# Cardboard boats
## Problem

Get Invited to a Cardboard Boat Competition
cardboard boat competition 2010
cardboard boat competition 2008
Civic groups such as a Rotary Club(s) and school engineering departments/clubs can sponsor a fun, family event such as such as a cardboard boat competition. They are a great way to begin building an engineering program at a high school or community college.
The competitions judge speed, themes, demolition survival, most dramatic sinking, best mechanical aid, rube goldberg award, etc.
Get a copy of the rules .. they will typically explain that years "themes" which translates into awards, pictures of the boat in the news and marketing campaigns.
Some competitions have materials that are used to design and build cardboard boats on the spot in the hours before the competition.
Some cardboard boats can cost a thousand dollars and are reused year after year. Some are built over a four week period, are designed to win various prizes, and are thrown away at the end of the race.
The problem is that you have been asked to build a cardboard boat or enter a quick build competition. This can not be avoided for political, fund raising, community building, program growing, student recruitment reasons. Cardboard boats can be simple or a bottomless pit of $20 gallons of wood glue, paint and cardboard debris all mixed together on a floor that will take a year to clean. :

## Conceive

Boat Name
The design should start with a unique name for the boat. This has to be backed up by a narrative or story. This ideally is on a piece of paper that is handed to judges and verbally told to people passing by the boat, in funding raising presentations, and design reviews. The goal is to maximize attention.
Adequate Too
Fruit Cakes
Hop In
SS Sea Lightening I
GEN 11
Tiki
Planned Sinking/Staying Dry
competitive racing
cardboard boat sinking .. video
Most competitions differ from an Olympic rowing race in that the boats should sink. Everyone should get wet. The audience anticipates sinking.
The goal of staying dry destroys competitions. It is possible to build cardboard boats where everyone stays dry. But if everyone stays dry, there is no drama. This is why most competitions have a demolition derby at the end.
One of these requirements has to be chosen:
sink in a certain way
stay dry
build without engineering and see what happens
Maximize Attention
Round Cardboard Boat ... liquid nail sealed with contact cement
These are situations that don't maximize attention:
Boat rolls over at the dock, dumps everyone in the water and instantly becomes soaked in water
Boat design is too heavy and can not be carried in the parade in front of the judges. Want boat to sink in front of the judges, not be abandoned at the end of the race.
Boat takes on water, doesn't sink, but becomes too heavy.
Then there are the boats that invite ridicule because they don't go anywhere. Round boats may be easy to defend in the demolition phase, but offense requires chasing down the enemy. Round boats that only spin in circles usually win a futility award.
A crew
Team moving very heavy cardboard boat.
Building a boat without a crew that is ultimately going to paddle it in a competition is an invitation to disaster. The crew needs to
train if the boat is going to be fast
willing to get wet
practice carrying the boat in the parade
practice getting in and out of the boat without tipping over
Transportation to the Site/Expect Damage
How are you going to Move It?
moving on top of car
Using boat trailer
Moving onto flatbed truck
Expect damage .. and plan on fixing it
Demolition or transportation to storage
Most boats will be demolished. If the boat is to be saved, a crew is needed to transport the boat to storage. Timing is critical. The race organizers typically demolish most boats. Saving the boat requires planning ahead.
Bottom of cardboard boat after being in the water about 5 minutes and then dragged
automatically hauling boat to a dumpster .. guy in the boat has shifted it's center of gravity to on top of the truck's bed :

