Tag: multibeam echo sounding

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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?

Posted on

Leyf Peirce, July 8, 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 8, 2004

Time: 09:00
Latitude: N 55°41.71
Longitude: W 158°03.81
Visibility: < 1 foot
Wind direction: 230
Wind speed: 10 knots
Sea wave height: 0 – 1 feet
Swell wave height: 0 – 2 feet
Sea water temperature: 10.0 °C
Sea level pressure: 1021.3 mb
Air temperature: 10.0 °C
Cloud cover: fog

Science and Technology Log

As I am typing my journal entry, I learn there are several good pictures on the network server of the RAINIER and its crew. Here is just one that I found:

Peirce 7-8-04 Rainier
NOAA Ship RAINIER underway. Credit: NOAA.

From this picture, I can see that the aft most launch ship has been launched for survey, for there are 3 launch boats on either side of the ship. I talked further with the crew today about interesting characteristics of this ship, including a “field trip” with Lt. Kevin Slover to inspect the hulls of the launch boats to see the echo sounding devices. I learned that there are actually 3 different types of these devices: one with low resolution for very deep water, one for a little higher resolution of deep water, and one with high resolution for shallower water. These devices cost up to $25,000! I was able to get pictures of the three types; however I am not able to download them onto the computer yet. Lt. Slover also showed me more of the Caris program, the most recent computer program used to collect and analyze the data. I say most recent used, because these programs are constantly being changed and updated to be more accurate, user-friendlier, and display better graphics. One of the most interesting features of this program is not only its accuracy, but also the ability to look at the computer created images of the ocean floor from any angle. One of the images pulled up as an example showed a shipwreck off of the coast of Seward in about 38 meters of water. The details of this sunken ship were almost crystal clear! Of course, this is after the data has been corrected and cleaned. I hope to work more with this program as we start the launches tomorrow and Saturday.

I also spent some time on the bridge again today. There, I learned a few interesting trivia facts about this ship:

  • The RAINIER was built in 1968 along with 2 other identical ships, the MT. MITCHELL and the FAIRWEATHER, all specifically for NOAA; these three were commissioned in 1969
  • There are 2 main engines aboard this ship, both have 1200 Horsepower and they are the same type of diesel engines as those used in locomotives
  • To figure out the cloud height, one can apply the equation: (wet bulb temp – dry bulb temp)*126.3; there was some dispute on how accurate this is, but for today it works since the wet bulb temperature = dry bulb temperature, so the cloud cover, according to this equation, is at 0 feet which is true since we are in a cloud today with all of this fog
  • The boat was originally built to support 4 launch boats and 2 life rafts, however it was recently modified to have 6 launch boats on it; to counteract this weight up top, more ballast had to be added to the bottom

A launch boat also left today at 08:00 to conduct further hydrographic research, and the RAINIER maintains her course, “mowing the lawn” in a section of uncharted waters between Kodiak and the Shumagin Islands. Once this area is completed, we will head to the Shumagin Islands to anchor and send more launch boats throughout the next week before we return to Kodiak. This is such an adventure!

Personal Log

The foghorn blows every 2 minutes on this ship, and it acts as a great wake up call. This morning, the horn reminds me that we are sailing in a sea of uncharted and now seemingly invisible territory. I feel like an explorer thrown into the time of Captain Cook, half expecting to see a pirate ship emerge from the eerie blanket that surrounds us. However, the multitude of technology aboard this ship flaunts the modern times in which we live and, in doing so, destroys any hope of true exploration of the unknown. Still an explorer at heart, I also still find adventure in what we are doing. We are still conducting hydro research aboard the RAINIER, “mowing the lawn” across uncharted territory, so we are only moving at about 7 knots. A launch boat was also sent out today to investigate near by waters. As I sit here responding to emails and learning even more about how this ship works, I am anxious to see the data that is collected now be processed.

Question for the Day:

In talking with P.S. Shyla Allen and Lt. Kevin Slover, we discussed the rewards of this job—how does this work help society? Both agreed that one of the most rewarding, but somewhat scary, aspects of this job is being able to accurately chart and re-chart high traffic waters. They both said that there are often calls from local fisherman demanding more detailed and more accurate charts. P.S. Allen informed me that there is a group of retired U.S. Coast Guard members that will conduct their own charting research in order to expedite the charting process. While helpful, this is not always the most accurate information. However, I did begin thinking about ways to include local fisherman in the research; to ensure the data that they collect is more accurate. My question for the day is more of an engineering design problem and proposed solution defined:

Problem: Local fishermen travel the coastal waters along Alaska to make a living. However, these waters are poorly charted, if charted at all. As of now, fishermen use a “Hummingbird” device to measure the depth of water where they travel, but there is no electronic device that can record this data accurately, correct this data for margins of error, and combine this data to produce an accurate nautical chart aboard these fishing vessels. While boats such as the RAINIER have this capability, expanding the number of vessels capable of collecting and analyzing such data would expedite the nautical chart updating process.

Proposed Solution: Design, test, and implement a device that abides by the following parameters: not very expensive, accurate, maintains the same abilities as the multibeam echo sounding devices aboard the RAINIER, has the capability of communicating with the computers aboard the RAINIER to share information collected, and can be mounted on the fishing vessels in such a way that it will not alter steering or speed.

I asked Lt. Slover if there is much government funding for such engineering projects, and he assured me there is—most of the U.S.’s imported goods arrive by ship, so more accurate and up to date nautical charts are a large priority.