there in using a CTD while at sea? (*hint – be sure to check out the links I provided for additional information)
- NOAA makes sure that there are no gaps in their data in the coastal zone. This is in disagreement with Ocean Science Literacy Principle #7, don’t you agree? For your response to this question, write an exception to Principle #7 (let’s call it “Part G”) that says what we do know about the ocean, based upon what I’ve shared with you in these blog posts.
Random Ship Fact!
There are times when the launch is off surveying and the Thomas Jefferson does not have any lines to run. This does not mean the ship is staying put! One day, CDR Crocker decided to test the junior NOAA Corp officers with a man overboard drill. This was not a drill for the entire ship, but a challenge for those on the bridge to see if they could rescue “Oscar.” Oscar is thrown in the water by the CO, and the junior officers were tested to see how they navigate the ship and how long it takes to rescue Oscar (meaning, pull the floater out of the water). I happened to be on the bridge for the first two drills, which was fascinating to watch and to see the complexity involved in trying to orient the ship, keeping in mind the wind and currents. Oscar is now safely back on the ship, despite finding a way of “falling” back in the water several times, continuing his journey with us.
By the way, the name “Oscar” comes from the Morse code SOS distress signal, where the “O” stands for Oscar in the military phonetic alphabet. The Morse code communication system is a set of dots and dashes for numbers and each letter of the alphabet, and the letter “O” in Morse code is three long dashes. It is no coincidence that three long blasts of the ship’s horn is also the emergency signal for man overboard!