SEA Currents: Robert C. Seamans
June 22, 2015
Working in the laboratory during a day shift
19°26.4’ N x 156°58.5’ W
Description of location
~ 60 nm S of Big Island
0 knots, hove to for science station
Weather / Wind / Sail Plan
No precipitation with SSW winds at 2-3 force beaufort. 3’ wave swells from SW. Cloud coverage over ½ the sky with both stratus and cumulus clouds. Sailed on the starboard tack under the four lowers with a single reefed main and the forward top sail.
Marine Mammals Observed last 24hrs
~50 shearwater birds
I started the day off with watch from 0700 to 1300 with C-Watch. I noticed that my nausea and sea-sickness has moderated after being pretty miserable the day before. The other main observation I made was that my present sense of comfort was in large part due to the fact that the ship was not going anywhere. The sails were set so the ship was hove to, or effectively stopped for science. For this reason heaving to is my favorite sailing position thus far! Plus, it allows for the deployment of the scientific equipment onboard; extra, bonus for me since I was scheduled to be in the lab with two of my shipmates. Our first deployment was the secchi disk. However, right before setting it into the water we took bets as to how deep it would go before being lost from view. I greatly underestimated the water quality! The secchi disk was seen down to 34 meters and I had guessed only 15m.
Next, we placed a small plankton net into the water and let it collect all kinds of phytoplankton and zooplankton for ~30 minutes. We also maneuvered the hydrocast carousel using an eye-beam from the wet lab to the science deck. The carousel was lowered all the way down to 600m at 35m/minute. Each Niskin bottle closes at its pre-programmed depth as the carousel returns to the surface. Once it was back onboard, secure in its docking station we collected water samples from each Niskin including pH, nutrients, and chlorophyll-a. The pH bottles had to be collected first because they are the most sensitive to changes from the CO2 in the air. Afterwards, we prepared the Neuston net for deployment. This net collects zooplankton at the sea surface for 30 minutes. The cod end jar was placed in a bucket after retrieval and poured out for examination and then replaced onto the net.
Afterwards, the net was rinsed using a saltwater hose from the opening to the cod end to collect any organism trapped along the net. The sample collected from the cod end was then placed into a separate bucket for viewing. Later we separated out all the plastics we could find and counted them as they were placed into their own vial. We also got to pull out all the Halobates (tiny black water striders) from both buckets and placed them into a separate vial. We counted a total of 38! With no time left for further laboratory work we were sent on deck to set the jib sail so the ship could resume her course to the south east in hopes of sailing south of Big Island. To help the ship move faster we then put up the top sail, which is a square sail. C-watch was the first team to be able to put up the top sail!
After lunch we had class that started at 1400 and ended at 1600. We started out with some announcements and then short presentations were given. Anne and I gave a short navigation report. Anne explained how we put up the jib sail and the top sail after all the science equipment was put away. I then went over the distance the ship had traveled according to the Rhumb line from noon yesterday till noon today. I also reported the log distance traveled. The Rhumb line was only 36.5nm while the log distance was 64.7nm.
With the ship heaving to for “science” the ship moved in a non-linear pattern making the log distance much greater than the Rhumb line. Then as a class we were all sent to learn how to take down the top sail and then put it back up. It was much more difficult to set the sail, it involved much more exertive hauling and heaving. But, with everyone’s help this task was accomplished quite quickly.