We enjoyed a nice picnic and boat “sailing” a few weekends ago.
I saw a simple idea to make a boat out of tree cookies from this site.  I decided to add string so they would not float too far away!

There was no wind to be felt the day we set these afloat.  The children waited oh so patiently for their boats to float away.  They drifted just a tad but the kids did not seem to mind.  They quickly set off throwing rocks in the water.
We will definitely try this again.  This would make a fun outing with friends.