Each day after lunch, while Claire went down for her nap (and all the others had down time), I would take the children and tell them stories from the Bible that had "sea" themes.
Like the "the foolish man built his house upon the sand"
or "I will make you fishers of men"
I had all these stories in a treasure box and I would open this box to bring out the story and a craft or activity to do.
One day we talked about pearls. I showed them some real pearls that my mother has given me and how to tell a real pearl from a fake one. (you bite it. a fake pearl will leave teeth marks) Then I gave them each a treasure map and they had to go on their own treasure hunt.
We will tell the next generation the praiseworthy deeds of the LORD,
his power, and the wonders he has done. Psalm 78:4