## Design

* There is free software for hull design here. Need to install windows xp mode to run it.
* Lots of build pictures and video are below
Draw the Boat
Stretched hat boat drawing in Pro/E
Most programs such as sketchup have rulers. There are pre-drawn boats at 3D Warehouse. A ruler in sketchup can be used to cut the cardboard to the correct dimension. Autodesk Inventor can compute the center of gravity once drawn.
Make models of the boat
Can use models to raise money
Origami Boats
Dragon Designs
Corrugated Fiberboard Sources
Retail
Cardboard boxes are used everywhere. But they can not be found because they are compressed into a steel box by a compactor. Asking a retail store to not put boxes in a compactor causes problems because usually have no where to store the boxes. Refrigerator boxes are the best for building anything. But to get the box one has to hang around a store where refrigerators are sold.
Dumpsters
Cardboard is recyclable. Some institution have dumpsters dedicated to cardboard that are not baled or compressed. These boxes are typically smaller in size. Big boats become more difficult to build without large boxes. The best boxes in these dumpsters are usually related to computers and electronics.
Donations
Corrugators are machines that make cardboard sheets that are 7 feet by 8 feet approximately. Around major cities there are companies that install and repair the machines and companies that operate them. Cardboard is cheaper to make locally from recycled pulp that it is to make centrally and ship. Cardboard is very much like concrete in this respect.
Don't say Cardboard
The best source of donated cardboard is a company with a corrugator. They typically have a loading dock, ship lots of stuff and are generally willing to donate sheets of corrugated fiberboard. Talking to them on the phone is difficult. If you say, "will you donate some cardboard boxes?" they will not know what you are talking about. Cardboard boxes are made of corrugated fiberboard. The term cardboard means too many different things. Expect packaging engineers and technicians to be immediately confused if you ask for a cardboard box. They will not understand what you are asking for. You are looking for "corrugated fiberboard sheets."
Cross Flutes
Flute standards have been relaxed since the corrugated fiberboard market has matured. There is no need to help organize it or protect consumers.
Corrugator Machine input and output
Walls
Flute Standards
Cardboard boxes are all different
Single Wall
Double Wall
Triple Wall
Overlap the Flutes
Starting point may be to glue two sheets together with flutes crossed
Flutes crossed
Since all flutes are in the same direction, is going to be strong in only one direction
Strength
Cardboard tubes are sometimes illegal in competitions
Cardboard boxes are designed to stack and not compress. The flutes all run up and down. The sides are normally subjected to jiggling during transportation. Conclusion:
strong up and down
weak sideways
Some engineers take a statics class and material dynamics class. There are three major points from these classes that apply to cardboard boats:
triangles are strongest (trusses)
computing centers audio of mass and buoyancy help prevent tipping
pulp is not wood
Think of wood as a massive number of straws that are made of chains of paper clips. Water gets into these straws like a water balloon. The straws expand sealing all cracks. A wooden boat seals itself. Pulp is like a bunch of needles glued together. Building a cardboard boat involves just adding more glue. Water dissolves most glue, so the boat is covered with a sealant. But the sealant is meant to keep out the moisture in air, not water itself.
Wooden boats can be left in the water years. A cardboard boat instantly leaks and should only be in the water for minutes. Cardboard dissolves like toilet issue. All other issues are secondary.
These papers are something a packaging engineer would read:
paper on honeycomb strength
Paper on crush strength.
Demolition
Air Pressure cannon designed to spray occupants so they want to jump in water .. video
The problem is that too many people build cardboard boats that don't sink. Yet they don't want to take them home, so they get thrown away without sinking. Fewer boats sinking means that the cardboard boat event draws less of a crowd.
Some event organizers have tried to add demolition derbies at the end. But boats crashing into each other and poking at each other doesn't sink boats. Most audiences are not patient enough to wait hours for cardboard boats to sink on their own. How else could boats be sunk and people forced into the water?
Swim underwater with box cutters
Spray people with tomato juice so they want to get in the water
Fire projectiles through the cardboard boats
This stimulated another project called "Air Cannon".
Dramatic Sinking
Cardboard boat sinking ... wining the "most dramatic sinking" award ... can see the garbage boat ready to pick it up ... at the end the rescue boat comes in.video
The boat should have a name and a story in order to win the award for the most dramatic sinking. In this case the boat was named "Free Ride" for having no crew because nobody wanted it. It was especially ugly and looked like it would sink.
Carrying Mechanism
Video of carrying a cardboard boat in a parade in front of the judges
The carrying mechanism should help get the boat out of the water without damaging it, and then continue to carry the boat in front of the judges. Think of a casket being carried in a funeral.
Decoration Support
There are usually "theme" awards. Some events have a design theme and awards are given that best match that theme. A hole can be drilled completely through the boat, filled with PVC pipe and then sealed at the bottom to create a place for a pole to be inserted later. Obviously, some planning was necessary for these boats:
doesn't have to be functional :
* Boat Building Pictures
One-Two Person Quick Build
Competitions held at a pool generally have the objective of racing in a straight line from one end to the other. Sitting in long narrow boats wins.
