survey launch – Page 22 – NOAA Teacher at Sea Blog

June 2, 2005March 18, 2021

Christy Garvin, June 2, 2005

NOAA Teacher at Sea
Christy Garvin
Onboard NOAA Ship Rainier
June 1 – 8, 2005

Mission: Hydrographic Survey
Geographical Area: Aleutian Islands, AK
Date: June 2, 2005

Weather from the Bridge

Latitude: 56 deg 59 min N
Longitude: 135 deg 17 min W
Visibility:12 nautical miles
Wind Direction: 275 deg
Wind Speed: 10 kts
Sea Wave Height: 1-2 ft
Swell Wave Height: 0 ft (we are in a protected bay)
Sea Water Temperature: 54deg F
Sea Level Pressure: 1016 mb

Science and Technology Log

Each evening aboard the RAINIER a POD, or plan of the day, is posted to inform all hands of the work scheduled for the following day. The POD for today, Thursday, June 2, showed that work would officially begin at 0800. Two launches were to be deployed in order to run survey lines; I was assigned to launch RA4 working near Sitka and off Baranof Island. Running survey lines is one of the most important tasks accomplished by the RAINIER. Since the ship’s scientific mission is hydrography, or charting of the ocean floor, the running of these lines is a major part of accomplishing that task.

Before the launches can actually run survey lines, there is a lot of preparation that takes place behind the scenes in the plotting room. Here, each area to be surveyed is subdivided into smaller plots and placed on survey sheets to make large areas more manageable. Then, a survey technician pulls existing nautical charts of the area and uses previously obtained depth information to determine where and how far apart to space the survey lines. In order to ensure 100% coverage of the ocean floor to the 8-meter mark, survey techs multiply the depth in fathoms (a fathom is 6 ft) by 5 to calculate the meters of line spacing. For example, if a launch is working in an area that is 7 fathoms deep, then the amount of space between the survey lines in that area would be 35 meters apart. The closest any lines are drawn is 25 meters apart.

Once the distance between lines has been established, the survey tech draws the lines on a map of the area. Lines are drawn parallel near the shoreline since close lines are necessary to achieve 100% coverage. Further from the shore, lines can be drawn in any direction, but they are usually drawn parallel to each other for ease in running the lines. These maps are taken out on the launches and entered into a specialized computer program that helps the launch find and follow the survey lines that have been drawn.

Personal Log

One of my favorite activities today was having the chance to drive the launch during a man overboard drill. I’m sure the life preserver in the water (our man overboard) breathed a huge sigh of relief that it wasn’t run over by the crazy coxswain (driver) at the helm.

Question of the day: What is a CTD?

Previous question of the day: What is hydrography and why is it necessary? Answer: Hydrography is the charting of the ocean floor. It is necessary because many ships use the information on the charts to ensure safe passage through narrow or shallow channels. Many of the old charts contain data that is very old or that was obtained by unreliable methods. It is important that charts are updated so that ships are able to pass through these areas safely.

June 1, 2005March 18, 2021

Christy Garvin, June 1, 2005

NOAA Teacher at Sea
Christy Garvin
Onboard NOAA Ship Rainier
June 1 – 8, 2005

Mission: Hydrographic Survey
Geographical Area: Aleutian Islands, AK
Date: June 1, 2005

Weather from the Bridge

Latitude: 56 deg 59 min N
Longitude: 135 deg 17 min W
Visibility: 12 nautical miles
Wind Direction: 285 deg
Wind Speed: 15 kts
Sea Wave Height: 1-2 ft
Swell Wave Height: 0 ft (we are in a protected bay)
Sea Water Temperature: 51deg F
Sea Level Pressure: 1022.5 mb

Science and Technology Log

Due to the Memorial Day weekend, today was the RAINIER’s first operational day since I arrived in Sitka, Alaska. Sitka is located off the western coast of Baranof Island and is surrounded by snow-covered mountains. The weather has been sunny with temperatures around 55 deg F. Currently, the RAINIER is anchored in the Aleutkina Bay, which is just south of Sitka.

Because several interns and new hands joined the crew for this leg of the journey, the CO, or Commanding Officer, declared today a stand down day. Basically, this meant that normal work operations were suspended so that the entire day could be devoted to training. A large part of our training was concerned with the deployment and recovery of small boats called launches.

The launches are stored on a system called the gravity falls davit. The system was originally designed for emergency boat deployment and is capable of working without any electricity; by lifting a lever and removing a small pin, the weight of the boat will cause the davit to slide down the track and drop the boat in the water. Although this works well in emergency situations, it causes a great amount of stress and strain on the equipment. Therefore, this method is not used for the daily deployment of the launches. Instead, a somewhat more complicated process requiring a team of ten or more people is used to safely put the boats in and out of the water.

