There has been some discussion about what “2-part marine urethane foam” to use when filling the PVC pipe. While SMCC suggests “Poly-U-Foam” (available on line for about $40/quart), there are probably other types in smaller qquantities that will do the job. US Composites sells a “4-lb kit” for about $20 (catalog # “FOAM-0204”). In fact, as Jason Hyatt (Mass Maritime) suggest, we MAY be able to get by with a can of “Great Stuff” from your local hardware but we do not know yet how well this will hold up in seawater. Note that we did not use any foam at all for the first few years we deployed drifters. We only added this extra buoyancy within the pipe in hopes that the transmitter stays afloat despite the inevitable loss of the other flotation.
MATE Drifter Blog
Thanks to our colleagues at MATE, you can follow a blog of drifter experiences at: http://coseenow.net/mate/ . To make an entry in the blog, click on the “Register” link , “Log in”, and blog away. Note that they already have a set of “categories” to choose from including, for example, “curriculum development”, “collaborating with scientists”, etc. Under the “resources” page, there is a link back to the various SMCC/GoMLF/NOAA effort. I plan to enter this newsletter in their “Tracking the Drifter” blog.
We have compiled a gallery of drifter photos (linked from the bottom of the “drifter construction and technology” document at http://www.nefsc.noaa.gov/drifter/ ) and may harvest some more from the blog. Please send your contributions to email@example.com (or upload them to the blog) and supply the photographer’s name so that we can give the proper credit.
Tracks of the Month
There are always particular tracks that stands out from the rest. This month, the Cape Fear Community College drifters have provided some interesting tracks. Their first drifter that was deployed just a few weeks ago has traveled over 2000 kilometers in the Gulf Stream but, even more amazing, their 2nd drifter traveled over hundred kilometers in one direction, turned around and came directly back nearly to where it started. CFCC is now working on building more drifters and some of the students are designing a wooden (ie biodegradable) drifter!
New Drifter Designs
Two new-style drifters will be deployed within the next few weeks. One is the “Kathleen” bucket drifter which will track the very-near surface waters of the Merrimack River Plume for Dr. Dan McDonald of UMASS Dartmouth. Many of these units have powerful strobes, Garmin receivers, temperature and salinity sensors installed along with the TrackPacks. There will be a total of 27 units deployed at the river mouth during an outgoing tide after a large runoff event. Stay tuned.
The other new style drifter, developed recently by Ruben Davis of DatisSystems of N. Falmouth, MA, eliminates the need for satellite transmissions by implementing a radio-based system for near-shore high resolution applications. Stay tuned for the result of these prototypes.
TrackStick GPS receiver
Jason Goldstein and Win Watson (UNH) have come across the TrackStick. Google this and you will see a compact device that may be a nice alternative to the Garmin units (for internal storage of fixes) and apparently provides more battery life.