Competitions held on a lake generally require turning and thus the best boats are unstable .. hard to turn and go straight. This happens around 10 feet long with width of 30 inches.
The materials are typically cardboard, plastic and duct tape. Let the cardboard seams guide you. Wrap in a plastic bowl and tape to the cardboard.
Two Person Boats Built before the Race
Tiki made out of refrigerator box with contact cement build video test video competition video actually races the "pointy boat" documented next
pointy boat .. Testing video .. Competition video .. boat doesn't get a name, doesn't get painted a color .. some kids jump out and climb back in during the race
This boat was called "blue" ... it was just painted ... construction video ... testing video ... racing video
boxes purchased from an office supply store, contact cement and superglue boat build video ,, Failed Test Float Video
A box 1 x1 x 3 will float 180 pounds
Wide, flat Bottoms tend to be less “tippy” than V-shaped bottoms. One paddler, make 30 inches wide .. two 48 inches
Longer boats go faster, but they are harder to turn.
Boats shorter than 10 feet are difficult to steer straight.
10-12 feet in length seems to be just about right.
Don’t make sides higher than 18 inches.
The lowest center of gravity (sitting in the bottom of the boat) is the most stable
Kneeling or standing will tip over boats
Big Boats
Big boats carry between 3 and 8 people. They are typically more expensive than purchasing a real boat. Even the simple canoes have to be engineered. A group of people have to work together. There has to be a design. There have to be last minute decisions. They take up a lot of space while building. The gluing/drying rhythm requires working a couple of hours every day ... for many days ... at times drying for a week is necessary. Rain has to be dealt with. The dust and debris can fill trash cans. They lead to a desire to re-use them year after year.
Big boats can be fast and look like an olympic rowing machine.
A majority are slow and win "theme" awards. They are similar to floats in a parade. They can have mechanical aids such as ribs formed from electrical conduit, and bicycle parts turning a propeller or wheel.
Big boats are logistically hard to test. The construction pictures are the most interesting.
This boat was finished, named "Pollock" after the artist and raced video. It was not tested. The construction pictures are below.
This vide shows several problems .. the heat gun is causes the glue to turn into tube with a fluid core, liquid nail as a plaster, the bad fit of liner to the shell, and the use of paper bags did not seal the edges ... which then depends on the wall board sealant to hold the edges down.
This boat was constructed to have two people rowing side by side. It involved a lot of bracing. video
This video describes the construction of a round boat. It was never finished. It was cut in half and turned into two round boats, rather than a squirrel cage boat.
Pollock Boat
The 20 cardboard sheets were donated from two different companies. It is impossible to purchase cardboard sheets this big. They are strange sizes .. 6 feet by 7 feet .. and you don't want to fold them. So transporting them 70 miles on freeway becomes an issue. About $800 was spent in 2008 on wood glue, liquid nail, wall board sealant and paint.
Expense Detail
A school donated tools: tarp, box cutters, saws, screw driver, caulking guns, T-square, 8 foot straight edge.
Donated items:
OrganizationItemNumber
TimBar7' by 6.5' corrugated24
PCA7' by 6.5' corrugated24
SafeWaypaper bags10
Giantpaper bags20
Tools from school: box cutters, saws, screw drivers, caulking gun
ConsumablesCost
Rollers !!$15
Roller Brushes$15
Paint Brushes$20
Paint Tray$3
Tray Liners$3
Wood Glue$320
Contact Cement$30
Wallboard Sealant$210
Liquid Nail$84
Paper Bags$10
Paint$90
TOTAL$800
limo or stretch cab version of free ride ... link to free ride
model of free ride that was stretched
20 sheets of cardboard were glued cross fluted into 10 sheets and painted with wall board sealant .. sealant prevented warping while cutting
PRO/E drawing .. used measuring tape inside of Pro/E to decide how to cut the 10 cross fluted sheets
Four of these sheets were cut to form the bow and stern
Can see Eight pieces being put together to form outline of Free Ride .. but are going to become the stretch version .. Big Boat
The hump end caps have been glued together and all the edges cut at 45°
Both hump end caps have been glued and now the hump sides are being measured and cut.
Hump tent has been glued together. Liquid nail has been applied to the surface that is going to be glued to the hump end caps.
The nose pieces were glued together and leaned against a chair and the tent to dry
Getting ready to glue the other nose on.
Gluing sides on
Finished gluing both sides on
The deck is going to be very narrow .. 5 inches .. planning how this is going to work
Deck is going to be formed by a pair of triangles .. both outside the tent and inside the tent .. outside triangle is 8 layers thick
Some bracing was added around the hat and the side walls were trippled. Then the boat was lifted up on to four tables.
This is what the boat looked like underneath. The goal now is to add some bracing underneath.
The triangles used for the deck also have to be put inside the dome.
A Triangle for inside the dome drying. Duct tape and wood screws failed. Had to use the bricks.
Brace was added inside the tent, because people are going to be leaning on it while rowing
Deck triangles added inside the tent
Birds nest built in triangle overnight
Applying liquid nail to outside of triangle before creating deck
Padding outside of boat so that bottom will fold up onto an even surface
Padding outside to prepare for the handrail
Bottom being added
Bottom added
Closeup of the bottom seam
Screws removed and holes plugged up with liquid nail
Bottom Seam
Bottom Seam covered up and painted
Screws holding handrail together while drying
Detail on the hand rail .. can see that in one section it is 14 corrugated flutes thick.
Boat was painted and named Pollock after the artist Jackson Pollick
Bow and Stern decorations were added :

