Class teaches how make a milk carton boat that floats

Now that the Portland Rose Festival Milk Carton Boat Regatta returns on June 7, see what would-be pond-sailors are learning from milk carton boat building experts. And, you’ll find the official rules and boat-building tips right here  …

Instructor Sue Bunday, the President-Elect of the Portland Rose Festival Foundation, explains that boats need to be wide enough to not capsize while the captain paddles.

Story and photos by David F. Ashton
If you’re planning to enter the 2009 Rose Festival Milk Carton Boat Regatta, which returns after a long hiatus on June 7, experts say you can’t start designing and building your boat too soon.

Sue Bunday, President-Elect of the Portland Rose Festival Foundation, has been teaching classes around Portland. Her husband, Dennis, a milk carton boat designer and builder with 17 years experience, came along to help out at several of the “boat building” classes they’ve been offering around the Portland area.

“We have six children,” Dennis told us. “One of the first ways we got involved with the Portland Rose Festival was to build a milk carton boats for our Cub Scouts and the Girl Scouts about 17 years ago. We loved entering the races.”

With the boat races finally being revived, Dennis said, the Dairy Farmers of Oregon and Portland Rose Festival Foundation needed someone with “institutional knowledge” of, and practical experience in, craft construction.

Instructor Sue Bunday, and her husband Dennis, built and raced their watercraft in the Portland Rose Festival Milk Carton Boat Races for 17 years.

Cartons and jugs provide the float
At the session, we learned that the boat can only be a maximum of 8 feet long. The only floatation material allowed in making them are milk cartons or jugs – no Styrofoam, inner-tubes, or inflatables allowed.

The first step is to make sure the containers are empty, clean – and tightly sealed shut with a good-fitting cap or hot-glue.

How many jugs does one need? “It depends on how much – including the boat, passengers, and decorations – all weighs in total. We call it ‘milk-carton math'”.

  • A one-gallon plastic jug floats 8 pounds of weight;
  • A half-gallon paper carton floats 4 lbs.; and,
  • A one-quart carton will float 2 lbs.

So, this means that the 40 plastic jugs that participants received from the Dairy Farmers of Oregon after the class will keep 320 pounds afloat. If your watercraft’s frame, deck, jugs, and crew weighs 600 lbs., you will need 75 one-gallon jugs or 150 half-gallon cartons to float your boat.

Preventing a tipsy canoe
If your boat is narrow, and the crew sits high above the water line, there’s a good chance it will become unstable and capsize. Most successful participants design their boats as a catamaran, or build it with outriggers. Tall superstructures or sails – make-believe or otherwise – may catch the wind, and push your boat off course faster than you can paddle.

Unless you have a sophisticated machine shop and considerable engineering skills – avoid paddle wheels or propeller systems! Since “human power” is the boat’s only allowed propulsion, stick to paddles.

Want to know more? Visit for more details about the Dairy Farmers of Oregon Milk Carton Boat Races, and get real-time updates on Twitter by following @MlkCartonRace09.

Official rules and tips are below!

Errol Heights residents Kimberlee Padgett, and her daughter Emily, get a load of ready-to-use one-gallon jugs from Natalie Caminiti with Dairy Farmers of Oregon, after taking the boat-building class.

Dairy Farmers of Oregon Rose Festival Milk Carton Boat Race
Official Rules

A. All participants must wear U.S. Coast Guard approved life jackets while in the water. Ski belts are not acceptable.

B. Vessel must be made by the participant with flotation dependent upon milk cartons/jugs. Waxing, shellacking, or covering hulls with materials such as plastic, lamination, or metal is not allowed.

C. Vessels must stay inside their designated course during the race. Crossing lanes will result in disqualification.

D. Vessels should be no longer than 8 feet in length.

E. No engines or motors of any kind are allowed. Propulsion power or any other kind of stored energy is also prohibited. This means human power only!

