Tips from Holly Frohloff to help you prepare for HYC’s 1st Annual Cardboard Boat Race Saturday, August 15th
1. To float, your boat must displace enough water to support its weight and the weight of the crew. One cubic foot of water weighs about 60 pounds so if your boat and crew weigh 300 pounds your boat must displace more than 5 cubic feet of water (300 pounds / 60 pounds per cubic foot = 5 cubic feet). For width, figure about 48” maximum for 2 people.
2. Any extra cubic feet your boat has will allow the sides to stick up above the waterline (this is called freeboard). Some freeboard is necessary to prevent the boat from being swamped by waves. However, on a windy day, too much freeboard makes it difficult to control the boat (wind blowing on the exposed sides acts like a sail pushing the boat off course). Allow about 18” for you to sit and paddle effectively without the edge of your boat blocking your arms.
3. It is important to strengthen the boat against the water pressure that will push in on the sides and bottom of the boat. You can reinforce your cardboard hull by using more than one layer of cardboard with the waffled inside “grain” of the layers set perpendicular to each other (for example, one layer vertical and the next layer horizontal). It will also help to brace the hull with rigid pieces to keep the sides from collapsing.
4. Even a well-designed boat will quickly give way if water gets to any part of its cardboard structure. Overlapping seams sealed with waterproof glue or tape will help keep water from seeping in at the edges. The exposed surfaces of cardboard must also be coated – just be sure the paint you use is waterproof and water-soluble. Consider coating the inside of the boat as well as the outside of the hull. Water is almost sure to splash in and a boat can collapse from the inside just as quickly as from the outside. Note: duct tape shrinks when it’s painted and clear tape melts when it’s painted.
5. In general, a long narrow boat will go faster and straighter than a wide boat and a boat with a pointed bow and stern will go faster than a boat with a flat bow and stern. Longer boats go faster but are hard to turn; a wide boat is easier to maneuver and is not as likely to tip over. Flat-bottomed boats are more stable than V-shaped bottoms, unless the “V” is very wide. Also, a boat with a low center of gravity is less likely to tip over, so keep weight (including the crew) from sitting up high in the boat.
6. A boat that is symmetrical and balanced (both side-to-side and fore-to-aft) will move more smoothly and handle more predictably than a boat that is off-kilter.
7. Finally, remember that boat-building is a series of trade-offs. Experiment, be creative, and most important of all…HAVE FUN! J
NOTE: search “cardboard boats” on the internet for further information
