[Pipeline]

I was on a friends boat going through the channel between Mark Island and Bear Island. When I saw three people that looked like they were working on the three new docks on Mark Island. when we got closer I noticed two kids holding the ends of the slingshot and one pulling the business end. It looked to be about 7-8 feet from the fixed points. Before I could say look out the balloon went from the dock between my friend who was driving and my 11 year old daughter.
The balloon would have hurt someone or at least knocked my friend away from the controls of the boat. Everyone on the boat could've been severly injured.

Marine Patrol was notified.

Has anyone had a similar experience?