F. Any propeller or mechanical devices must be covered by a protective enclosure.

G. Vessels must keep the same design for all events. Additions or changes to boats during the races will result in disqualification.

H. Nothing is to be thrown or released from boats while in water. Violation results in immediate disqualification.

I. Each vessel will be inspected prior to the race to make sure that it fits within the rules and safety guidelines outlined on this sheet. Any boat not built according to the Dairy Farmers of Oregon rules may be disqualified.

J. The Dairy Farmers of Oregon will provide boat builders with 40 number of milk jugs at specific locations and times, to be listed on the website. Any other materials beyond what is given are the responsibility of the participant.

K. Participants may choose to compete in one of five speed race divisions:

a. Children (7-12)

b. Adults (13+)

c. Family/Multi-rider (parent with small child)

d. Corporate (including businesses, non-profits, and loosely-affiliated groups)

e. News Media

  • All vessels may enter the “Show Boat” division, which will be judged prior to the first division speed race.

L. Participants must be present to win prizes.

M. We reserve the right to cancel any such race due to lack of participants. Participants whose race gets cancelled will be placed in next-best race division.

N. Vessels are only allowed in the casting pond during designated times. Any violation will result in disqualification.

O. Participants are responsible for the transport of their vessel to and from Westmoreland Park on race day.

P. At the end of race day, racers are encouraged to place their milk jugs in on-site recycling bins. Frames can be reused year after year.

Boat-making Helpful Hints

  • Both plastic jugs and paper milk cartons may be used.
  • Wash/Clean containers and make sure they are dry before sealing.
  • Save lids for plastic screw-top containers, and seal milk jugs/cartons with hot glue to avoid the lids popping off during racing.
  • Duct tape is a great way to secure your jugs/cartons to the frame.

Weight calculations for containers are as follows:

  • ½ gallon is equal to 2 lbs.
  • 1 gallon is equal to 3-4 lbs.

Don’t forget to subtract the weight of the frame, décor, and person(s) operating the vessel.

Follow these instructions to make a basic frame:

Supplies needed:

  • 3- 1″ x 4″ x 8′ boards
  • Wood screws
  • Screw driver (power is recommended)
  1. Cut 1 board into 4 equal lengths.
  2. Place two 8′ boards parallel to each other, approximately 20″ apart.
  3. Using the 4 pieces, attach one board at either end with wood screws, keeping them 20″ apart.
  4. Attach one board mid-length as the seat and the final board 14-18″ in front of seat board.
  5. Finished frame will loosely resemble a rectangular ladder
  6. Make sure milk cartons are tightly sealed shut using hot glue; that jugs are tightly capped.

Tightly secure each milk jug/carton to the frame by wrapping duct tape completely around both. General rule, if in doubt, tape it up!

General hints and suggestions
Kayak paddles work best for paddling.  You may also tape two paddles together.

Keep in mind that larger boats will need more jugs/cartons in order to float.

For floatation, your vessel must rely completely on milk cartons/jugs.  Above the water line you may decorate however you choose. Be creative! You may use glue, nails, tape, or other construction materials. Be sure, however, that they are fastened securely to your vessel.

Finding milk jugs/containers may be your biggest challenge.  Ask your friends, family, and neighbors to help you.  Other great places to find milk jugs/cartons include coffee stands, restaurants, hospitals, cafeterias etc. Ask for their empty containers.

Do a test run. When testing, look for flooding, breaks, cracks, and stability in the water. Then make changes accordingly.

Helpful Hints for Race Day

  • Wear a Coast Guard approved life jacket.
  • Bare feet are fine, but water shoes (aqua sox) are a good idea, too.
  • Bring lots of towels.
  • Reuse and recycle. The frame can be used in years to come, and the jugs/cartons can be used for many other projects as well.

One vessel, if securely made, can be used in different race divisions for more than one person.

© 2009 David F. Ashton ~ East Portland News

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