A few years back, I found myself at a winery on Seneca Lake in upstate NY. While enjoying some of the local Rieslings, I noticed some photos hanging on the wall of what appeared to be a cardboard boat race. There were boats of all shapes and sizes. Some looked basic in shape and design, while others were eye popping in their size and creativity. The boats ranged from pirate ships with over 20 people on board, to a near exact replica of the General Lee. After a few questions, I found out these pictures were from the annual Watkins Glen Cardboard Regatta. I knew then and there - we were going to make a boat for this race - and we were going to win!
The next year, we blocked off a month's worth of evenings and and started to turn this dream into a reality. Having never made a cardboard boat, I turned to Google for instructions. I was shocked to find nothing with the level of detail that I was looking for. We were left to chart our own course, and pioneer some new construction methods along the way. I hope this Instructable serves to help fill this void, and hopefully inspires others to join in the fun of glory of cardboard boat building!
Did we win? You'll just have to keep reading to find out ;-)
Step 1: Gather Your Materials
* Cardboard - lots of it: There is lots of free cardboard out there, but you have to get creative to get your hands on it. Start with your local furniture stores. They have the large refrigerator boxes and other large packing boxes that you'll want. I have found that Lowe's and Home Depot shred their boxes every day - but you may be able to talk them into setting some aside for you.
* Tape: There are many kids of tape out there. We used your standard vinyl duct tape. This works good - but not great. We also tried the expensive Gorilla Tape - which had great strength, but just didn't adhere to cardboard as well as the cheaper tapes. The best tape, however, is Tyvek tape - which is used to seal Tyvek sheets on new home construction. This is more expensive, but works amazingly well - especially when the cardboard takes on moisture from the air humidity. Unfortunately, we didn't learn this trick until subsequent boat builds.
* Zip Ties
* Liquid Nails
* Drywall Screws (used as a construction aid)
* Utility knife (with lots of spare blades)
* Caulk Gun
* Drill (for the drywall screws)
Step 2: Boat Design
A great cardboard boat starts with some up-front planning. There are many design considerations that need to be worked out before you start cutting cardboard.
* Boat theme: Get creative! My favorite part of the race is checking out everyone's boats. We wanted a distinctive boat style, and considered a pirate ship or viking boat - but these are very common (and awesome, nonetheless). We wanted something more unique - and the Chinese Dragon Boat fit the bill. These boats are also traditionally very colorful with elaborate painted designs - offering us the opportunity to get creative with the paint job.
* How many paddlers?: We had three adults, and we wanted to be positioned in-line so that we could each paddle on both sides of the boat like a canoe. Again, the Dragon Boat is long and narrow, which suited us well.
* Boat dimensions: We did some experimenting by kneeling on the ground in order to determine how much space each person needed to paddle. We settled on spacing of about 3.5 ft for each person. This drove the main body of our boat to be about 10.5 ft (3 x 3.5 ft). We also settled on a width of about 22 inches, which was narrow enough for us to comfortably paddle from both sides. I did some calculations to determine how deep this boat would sit in the water with the three of us in it, which yielded a depth of about 6". We wanted the sides of the boat to be about 12" above the water line. This gave us our sidewall height of 18" (6+12). (The calculations to determine water displacement are easily accessible on the web, but if you make a boat that gives you enough room to paddle, then chances are that you will not sit lower than 6" in the water)
Check out the attached .pdf file for a more complete set of dimensions.
Step 3: Build the Body
We started by forming up the U-shaped hull section. This gives you the base structure from which the rest of the boat will be built from. Since the rest of the boat is not yet in place, the sides of the "U" will need to be held up with cinder blocks or some other supports.
Next, we constructed the front of the boat out of four parts: the top, center rib, bottom, and sides. The top is a flat piece that tapers toward the front. Note that we didn't extend to a point. This was because we wanted to extend the underside surface of the dragon neck all the way up to the dragon's head. If we would have tapered it to a point like a conventional boat, this wouldn't have been possible (see the pictures to better understand this point).
