MCM-11 [46WMCM03; 46WMCM03_I; 46WMCM03_I_SP]

Common issues

• Antenna/probe fouling from cargo residue or condensation affecting signal return
• Signal processing drift causing level reading error
• Cable gland/connector corrosion at the tank penetration
• Stilling well blockage or damage causing erratic readings (where fitted)
• Power supply/intrinsically safe barrier faults
• Calibration loss after a power interruption
• Seal/gasket degradation at the tank-top mounting, risking loss of gas-tight integrity

Inspection checklist

• Function/calibration check against an independent level reference (e.g. manual sounding/UTI tape)
• Visual inspection of antenna/probe for fouling or damage where accessible
• Check tank-top mounting seal and cable gland for gas-tightness and corrosion
• Verify intrinsically safe certification/barrier and cabling are intact and undamaged
• Check the display/local indicator agrees with the remote cargo control room reading
• Confirm high-level and high-high-level alarm setpoints are correctly configured and tested
• Verify the stilling well (if fitted) is unobstructed

Service intervals

Critical spares

• Cable gland/connector kit (IS-rated)
• Local display unit
• Mounting seal/gasket

Safety

• Overfill risk if the gauge and an independent high-level alarm are not cross-checked - never rely on a single level device for cargo overfill protection
• Work on tank-top mounted equipment on cargo/chemical tanks requires gas-free certification and hot-work precautions as applicable
• Intrinsically safe barriers must not be bypassed or substituted with non-IS-rated components

Class survey

Cargo tank level gauging and independent high-level alarm systems are surveyed under the tanker's cargo control and overfill protection arrangements; class checks that the gauge, the independent high-level/overfill alarm, and their calibration records are current, per the vessel's applicable SOLAS/IBC Code requirements, at Annual and Renewal Survey.