Catamaran

If you live within easy walking distance of a small lake you may want to build this project. A sketch of the model boat appears at the bottom of this page. You will need a saw, scissors, duct tape, string, a large plastic bag, six empty plastic soda bottles and wood. Also helpful are a couple of six penny nails(about 2 inches long), a serrated edge knife and a hammer.

The instructions here are for a model boat with a mast about 42 inches tall. Use a shorter mast and smaller sail if it will be used in a breeze. Otherwise the boat will tip over. 3 liter soda bottles are used for the hulls. Use 2 liter or 1 liter bottles for smaller sized boats. First cut the top and bottom off of 2 bottles. Use a sawing motion with a serrated edge knife to make a slit and finish with a scissors. Make a lengthwise cut the full length of each of the resulting tubes. Insert the bottom end of two more bottles each halfway into a split tube. This connects the two bottles bottom to bottom. Wrap duct tape around the assembly with half the tape's width on an end of the tube and half on one of the bottles. Do the same for the other end. That completes one of the hulls. Repeat the process to make the second hull.

Straight lengths of tree branches can be used  to build the rest of the boat. A diameter of about an inch will do nicely. You will need 2 pieces each 24 inches long, 2 pieces each 42 inches long and 2 pieces about 30 inches long. One of the 30 inch pieces will go along the bottom of the sail. It serves to keep the sail straight. That piece can be narrower than one inch. To help decrease sliding of the pieces of the boat, shallow notches can be sawed into the wood where one piece is connected to another piece or is connected to a bottle. .

Lay the two hulls parallel to each other and about 22 inches apart. Place one of the 24 inch pieces so its ends rest on the necks of two bottles. Lash the stick to the hull by wrapping the junction tightly with string. If you are using thin string or fishing line, use about 8 feet for each joint. In the same manner put the other 24 inch piece at the other end of the hulls.

Cross a 30 inch piece and a 42 inch piece so they touch at the middle of the 30 and two inches from one end of the 42. If you have a hammer and a six penny nail drive the nail through the two pieces. If not lash them together securely. These two pieces will be the mast(42 inches) and the sail yard(30 inches). Cross the free end of the mast and the other 42 inch piece(which we will call the center beam). They should touch about 1 1/2 inches from the end of the mast and 18 inches from one end of the center beam. The sail yard should be at a right angle to the center beam. That is they should appear to cross each other if you look down at them from above with the mast upright. Drive a six penny nail through that connection. Lash the joint with string whether or not you use a nail.  Next place the center beam so it crosses at the center of both 24 inch pieces. About 8 inches of center beam should extent at each end beyond the 24 inch pieces. Lash the joints.

To make the mast rigid heavy string is run from near the top of the mast to each of the hull ends. Begin by running the end of a piece of cord around both a bottle end and the 24 inch cross piece. Tie the end of the cord. Run the cord up to and around  the mast just above the yard. Knot the cord there so it won't slip. Continue that same length of cord to one of the other hull ends and tie it there. Run a second cord in a similar manner using the remaining two hull ends. Try to end up with the mast straight up and down and all the heavy cord tight enough not to sag. To make the yard rigid, again tie a string end to the junction of a hull end and a cross beam. Run the string up to and around a yard end and then down to a hull end. Then do the same thing on the other side of the boat. To keep the string from slipping along the yard either cut a knotch into the yard or drive in a small nail or tack.

Finally add the sail. Wrap the end of a string around the corner of a garbage bag. Use that string to tie that corner to one end of the yard. Tie the bag to the other end of the yard. Use the remaining stick tied in the same way to the bottom of the sail to keep the sail properly presented to the wind. Later you may add a kneel to the center beam to improve the boats tracking: perhaps a piece of aluminum siding, a couple of car license plates or even old phonograph records.