As the Britannia P&I Club informs, the bilge alarm should also store this data for at least 18 months and must also be capable of displaying or printing the data as and when required by official investigators.
In fact, in one recent case, it appears that the batteries in the 4 bilge monitors in question were very low with not enough voltage to display the information.
The make of the monitors was BilgMon 488, and in older models it was not possible for the crew to replace the battery. The newer versions of BilgMon 488 have batteries that can be replaced.
This case serves as a good reminder that engineers should routinely review the stored data and make sure the battery has enough power to store as well as display the date. Otherwise ships can face delays when detained by the USCG while waiting for the data to be retrieved
Britannia P&I Club states.