Reserve battery collapse and an unlogged false alert at Kandla
During a WPC and port state control inspection at Kandla, the inspector asks for a demonstration of the reserve source of energy on a 3,200 GT general cargo ship fitted with an emergency generator. On the GMDSS battery bank - 24 V lead-acid, 200 Ah, installed four years ago - the panel shows 27.2 V on float charge. When the AC supply is switched off and the full GMDSS load applied, the voltage falls to 22.0 V within 18 minutes and the MF/HF transmitter will not key at full power. The charger's boost lamp is out and its ammeter reads zero, even before the AC is removed. Cell specific gravity readings range from 1.250 to 1.150, with one cell at 1.105. Separately, the radio log has no entry for a DSC false alert transmitted on 2187.5 kHz three days earlier; the second officer says he 'reset the alarm and told the master'. The inspector says he will consider a detention.
1. State what the reserve source of energy must provide and decide, with reasons, whether this bank passes.
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The requirement
A reserve source of energy must be independent of the main and emergency switchboards and must supply the GMDSS installations - VHF, MF/HF or Inmarsat, the DSC watch receivers, the alarms, the MSI receiver and the lighting needed at the radio position - for at least one hour where the ship has an emergency source of electrical power complying with SOLAS II-1, or six hours where she does not. This ship has an emergency generator, so one hour applies: but one hour of the full load, not of a float-charged bank sitting idle.
Does it pass? No.
- 18 minutes to 22.0 V under load is roughly a third of the required endurance, before any allowance for ageing.
- 22.0 V on a 24 V lead-acid bank is about 1.83 V per cell - deep into the wrong part of the discharge curve - and explains why the MF/HF transmitter will not key.
- Specific gravities of 1.250 (healthy), 1.150 and 1.105 show a string that is part sulphated and part failed. One deteriorated cell in a series string drags the whole bank down, and the healthy cells cannot compensate.
- A charger ammeter at zero with no boost means the bank has been sitting, not cycling - consistent with the sulphation.
Verdict: failed reserve source. The ship is not in a condition to sail, and the inspector's detention warning is well founded.
2. Set out your fault-finding plan, what you can realistically fix at the berth, and what you should tell the master.
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Fault-finding, in order
- Charger and AC side: check the AC input breaker and fuses, the charger output voltage and current, and whether the unit is in standby or off. Zero amps into a 22 V bank means either no AC supply or a dead charger; both leave the bank flat.
- Cells: measure each cell on load with a load tester and take hydrometer readings. The 1.105 cell with a low on-load voltage is the culprit. Check electrolyte level (top up with distilled water only after charging), terminals and inter-cell links for corrosion and torque.
- Circuit: battery isolation fuses, the changeover switch to the reserve source, and the DC distribution to the radio console. A high-resistance joint shows as a voltage drop only under load.
- Load test: with the charger off, run the full GMDSS load for the required hour, logging voltage every five minutes.
What you can do at the berth: replace the failed cell or string, repair or replace the charger, clean and torque the terminals, and run a short load test. What you cannot do: complete a credible one-hour full-load endurance test on a patched bank. A four-year-old bank with one failed cell should be replaced as a set - mixed-age cells fail again within months.
Tell the master plainly: get the class surveyor to witness the replacement and the test and record the result before the inspector returns; if spares are not available, delay sailing. Sailing on an untested reserve source is the one finding that turns a defect into an unsafe ship.
3. Deal with the false alert: what should have been done on the day, and what should be done now, three days later?
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What should have happened on the day
- Cancel on the same service. A DSC distress alert cancellation on 2187.5 kHz to all stations with the correct MMSI, position and time, followed immediately by radiotelephony on 2182 kHz: 'All stations, this is [name, call sign, MMSI], at [UTC time] I transmitted a false distress alert on 2187.5 kHz; please disregard; out.'
- Tell the RCC. Inform the nearest coast station or MRCC (Indian Coast Guard) by any means - DSC, radiotelephony, Inmarsat or telephone - so the SAR file is closed before an asset launches.
- Tell the master and record it.
What to do now, three days late
- Still notify the coast station or MRCC in writing: date and time UTC, position, frequency, MMSI, nature of distress shown, cause, cancellation attempted, and corrective action taken.
- Make the radio log entry now, marked as a late entry with the reason. Do not backdate it. Include the inspector's finding and the correction.
- Fix the cause: protect the distress button against accidental operation, brief the watchkeepers, and post the reset and cancellation procedure at the console.
Why it matters: a false alert on 2187.5 kHz ties up the MF DSC watch and can launch a search. The log is the legal record showing whether the ship dealt with it. 'I reset the alarm' is the classic reason a false alert becomes a disciplinary matter instead of a closed incident.