Tuesday, March 22, 2016

Crews Buoy Overhaul

With our Crews Buoy down for multiple months I was eager to get back to Little Cayman to address the issues plaguing our installation as well as to do some serious maintenance to the buoy's running gear. The good news was that the buoy was already on shore so I could get to work straight away.
         Upon arrival Feb 15th I took stock of our situation and proceeded to start diagnosing issues. Initially the buoy was blowing a fuse to the CR1000 data logger in the Battery Junction box, which in turn basically shut down all the comms (cellular and RF) so the buoy was completely silent. The main problem was that upon replacing the fuse it would wait approx 48 hours to blow! After checking continuity and finding this to be good through the whole wiring system from the instrument back through to the fuse holder and all the way to the CR1000 data logger, I decided to remove the innards of the battery junction box to the lab for closer inspection. After tearing down to the heart of the CR1000 we found corrosion on a small electrical component on the circuit board.


During this process I was helped by Paul Maneval whose programming knowledge was invaluable to the installation of the new CR1000. Also I would like to thank Jon Fajans for quickly sourcing a CR1000 for us and updating the OS on it for us. Due to the fact that there are two CR1000 data loggers in the buoy that need to be simpatico in order function correctly we then had to update the one in the Met junction Box to the same OS as the new one. We also had to transfer the old CR1000 files to the new one in order for all the systems to function as they did in the past. This did require some trial and error but eventually all systems were operable. Of note, it is important to have a field laptop that still has RS232 connections and ethernet connections otherwise field maintenance would be impossible. Luckily we still have a tough book floating around. I suspect these will be like dragons teeth shortly.
                    After sorting out the main issue we also found our WXT520 to be dead. This has also been replaced with a back up unit. I also replaced the instrument cables to the surface Bic, U/W Bic and CTD as these were suffering from salt spray erosion and U/V radiation to the point that inner wires were showing at multiple bends in the cables.
                  The running gear connecting the buoy to the ocean floor has also been replaced with new lines and float buoys. New zincs have been added to the buoy's U/W frame. New desiccant has been added to the instrument canisters. In all this has been our most thorough maintenance operation and should be good for the next two years.
                  The buoy was splashed and re-deployed March 13th 2016 and should have been sending good data around 3pm eastern time.