The first step in deploying the boats is to unplug the boats from the main ship and loosen the gripes that secure the boat. Once the boat is no longer constrained, a team of four people standing on the deck below grabs ropes called frapping lines and helps stabilize the boat as it is lowered down to the deck level by a controller allowing the davit to slowly descend. Once the launch has reached the main deck level, a survey team boards the launch with all of their equipment.

At that point, one member of the survey team sits on the bow of the boat while another stands on the stern. Their job is to help detach the chain falls (a hook with an attached shackle) from the padeyes (a horseshoe shaped attachment bolted to the deck). This detachment occurs after the boat is slowly lowered into the water by a controller using a winch drum. Throughout the entire process, the boat is continually stabilized by the four linesmen who provide or remove slack from the frapping lines. The deck crew and survey teams have practiced this process many times, and the process is quick and efficient when run by an experienced crew.

However, it was much less graceful as all of the new hands took their turns on deck; ropes ended up in the water, the launches bumped the ship a few times, and hooks didn’t quite catch the padeyes; but by the end of the day all of the new hands were feeling much more confident in deployment and recovery of launches. It was an excellent opportunity to learn and practice new skills that will be used each day as survey teams are sent forth to accomplish the hydrography mission of the RAINIER.

Personal Log

I really enjoyed learning how to tie different types of knots and handle line today. Working as a linesman is very intense because someone could be seriously injured if you fail to do your job properly. The teamwork aspect is so important to safety as the launches are deployed, and I am having a great time actually being involved in the procedures that take place on the ship.

Question of the day: What is hydrography and why is it necessary?

July 11, 2004March 18, 2021

Leyf Peirce, July 11, 2004

NOAA Teacher at Sea
Leyf Peirce
Onboard NOAA Ship Rainier
July 6 – 15, 2004

Mission: Hydrographic Survey
Geographical Area: Eastern Aleutian Islands, Alaska
Date: July 11, 2004

Time: 21:00
Latitude: N 55°17.27
Longitude: W 160°32.16
Visibility: 4 nm
Wind direction: 095
Wind speed: 10 knots
Sea wave height: 0 – 1 foot
Swell wave height: —
Sea water temperature: 10.6 °C
Sea level pressure: 1017.0 mb
Air temperature: 12.8 °C
Cloud cover: 4/8

Science and Technology Log

Today was my second day aboard a launch boat. With SS Foye, ST Taylor, and ENS Samuelson, we continued to follow lines to chart the ocean floor just south of Egg Island. Today we were on launch boat 5, and luckily everything was working great! We were working with the Reson 8101 again. It should be noted that in previous journal entries I have been misnaming some of the equipment used. Today, I finally got the nomenclature correct. Here are the basics:

ELAC multibeam system is used for deep water, with best resolution over 30 meters
There are two shallow water mulitbeam (SWMB) systems:
1. Reson 8125 is used with a higher frequency and has better resolution in depths of 0 – 30 meters
2. Reson 8101 is used for “middle depths” of 0 –120 meters (mostly 30 –120 meters)

I also learned a lot more about how to use the software aboard the ship while we are taking data. For the Reson 8125 and Reson 8101, there are three computers aboard the ship that can talk to each other. Two are located in the cabin and one is located on the deck. One computer in the cabin is used primarily to navigate; the old charts are downloaded onto this computer and the lines on which we need to steer the boat (the lines for mowing the lawn) are superimposed on this chart. This computer is not only hooked up to the computer that gathers data, but is also connected to a computer that is mounted on the console so the captain can see where he or she needs to go. The navigational computer in the cabin is also directly hooked up to the other computer in the cabin. This second cabin computer is connected to the actual multibeam echo scanner system that is mounted to the hull of the ship. When instructed to do so, the second cabin computer can record the data from this system. One of the researchers uses the navigational computer to tell the second computer when to start and stop recording the data. Because the second computer is hooked up to the multibeam system, it also is used to control the parameters of this system, including filters, range, frequency of “pings”, and power. There are several different screens within the program used to control all of this, including a profile screen, which actually shows the profile of the ocean floor, a pitch/roll/heave screen to record that the POS/MV (the positioning device also hooked up to this computer that integrates with the data correcting for the gyration of the ship and it’s position), and a control screen. There are several other screens which can be displayed on this computer, however these listed here are the most important to monitor while gathering data. The power of the multibeam system can be monitored and altered according to depth and profile of the floor; if you want the device to “listen to the pings better”, you increase the power, and however, this also decreases resolution. You would want to do this in greater depths. You can also manually control the depth filter for the data. In order to do this, you change the range of the depths the multibeam system is looking for. This in turn changes the width of the footprint left by the data and thus the resolution. By doing this as you gather data, you are eliminating possible outlying points before ever having them recorded and you are allowing for better resolution at shallower depths. This makes the data processing and cleansing easier, yet it requires constant attention and anticipation while gathering data.

While this technology works relatively well in the field, it is still very expensive and time consuming. A possible design project for my students would be to analyze the existing system and brainstorm ideas for improvement. This would even include researching other systems used internationally.

