November 2014 Annual service and repair

During the 9-14 Dec period Jon Fajan was invited over to conduct an annual maintenance and repair of two Tobago CREWS. During this period the exterior of the buoy (floating base and metal supports were cleaned of barnacles and other fouling.  All instruments were inspected, cleaned and replaced.  Two months prior (September) the Buccoo CREWS was not transmitting data.  The cause was thought to be a power surge, which triggered a power failure.  A relay was by passed and the power restored resulting in the transmission of data from the CREWS.  The CREWS was redeployed on 13 Nov 2014 but due to overcast and rainy conditions we were unable to reset the ASC because the solar panels are only putting out about 13V today.  Removing and replacing the positive wires from the battery did not reset.  The power was put back on the bypass and an attempt will be made to reset during the service visit to repaint the hull in the very near future.  If at that point the voltage from the panels exceeds 13.5V and the relay  still does not reset – the ASC (it would have failed within the 1 year of deployment) may have to be checked by YSI. The buoy was deploy without the RMY temp/rh sensor and without the turbidity and chl-a EXO2 sensors as these are all in need of service. Cellular and RF communications were confirmed from multiple sources.

Previous basic maintenance was also conducted in August 2014, July 2014, June 2014, April 2014, February 2014.  Inspections were inconsistent due to team changes, sea conditions and other logistical constraints.  Ideally Buccoo should be monitored twice monthly due to the high rate of fouling, however this is not logistically possible.

April 2014 scheduled maintenance

The Buccoo Reef CREWS given a basic maintenance service on 24st April 2014. Moderate barnacle and algal fouling was noted, but less severe than the last time. No obvious physical damage was noted, but barnacles were noted to have attached to the top of the EXO2 at the connections of the cables. Some fouling "crud" was also noted on the female connector then de-coupled from the EXO2.  The copper coating remains intact and holding. The failure of the Turbidity probe to pass the QC test remains unresolved (the same issue exist for ARTO1), even though it all seems right during the cal.  Recommended action is a firmware upgrade.

Possible error with barometric readings. Pressure ranges from 1013-1015 millibar throughout the day. A 1millibar change suggest a 10m displacement.

March 2014 Scheduled Maintenance

The Buccoo Reef CREWS (BUTO1) was serviced on 19/03/2014 after several months of basic maintenance. Rough seas prevents schedules maintenance in December/January.

Pre-cal CTD

Depth: 1.05m     
Temperature: 27.23
Conductivity: 56155
Salinity: 35.5

Mooring lines, the buoy and the hardware attached to the buoy remained intact and with no noticeable damage.  Mooring lines and the buoy  were heavily fouled with green filamentous algae and sessile barnacles.  The anchors remained intact with no cracks or weaknesses noticed.  The eastern subsurface buoy has shifted up to below the surface of the water, and will be adjust on next visit.

The EXO2 was heavily fouled primarily with sessile barnacles at both ends.  The fouling was to the extent that it prevent the opening of the unit from the protective casing and the release of the probes from the EXO2 base unit. Most of the copper coating surrounding the probes had been oxidised but no physical damage was noticed on the sensors.  The probes were thoroughly cleaned of all barnacles, algae and other encrustations. All debris removed from the threading and krytox gel reapplied to all ports prior to reconnection to the base unit.  On recalibration it was noted that the conductivity/temperature probe was faulty (during calibration it registered temperature of 1.xx e-9 and conductivity readings of 96500 in the conductivity standard) and has been replaced with a new probe.  The faulty probe has been sent to YSI from examination. The new probe passed calibration process.  A QC result was generated during the TSS calibration process for reasons undetermined.  This also occurred during the first installation of the CREWS.

Buccoo is a high fouling area and as a result more regular checks to BUTO1 will be made. Basic checks will be made twice per month to clean any fouling and recalibration exercises conducted monthly as best as possible.

barnacles settling at junction between protective cap and EXO base inhibiting smoothing opening of unit

Fouling within protecting casing

BUCO1 anchor

Copper coating deterioration

Range of sizes of barnacles colonising EXO2

Deterioration of copper coating on probes

Tough algal mat and barnacles covering protective cover and probes

Settlers on top of EXO2

Fouling on CREW buoy