Station Operations Troubleshooting

Shiptime is limited and expensive so keeping station operations, such as CTD-rosette deployment and recovery, running smoothly are critical to maintaining our station schedule. Station operations are organized for efficiency with stationary operations first (CTD, secchi, vertical net tows) then moving operations such as Manta & Bongo net tows. Although efficient use of shiptime is critical to finish all the scheduled stations & work. Safety is the top priority so protocols for prepping gear for station, deck ops, and 'over-the-side' operations change when the weather is rough. CTD-rosette prep, typically done 20mins before station arrival, may wait until station arrival to insure the safety of all participants & equipment. CTD-rosette descent speed may be reduced to 25-30m/min to minimize strain on the conductive wire.

This page outlines some strategies and general practices for maximizing ship/station time safely:

Primary strategy - redundancy: CalCOFI typically carries duplicate hardware for all mission-critical systems. We carry two complete CTD-rosette systems although only one is typically assembled. Most problems usually require the replacement of a defective or failing sensor, cable, or battery. Two complete sets of nets are onboard so unless the ship equipment fails (hydraulics, winches, for example), swapping out faulty gear should cause a minimal delay. At least two of everything: stopwatches, data acquisition workstations, sampling gear, analytical gear, etc will pay for themselves the first time they are needed.

Secondary strategy - continue station work if possible: while addressing a problem, continue with alternate station work. If CTD operations are not working, move on to other station work such as net tows. Net tows take about an hour, so this will allow troubleshooting problems with the CTD-rosette.

Troubleshooting

Bottle mistrips - rosette bottle(s) fail to close or close at the wrong depth: carousel mistrips are addressed in basically two ways: first mistrip, the trigger is cleaned with a Kimwipe or Q-tip of any debris or biological contaminate that may interfere with the trigger swing. If, after servicing, the same bottle mistrips again over the next few casts, the trigger is replaced. The carousel 'crown' is removed, disassembled and the trigger replaced. Having several spare triggers is highly recommended. Note: that bottle closure at the wrong depth may not be detected until nutrients or salts are run. Lanyard mis-rigging may also cause the bottle to mistrip.

CTD conductive wire problems:

Rough Weather Protocols

DMC Firewall is developed by Dean Marshall Consultancy Ltd