It’s a test of buoyancy to see who can return their boat the quickest. The buoyancy boat was specially made to return to its original send off point. As soon as you place the boat onto the water the buoyancy lever starts taking in water. Once it reaches full capacity the lever swings down reversing the paddle direction. The challenge: Weight the boat using pennies in the penny trays on the boat to add more displacement to the boat. See how fast you can return the boat after it reaches a distance of 20 feet. The more weight on the boat will cause the buoyancy lever to switch faster therefore reversing the engine sooner but be careful, the more weight means more water displacement making the boat move slower. Find the magic medium and beat your friends in this fun science game. All parts click together. Its easy to print and assemble with the PDF instructions. Watch the YouTube video: https://youtu.be/fxd72qmHTqM More videos to come... I was visiting Portland and admiring the great freighters that passed by hourly wondering about the bilge water being pumped out of the ships and wondering where that water must have come from. The stability of the ship lies in its buoyancy displacement. The more water it takes in the more stability it has. My cousin and I used to sit along the pear and call out the countries of these grand freighters that muscled along the shore. As they got closer to port they began rising out of the water while pumping water out from their tanks. The science behind buoyancy fascinated me and inspired me to build this boat. Please read the PDF instructions for details. All links for parts can be found in the instructions. The Paddle Boat uses 2 water bottles on either side and requires one 3V~6V electric motor. There is a universal engine mount that can accept almost all electric motors under 2" diameter. You will need 2 switches. Don’t forget some basic wire and 2 or 4 AA batteries depending how much power your DC motor needs. The assembly of the electronics is easy, just follow the diagram in the instructions booklet. A video of the instructions will be posted.