Innocence

Taking this photograph made me wonder whether there are there rules for naming boats.  Can you call a boat any name you want?  I wonder what prompted the owner of this boat to call it Innocence, or why would you call a horse Brian?  Why not could be as good an answer as any, but names have a significance and importance which is not always immediately obvious to the rest of us.  So Innocence will remain a mystery for the time being.