NOAA Teacher at Sea
Debbie Stringham
Onboard NOAA Ship Fairweather
July 5 – 15, 2005
Mission: Hydrographic Survey
Geographical Area: North Pacific, Alaska
Date: July 7, 2005
Weather Data
Location: in transit
Latitude: 55 37.5’ N
Longitude: 156 17.8’ W
Visibility: 10 nm.
True Wind Speed: 14 kts.
True Wind Direction: 295
Sea Wave Height: 1 ft.
Swell Wave Height: 2-4 ft.
Swell Wave Direction: 270
Sea Water Temperature: 13.1 C
Sea Level Pressure: 1007.6
Sky Description: Clear
Dry Bulb Temperature: 14.9 C
Wet Bulb Temperature: 13.0 C
Science and Technology Log
I woke up at 0300 to stand watch on the bridge with the XOs– Shifts are usually four hours on and eight hours off. I learned how to use the Combined Wind Plotting Board Calculator to determine true wind speed and direction. I estimated wave and swell heights and direction and collected data on dry and wet bulb temperatures, latitude and longitude, barometric pressure and sky description. Weather readings are collected every hour on the bridge while en route.
In order to find true wind, one must find the bearing and speed of the ship from a GPS unit and correlate that on the plotting board. Then, apparent wind speed and bearing are taken from an anemometer and plotted on the board. When the board is spun and the two points are aligned vertically, one can correlate those points to find the true bearing and the difference between those two points give true wind speed in knots.
While on the bridge, I also learned the reference system that crew members use to indicate another ship, landmark, or object in the ocean. For example, if a light is spotted at 45 degrees from the bow of the ship, then one would say, “There is a light, broad on Starboard Bow.” If the light were on the portside at 270 degrees, then one would report, “There is a light, broad on Port Beam.” The 360 degrees view is actually broken into bearing points. A point equals 11 degrees and there are 32 points in all. During my watch, I was able to spot whales at both of the locations mentioned above.
Question of the Day
What is hydrography and why is it important?
Answer from Previous Day
1 fathom equals six feet.
