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Current position of the SSV Corwith Cramer. The equipment on board is experiencing some techincal difficulties, so not all features and information may be available. Use the tools, top right, to change the map style or view data layers.

SEA Currents: SSV Corwith Cramer

January 13, 2017

In the Island’s Lee

Claire, B Watch, Miami University

SEA Semester

On the head rig

Ship's Log

Current Position
17° 44.6’ N x 066°18.4’ W

Ship’s Heading & Speed
355° PSC, & changing course to 145° to head southeast along Puerto Rico’s southern coast,  2.7 knots

Sail Plan
jib, forestays’l, mainstays’l, main

Sunny and some wind

Today we continued sailing along the southern coast of Puerto Rico. We sailed southeast for most of the day, allowing for the deployment of all of the science gear, including the Secchi disk. The Secchi disk looks exactly like a white dinner plate, but instead of holding food, it is super science-y  and awesome. The disk allows us to calculate light penetration into the water, which in turn gives us information about phytoplanktons’ preferred depth. Phytoplankton really like to hang out above what’s known as the “1% light level,” which is where there is only 1% of light penetration remaining. The Secchi disk depth is the 18% light remaining marker. That depth we put into an equation to find the 1% depth, somewhere above which the phytoplankton will likely be most abundant. The Secchi disk is lowered into the water, and stopped only when all spotters on deck can no longer see the white dinner plate-like object sinking into the water. Aboard, we had a competition today to see who could guess the Secchi disk depth most accurately. The student winner was Brittany on A Watch, and she got a homemade peanut butter cup which looked delicious.

In addition to the super rad science that we do every day, all day, aboard the Corwith Cramer, we also do a fair amount of sailing. Today, we sailed southeast, away from the coast of Puerto Rico, until the winds became quite rowdy and Captain Sarah decided it was time to gybe and head back in towards shore. We’re working our way upwind. For much of the afternoon, we steered straight north, heading right back to the coast, where we are somewhat protected from the winds by the island. Tonight, we will continue our course heading east along the southern coast of Puerto Rico.


Categories: Corwith Cramer, • Topics: c270c  science  sailing • (1) Comments
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Leave a note for students and crew to read when they reach their next port and have access to the internet!

#1. Posted by Barbara on January 19, 2017

Thanks for blogging.  I am sharing this with my 3rd grade class today.  We are going to investigate a Secchi disk and phytoplankton.  Keep the science coming!



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