ENS Meghan McGovern and ENS Olivia Hauser, Jr Officers, looking at unmarked buoy sighted on the bridge
Weather
Weather: Foggy, cloudy
Visibility: 1.5 nm
Wind direction: 130
Wind speed: 6 knots
Swell Waves direction: 260
Swell height: 1-2 ft
Seawater temperature: 11.7 degrees C
Sea level pressure: 1014,9 mb
Temperature dry bulb: 12.8 degrees C
Temperature wet bulb: 12.2 degrees C
Personal Log
I continue to work on activities that can be incorporated into my classes. The RAINIER is underway to Seward, Alaska. There is some excitement on the bridge after lunch, when an unmarked buoy is sighted on the port side of the ship. Several officers come to the bridge to observe and the buoy is marked on the chart. As it turns out, this is not a “find” and was updated on the Notice to Mariners put out by NOAA.
After dinner, fog moves in and the RAINIER sounds the fog horn. As a sailor, I don’t like fog. I am comforted by the fact that I am aboard a large ship with good radar system to detect approaching ships. The fog begins to lift a little and the last day of the cruise, like the first day, is marked by seeing humpback whales.
If this had truly been a “find”, the buoy would have been penciled in and added by NOAA.
Weather
Cloudy Visibility: 6 nm
Wind direction: Light
Wind speed: AIRS
Wave direction: 200
Swell height: 2-3ft.
Seawater temperature: 8.9 degrees C
Sea level pressure: 1018.0 mb
Temperature dry bulb: 12.2 degrees C
Temperature wet bulb: 12.2 degrees C
Personal Log
We are anchored in East Bight and I continue to work on lesson plans. We are scheduled to get underway today for Seward. I am excited because I can spend two days in Seward seeing glaciers and fjords. Although, the weather has changed and it is cloudy and overcast, there is an up side to the weather. Geologic features that are often obscure when the sun is shining show up when the weather is overcast and more contrast is provided. I take the opportunity to showcase another basic geologic feature that is well exposed.
A scenic view of part of the Shumagin Islands and the Haystacks formationThis is a type of drainage pattern is known as radial. The drainage originates from a central point and occurs on elevated features such as volcanoes.
Weather
Clear Visibility: 10 nm
Wind direction: 290
Wind speed: 6 knots
Seawater temperature: 10.6 degrees C
Sea level pressure: 1020.5 mb
Temperature dry bulb: 15.6 degrees C
Temperature wet bulb: 12.8 degrees C
Personal Log
We are anchored in East Bight and I continue to work on lesson plans. It is a beautiful clear day with many great photo opportunities. I take advantage of the expertise of Intern Umeko Foster, who gives me a crash course in using the sextant. I reluctantly admit to owning a sextant for many years and not using it to navigate. Umeko is an excellent teacher and for the first time I am able successfully move the sun to the correct position on the horizon! As a bonus, Umeko demonstrates the correct way to read degrees and minutes. After dinner, Able Seaman Leslie Abramson drives the liberty boat to and from the beach so crew members can enjoy a little r and r. I ask Leslie to take me on a cruise to a nearby outcrop of rocks with many geologic structures.
Geologic structures are everywhere in this outcrop. Save this picture to your desktop and enlarge it. How many faults, dikes, sills, and folds do see?
TAS Jacquelyn Hams uses a lead line to determine depth during a shoreline survey
Weather
Cloudy Visibility: 10 nm
Wind direction: Light
Wind speed: AIRS
Swell Waves direction: 350
Swell height: 0-1
Seawater temperature: 10.0 degrees C
Sea level pressure: 1018.5 mb
Temperature dry bulb: 15.0 degrees C
Temperature wet bulb: 12.2 degrees C
Science and Technology Log
Today I go out on a small boat with Jim Jacobson, Chief Survey Technician, ENS Megan McGovern, RAINIER Junior Officer, Erin Campbell, Survey Technician, and Corey Muzzy, Seaman Surveyor and Coxswain to conduct a shoreline survey in Porpoise Harbor. The objective of the shoreline survey is to verify some points which were identified by LIDAR (Airborne laser mapping) which may or may not be rocks along the shoreline. LIDAR is an emerging remote sensing technology that integrates the following three subsystems in to a single instrument mounted in a small airplane to rapidly produce accurate maps of the terrain beneath the flight path of the aircraft.
LIDAR (LIght Detection And Ranging) is similar to radar or sonar in that it transmits laser pulses to a target and records the time it takes for the pulse to return to the sensor receiver
Fixed reference systems
Global positioning satellite system (GPS).
Bathymetric chart reflecting points for investigation during shoreline survey
LIDAR utilizes a pulsed laser rangefinder mounted in the aircraft. While most LIDAR systems are designed to measure land elevations (“topographic LIDAR”), the technology can also measure water depths if designed with a light wavelength which will pass through water (“bathymetric LIDAR”). Bathymetric LIDAR accurately measures the travel time for both the laser return from the sea surface and the return from the seabed. If the speed of light is known and one corrects for angle, scattering, absorption at the water surface and other biases, the distance to the sea surface and seabed can be computed from these times. The difference between these distances is the water depth. In general, bathymetric LIDAR is less accurate and lower resolution than the multibeam sonar systems on RAINIER’s launches, but it can be much faster and safer in some areas.
This is a picture of a sonar image taken on the boat. The spike on the image represents a rock.
We have several LIDAR points to verify. RAINIER has been asked to investigate these points because they are around kelp which LIDAR cannot penetrate. The boat is equipped with vertical beam echo sounders so that the bottom depth is known. Once the boat reaches the point of investigation, the coxswain drives a star pattern around the point to make sure that all sides of the potential obstacle have been covered. Lead lines are used to confirm depths close to the shoreline.
The presence of a rock is indicated by the peak in the sonar image on the left. Depth of the recorder is 32.4 feet. We are able to survey all but three of our points until we have engine problems after crossing on the edge of a thick patch of kelp. Unfortunately, the engine will not start and we have to call for a tow. On the way back to the ship, I have yet another photo opportunity for some geology pictures. Nagai Island lies within a major fault zone of the Aleutian Islands so many of the rocks are folded and uplifted into spectacular structures. The beds pictured in the photograph below were deposited according to the Principle of Original Horizontality; therefore they should be stacked on top of each other in a horizontal position. Look at them now!
ENS Megan McGovern, RAINIER Junior Office and Leslie Abramson, Able Seaman.Imagine the stress that tilted these beds to the current position.
