Three fools go to sea in a bowl, part of the old "Wise Men of Gotham" tradition of tales about a village of exaggerated simpletons. The joke lands in the last line, where the rhyme runs out along with the story. Better appreciated once a child can follow a punchline.
From Mother Goose / Nursery Rhymes (traditional). See the whole collection.
Three wise men of Gotham
Went to sea in a bowl;
If the bowl had been stronger
My song had been longer.
Public domain. Text from The Real Mother Goose (Blanche Fisher Wright, 1916), via Project Gutenberg. View the source edition