The center rib is then installed. It acts to give the nose some structural rigidity and holds the top surface in place. Next, add the bottom surface. This surface will overlap with the underside of the boat and extend up to the nose. Trim it to match the profile of the top surface. Close out the sides by contouring two pieces of cardboard to fit between the top and bottom pieces.
We held the pieces in place temporarily using zip ties. Tape works great for attaching two overlapping flat sheets, but performs very poorly when used to attach two perpendicular sheets of cardboard. Zip ties work great for these perpendicular joints. Once we are happy with the position and shape of the nose pieces, secure them in place with cardboard 'angle brackets'. These are simply bent pieces of cardboard that are glued in place with liquid nails. Once the glue dries, the zip ties are cut and removed.
You'll also notice that we used drywall screws to hold various cardboard pieces in place. Liquid nails takes over an hour to fully cure. Screws hold the cardboard in place until the glue is cured. They are then removed.
Follow the same procedure with the tail portion. When complete, you will have the nice looking boat structure - but it's not yet a Dragon Boat...
Step 4: Add the Head and Tail
This is the phase where the boat really started to look like something special. We started with the neck. We sketched and cut the profile of the neck and head and temporarily secured them in place using zip ties and screws. They were permanently attached with more cardboard 'angle brackets'. Ribs were added internally to add rigidity to this part of the boat. We then added the external 'skin' by securing it to the ribs. You'll note that the lower jaw was added separately. This was to done to minimize the complexity of the neck & head. A similar process was done to create the tail section.
With the head and tail fully 'skinned', we added the 'spikes' to the back of the neck and the tip of the tail. These were sketched on cardboard to match the profile of the part of the body to which it would be attaching. We added tabs to each piece that could be folded over and used for attachment.
Step 5: Seal and Prime
We wanted to ensure that that there was no exposed cardboard edges. Every corner and edge was covered with duct tape. The holes left after the screws and zip ties were removed were each filled with caulk. With all openings and edges sealed, we sealed the entire boat with a basic latex primer. We did this for it's sealing properties and to provide a uniform base for our upcoming paint job.
Step 6: Apply the Distinctive Dragon Boat Paint Job
Dragon boats are characterized by ornate and colorful paint schemes. These schemes have two common design features: (1) multiple bright colors and (2) a dragon 'scale' design that covers the body of the boat. We explored many different options, but ultimately settled on a bright yellow base color with a gold neck. The scales were purple and black.
After applying the yellow and gold base colors, we then used a stencil to paint the scales. The stencil was made from two manila folders taped together. I printed a generic scale design off of the web and used spray adhesive to attach it to the folders. The scales were then cut out with an Exacto knife. The scales were painted a section at a time as we worked our way down the boat.
The head was embellished with ornate and colorful flames and teeth. The spikes on the neck and tail were similarly embellished. Finally, we hand painted our boat's name across both sides of the tail: "Puff the Magic Dragon Boat"!
Step 7: Race Day!
After weeks of hard work, it was time to show off the fruits of our labors. Transporting the boat to the race was no small task given that it exceeded 18' in length. We ended up modifying a boat trailer with some cross members of 2x4's for the boat to set on and ratchet-strapped it in place.
Once at the race, we enjoyed putting our boat on display, as well as checking out all of the amazing competition. When it was race time, Puff didn't disappoint. The boat sat about 6" deep into the water. She was easy to maneuver in the water and was surprisingly fast. We took first place in the race for our class, and also took home the prize for judge's favorite.
The boat held up perfectly. There was no water penetration after over 10 minutes in the water. I'm confident she would have held up for many hours in the water. This made it that much more painful to throw her in the dumpster after the race. We surely didn't want to store a boat this big for re-use next year - which didn't give us an alternative. We did, however, remove the head - which is now mounted to the wall of my garage. It serves as a trophy of sorts, reminding us how fun and rewarding these projects can be.