“A clean slate”
Deck slates, would be used as deck logs to keep note of important navigational information like knots, fathoms (depth of the water) and wind speed. At the end of the night shift when the calculations were no longer useful, the slate would be wiped clean by the new officer on watch.
Today, to ‘wipe the slate clean means to make a completely fresh start or let go of the past.
Written by Lindsey