This week Denis and I needed to test the CTD because we are going to be using it on the 13th for our first real science trip since I’ve gotten started. We were having trouble with the CTD communicating with the computer. We need to test all the parts of the system between the CTD and the computer. We also decided to make a new termination for the sea cable. The CTD is lowered into the water using the sea cable, the sea cable has three power wires in the core and is wrapped with steel cable on the outside which gives the cable strength and also acts as the ground. We used a megameter to test all the wires. The megameter tests to see if there are any unwanted connections between weirs in the system. We tested the whole system and got a bad reading. So we had to break the system down into parts to narrow down the problem. We found a bad cable from the slip ring on the winch that goes into the winch cab. So we replaced that cable, but we still were getting a bad reading. We found some breaks in the weirs insulation on the weirs that run up from the CTD to the cable so we replaced them too. Once Denis and I finished the new termination we hooked everything back up and tested it out and it worked.
We left on our trip at about 7am. We just needed to go out to the gulf stream and do two CTD casts. One at 5 meters and another at 700 meters. We had a few issues with the CTD not communicating with the computer again. We narrowed the problem back down to the weirs that ran from the CTD to the sea cable. So we ended up removing them all together and attaching the sea cable directly to the CTD. We did our 5 meter cast and it seemed to work well. So then we lowered the CTD to 700 meters and we ran into more problems. We were not getting confirmation that the bottles were firing off or not. So we endup rebooting everything and we got it to work this time but we would have to look into it more when we got back.
On friday we ended up replacing the whole CTD with our back up so we would not have any problems for our next trip which was scheduled for monday. We got the new one installed and tested it and everything worked well.