Personal Log

Today was yet another beautiful day once the fog lifted by mid morning. I am still enchanted by the concept of conducting research on a boat all day—it seems like a job I would love to pursue! Not only are you contributing to society, but you get to see wonderful sights—today we saw a bald eagle, lots of puffin, and two sea lions! I cannot help but laugh at the puffin, though. They eat so much and have such little wings and huge hearts that they try with all their might to fly, but they only become air born with the nudge of a wave. And even then they only maintain an altitude of about 6 inches before they crash into another wave. They are both very amusing and very inspiring. I keep thinking that they are thinking “I think I can, I think I can, Never give up!” With so many sights and things going on both on and off the research vessel, I was not at all disappointed when we were radioed that we were going to spend an extra hour collecting data because the weather was so good (slightly chilly, but the sun was out). When we returned I learned how to download the data to the computers aboard the RAINIER, and then I saw the beginning steps for processing this data. I can’t wait to learn more tomorrow!

Question of the Day: A design problem: a gyrocompass is used to determine bearing and relies on electricity (it has an internal electromagnet). The gyrocompass on the bridge looks like this:

Notice that the angles visible here are 70 ° and 90 °, a difference of 20 °. However, this 20 ° difference is spread over what is actually about 100 °. How, then, does the gyrocompass span the full 360 °?

July 10, 2004March 18, 2021

Leyf Peirce, July 10, 2004

NOAA Teacher at Sea
Leyf Peirce
Onboard NOAA Ship Rainier
July 6 – 15, 2004

Mission: Hydrographic Survey
Geographical Area: Eastern Aleutian Islands, Alaska
Date: July 10, 2004

Time: 18:00
Latitude: N 55°17.29
Longitude: W 160°32.13
Visibility: 6 nm
Wind direction: 110
Wind speed: 12 knots
Sea wave height: 0 – 1 foot
Swell wave height: —
Sea water temperature: 10.6 °C
Sea level pressure: 1016.3 mb
Air temperature: 13.3 °C
Cloud cover: 3/8

Science and Technology Log

Today was the first day we launched the survey boats. I was assigned to a boat with SS Foye, ENS Welton, and ENS Samuelson. A very interesting and eventful day, the best way to describe it is with a timeline:

08:00 board 5 boat with SS Foye, ENS Welton, and ENS Samuelson; Lt. Slover (the FOO—Fieldwork Operations Officer) came aboard for about 20 minutes to run tests on the Reson 80101 multibeam echo sounding equipment we are using (soon dropped Lt. Slover back at the Rainier); NOTE: Reson 80101 is used primarily for shallower water, for it has better resolution at depths less than 75 meters

08:45 arrived at our first way point near Halfway Rock; took first cast with the CTD (testing for conductivity, temperature and depth—all things that factor into velocity speed profile) and found an average depth of about 65 meters

09:00 started doing lines (mowing the lawn pattern) around Halfway Rock; after about 3 lines, Lt. Slover called us back in because the data he had taken did not process correctly—the new programs aboard the ship were not working as well as they had thought

11:25 board the RAINIER while FOO checked our equipment; turned out we had to switch to 6 boat—including downloading new maps and figuring out a new system

11:45 board launches 6 boats and sets out for new set of lines at deeper water than the morning; this boat uses the ELAC multibeam systems which are better for deeper waters (up to 400 meters)

12:00 arrived at new line destination (lat: N 55/14/54, long: W 160/27/43) and ate lunch before doing our CTD cast

12:30 conducted first CTD cast, but computer messed up, so had to repeat the cast and got a better reading (average depth = 150 meters) began line pattern

** After a few lines of learning the computer program, SS Foye allowed me to drive the boat for almost the rest of the time—my experience on boats made this part so much fun—especially using the computer imaging as a navigational chart**

17:30 arrived back at RAINIER for dinner

I was truly impressed with the amount of different technology aboard these ships: 5 computer screens, 2 key boards, and a lot of different software programs used to immediately process the information we were gathering. This was also a great change from being on the big ship all day!

Personal Log

This was definitely my favorite day on the ship so far! The fog lifted early this morning to reveal beautiful islands, puffin, sea gulls, kelp, and even a whale! I was able to experience what it is like to have to make computer programs do what you want them to do (any researcher knows this isn’t always easy), and I had to do this on a rocking boat (for all of you “land researchers”, I suggest you trying it once!). SS Foye, ENS Welton, and ENS Samuelson were all extremely helpful and very good at explaining the technology and theory behind what we were doing. I was extremely impressed with how everyone handled various problematic situations. Computers and technology can be very frustrating sometimes, and the crew aboard the boat handled everything optimistically and professionally. SS Foye asked if I ever would consider giving up teaching and join NOAA—after my experience today, I said I would definitely consider it!

Question of the Day:

What is the effect of different densities of water on sound waves?