## Implement

Safety
Wear a life vest, even if you know how to swim
initial water on cardboard
water soaking into cardboard
cardboard dissolving where water was dropped
Every lake, pond, stream has someone that is responsible for it. Ask permission ... or forgiveness
Cardboard boats can be light, but still very awkward to carry .. especially up and down hills to lakes
Don't get stranded in the middle of the water
rocks can poke holes in the bottom of the cardboard boat
Tools
Smashing Cardboard together with weights while glue dries
Bricks to hold cardboard sheets together while drying
Chunks of concrete to hold cardboard sheets together while drying
Need indoor and outdoor space to glue .. because it rains often in the spring in some places
Liquid Nail
Caulking gun for liquid nail
need cases of liquid nail .. it is least messy coming out of a caulking gun
Cutting
knife to cut cardboard .. always cut ontop of another cardboard piece or wood in order to not damage the surface below or dull the knife
a small rotary saw .. even battery powered .. makes cutting straight lines and fitting cardboard pieces together much easier
Drawing long straight lines and cutting through them is almost impossible without a good straight edge
A T-square is good for creating right angles, but not good as straight edge
Ideally have a drawing with dimensions that need to be transferred to the cardboard and cut
Cut pieces of the boat ontop of another sheet of cardboard or piece of wood to prevent damage to the pavement and the blade of the box cutter
Spreading Glue versus Painting
Gloves to keep liquid nail and wood glue off one's hands .. can spread the wood glue with these gloves on
paint brushes for applying the wall board sealer and paint, don't use to spread glue
The white buckets in the back hold wall board sealant
Paper Towels for Cleanup
Holding Cardboard together while drying
Wood screws of various lengths to hold cardboard boats together .. screwing through layers soaked in wood glue or wood pieces creating a press
Clamps holding cardboard together while glue dries
Drill instead of screw driver when using wood screws to press carboard pieces together while glue dries
A wood pallet can have very hard wood .. so hard that it grabs screws really hard and can really press cardboard together while glue dries
Most types of tape, including duct tape are not that useful
Elevating cardboard while working on it
table to elevate boat so can get underneath it and paint
Saw horses are the triangular black pieces under a sheet of cardboard
Knee pads are useful, the hammer is not, the level was not used
Tarps
Tarp protects ground from wood glue being spilled
Tarp protecting stack of cardboard boxes being used for constructing boats
Tarps should be huge
Wax paper is like a miniature tarp, but practically no glue sticks to it .. so use it ,, instead of tearing up a tarp
Forms Jigs
A Jig is a temporary tool used on a material to bend or hold in place while something happens to it .. then the jig is removed. This is the jig that bent the conduit used in build the round boat
Here an old fence?? was used to lift the round boat off the ground so it would not come in contact with rain water when the tarp was over it
There are many ways to hold cardboard in place ...
Screws can create threads in corrugated fiberboard that has been soaked in wood glue and then dried .. but is not very strong ... threads rip and strip
Clear duct tape works well to hold together while glue is drying. It is hard to get the duck tape off without peeling off cardboard. So often it is left on the cardboard.
Use bricks to hold sheets of cardboard together while the glue dries
Here two pieces of wood connected by a wood screw are pressing sheets of cardboard together while drying ..
clamps
Leaving screws in a boat can result in sharp wood screws appearing while sinking and cut people.
Gluing
Liquid nail dries quickly (hours) but is expensive. Liquid nail advertises that it can close a 3/8 inch gap.
purchase liquid nail by the case
Picture of woodglue brand
ContactCement is expensive
Gluing without a tarp underneath will always put glue on the concrete underneath
Don't pour wood glue on a boat to solve problems, but do pour it on cardboard sheets and then spread it quickly ... or it is absorbed .. it disappears
Liquid nail can fill 3/8 inch gap ... anything thicker causes problems
Can spread the wood glue a variety of ways
spreading qood glue with cardboard
a heat gun may cause wood glue to dry faster
Picture of woodglue brand
Wood glue dries (days) but is cheap.
All other forms of glue are either expensive or not strong enough.
Gorilla glue is good for quick repairs when the boat is wet during competition day .. otherwise don't use .. it foams up and requires moisture to cure
Apply thin coats of glue. Do not pour into crevasses and form puddles and expect it to harden into a block. Wood glue can form a hard shell with a liquid interior that is both not very strong and can explode into a mess.
Paint the glue on.
Sealing
Cardboard is a lot like dry wall or Gypsum board.
rollers are used on large flat surfaces, paint brushes on inside corners, expect the inside corners to take more time than the big flat surfaces ... many thin coats dry quicker and more evenly than one thick sloppy coat that takes overnight to dry
woodglue dissolves in water and soaks into the cardboard .. it is not a sealant .. using the same paint tray for both purposes is possible, but it is better to use liners
Papertowels encourage people to clean up .. no paper towels guarantees a mess
Skinning the boat with paper bags
This boat is being sealed without being skinned .. skinning adds a layer of protection from water .. less likely to sink
partially skinned boat .. was sealed prematurely .. this is why there is white underneath the paper bags ... no need to do this ... sealing twice doesn't add that much protection
dip paper bags in glue in a paint tray, then apply like wall paper, smoothing out the bubbles .. liquid nail can not substitute .. it leaves lumps
Sealing
Contact cement can be thought of as both glue and sealant
Drywall sealant is the best
There are different brands of drywall sealant
Painting
paint on top of sealant
Another picture of paint on top of sealant
Testing Corrugated Fiberboard
The goal is that cardboard boat doesn't collapse immediately during Float Test
This is traditionally done with ribs shaped like a U
The question is how to best make the U shapes
Corrugated Fiberboard is strongest when under compression in the direction of the ridges of the flutes
a lot of weight could be put on top of this column
triangle columns work too
the best way to test beams is to hang weights in the middle
Looks like triangles are the strongest
And they can be very strong
Cleanup
Garbage boats clean up lakes .. expect cardboard to float for a while after the boat sinks ...
Cleanup of the work space cardboard debris is easy. It is the paint/glue/wallboard sealant mess that can be impossible. Chemicals, pressure washing don't work. Scrapping can damage the original concrete finish. Make someone responsible, give them tarps, work on grass as much as possible, plan small thin coats rather than one big thick coat.
Pouring glue into cracks is the single biggest mistake. One doesn't want to move the boat, tries to put it in storage position, and the tarps always spill liquids .. plan on it.
wood glue always gets on shoes which then gets on the concrete
wood glue should never be poured into a crack ... to fill the crack ...
Gluing without a tarp underneath will always put glue on the concrete underneath :

