Sinking lifebuoys have already appeared on MAC, now the US Coast Guard has issued an alert regarding replacement batteries on emergency equipment. In this case it was the floating water light attached to lifebuoy that sank thanks to a replacement battery that was the wrong weight.
While conducting an annual inspection a Coast Guard inspector picked up a ring buoy’s water light and noticed that it felt heavier than usual. The master of the vessel was notified and he then agreed to perform a float test. When the ring buoy and its water light were tossed into the water, the water light instantly sank about 5’ to the end of its painter. Apparently, the last time the battery was replaced, a heavier battery than the manufacturer’s recommended battery was used. This occurred despite the water light’s labelled instructions regarding the correct battery type.