Super Simple Sailboat

Our most recent Science and Swim at Belvidere Pool was the most well attended yet! Perhaps the article in the Warren Reporter helped. This week we made sailboats with easy-to-find materials and lots of awesome duct tape then set them afloat in the pool. I swear the toddler pool looked like it had spawned an armada!

To set the mood, let's start with your morning earworm: "Come Sail Away" by Styx.

Now that we're all humming along together, we can get building! First you need to assemble materials: A tray to act as the hull (we used small cardboard ones donated by Nature's Harvest), a bamboo skewer to act as the mast (a small dowel or pencil will also work), lots of colorful duct tape, a small amount of modeling clay, scissors, wax paper for the sail and an old foam egg carton for the rudder.

You start by covering your hull with duct tap, top, bottom and sides. If you want, you can also build up the sides a bit with tape, to prevent water from coming onboard.

Now you need to attach the mast. Make a small ball with the clay and place to towards the bow of the boat. Then stick the skewer into the clay. Mold the clay around the skewer to hold it in place. Cover this well with duct tape. If you have the time and ability, punching a hole in the hull and pushing the mast through a bit, then adding a bit of glue and covering with duct tape will add more stability to your design.

Next we need to attach the sail. I chose wax paper because it's relatively waterproof and inexpensive. That means you can try lots of different sail shapes, if you like. You don't have to stick with the standard rectangle. Try a circle or triangle or a octagon, if you like! Attaching the sail is very simple: just cut two slits in the paper with scissors and slide it onto the mast. If you plan to change shapes often, using a bit of tape to build up spots on the mast to hold the sail in place will suffice. For more longevity, use a bit of scotch tape to hold your sail onto the mast. In either case, be sure to create a "cup" in the sail to catch the wind.

Over the course of our build at Science and Swim, we experimented with lots of ways to make our sails sturdier, as it was pretty windy. One mom had a great idea: putting a strip of duct tape on the top and bottom of the wax paper to add stability. We also experimented with creating tie lines with tape and using materials like old plastic bags and ziplocks for sails. You can even build a sail out completely of duct tape. This is where prototyping is important! Keep modifying that design until you get it to do what you want!

It's also fun to add a rudder, so that you can steer your boat. (This also illustrates an important idea about fluid mechanics, by the way.) To make the rudder, just cut a piece of foam from your egg carton, cover it with duct tape and cut out a small wedge. Then make a slit in the back of your boat and fix the rudder in place. By changing the angle of the rudder, you can change the direction of the boat. It's a lot of fun to experiment with different rudder shapes too!

Then it's time to take the boat to the water and give it some wind! If you have rough waters, you will need to replace your sails, as the wax paper will eventually break down and start to fall apart.

One creative young man, used leftover egg carton pieces to make fun characters for his boat. You can too!

Have fun and enjoy sailing the high seas... or your backyard pool!

The 2-liter bottle boat

Maker Camp officially kicked off on Monday, July 8 and the first project on tap was a boat built from a two-liter bottle with a paddle made of plastic lids. It completely captured Gwen's attention, and we had a lot of fun with the build!

The concept is simple: Use empty soda bottles to create the buoyant body of the boat, then add paddles powered by energy stored in the tension of twisted rubber bands to make the boat move. Throw in the use of colorful duct tape, and you pretty much have a perfect project for a summer day!

We started by attaching two bamboo skewers to the sides of our washed bottle. Later we switched to stronger dowels, because the skewers tended to bend too much under the stress of the rubber bands.

Then you measure between the dowels and create your two paddles. They need to have a length that is 1 inch wider than the distance measured and a width that is 1 inch shorter, creating a rectangle. We cut ours from the top of an old Rubbermaid-style container. Once cut, you create a slit in the middle of each and join them into a cross shape (+). We found it helped to secure the paddles in place with duct tape.

Next you attach two 1-liter bottles to either side of the larger bottle. We positioned ours just below the dowels with the backs just about even with the 2-liter. Placing them any further back interfered with the movement of our paddles. As we continued to trouble shoot the project, we found that when attaching the dowels and small bottles, it was important to pay close attention the shape of the larger bottle. If you apply tape across an inward curve, it will pull everything out of whack and the paddles will jam.

The last step is to attach the rubber bands so that they hold the paddles in place between the two dowels. We found we needed to trim our paddles a bit more, to be sure they had enough clearance to move. Gwen wanted to trim them a lot and we talked about why that may not be the best idea, since the amount of surface area directly affects the force created, thanks to the resistance of the water against that big flat surface. We also found that the length and width of the rubber bands mattered, though not nearly as much as we expected. In the end we opted for "medium" thickness bands that were just barely tight across the dowels before twisting.

To use the boat you twist the paddles, transferring the kinetic energy from your hands to the paddle to the bands and creating tension across the rubber bands. Of course you've now stored potential energy in the bands until you release then and the paddle rotates and propels your boat! Super simple and lots of fun. It was a big hit at the pool, where everyone wanted to know what Gwen had built and see it work.

One of the most fun things was discovering that the direction in which you turn the paddles matters when you release! Turn them one way, the boat moves forward. Turn the other, and back it goes. Spending some time observing both and discussing why it happens was great.

Of course the first hing Big Sister Caitie wanted to do was sink the boat and see if it works as a sub. I guess we'll try that at the pool tomorrow! We also want to experiment with the shape of the bottles to see how they affect the movement of the boat. Would a one gallon milk jug work as well? I guess we'll have to find out!