## Operate

A typical competition involves races and parades. In some competitions, the rhythm is to race the boat in pairs, carry it back to the starting line and race again in tournament. In other competitions, everyone pushes off the shoreline at once.
There is usually a MC making announcements and a panel of judges that are continuously commenting on the boats. The judges typically start with a narrative supplied (or not supplied) by the builders. The judges run around the docs organizing the races.
The races identify the fastest boat through heats like a swimming meet. After all races, there is typically a demolition derby. Announcements at the end give out awards in other categories .. most dramatic sinking, most futile, most dramatic sinking, best of a theme, judges awards, etc.
Race Details
Parade
Getting ready, can see judges tent
Everyone that might get wet is in a costume and walks in a parade
The sponsors of the event start the parade
an actual race route from satellite photograph green is the parade route, red is in the water
Water Route
The loading dock is where the boats are launched ... here two at a time .. sometimes this is a beach and everyone launches at once
Buoys mark where the path the boats take .. here the goal is to keep the buoys on the left of the boat .. some courses have a straight line and race back and forth between two beaches
The finish line here is hidden behind the trees of most of the audience and judges .. this is because getting out of the boat is where lots of damage is done and people try to stay dry getting out of the boat
boats are raced in pairs, sorted into heats like a swimming meet, they race over and over again until there is a winner and then the boats that are still floating try to sink each other :

## Demo

Presentation

## Next Steps

* Build established boat designs using corrugated fiberboard
* Use old fiberglass forms to build corrugated fiberboard boats
* Develop questionnaire for those requesting a boat be built that focuses on how the people want to get wet.
* bad engineering
* bad planning
* demolition derby
* planned failure mechanism
* unknown planned failure mechanism