Originally Posted by nigel1
Could it be a bung for the battery vent?
You could remove the bungs now, then replace them when transporting to your boat
Quite common, normally red bungs on the side of the battery which need removing before first use.
You might put a volt meter across the terminals to see if they are well charged or depleted having been sat on a shelf for a long time. Google
the battery code if possible or if a Date of Manufacture is displayed is it reasonably recent?
Had to send a pair back last Spring which were 18 months old and hadn't been charged. The dust layer was a give away.