It's not terribly difficult to make a boat that can float. For a quick, easy boat project, there are plenty of everyday items that can be substituted for parts of a boat: the only limit is your imagination. For more involved, longer projects, you may consider boat kits, which provide all the necessities for making a finely detailed floating boat.
An easy, cheap, and fast way to make a small boat that floats requires a small foil loaf pan, soft modelling clay, scissors, a wooden or bamboo kebab skewer and a flexible vinyl or plastic report cover. The foil pan should be pinched to shape the bow of the boat, and the report cover should be cut into a triangle shape. After folding the triangle in half, with the point of the top touching the flat bottom, poke a hole roughly 2.5 cm (an inch) from the top and bottom. The skewer should be put through both holes, and the base of the skewer affixed to the bottom of the pan with the modelling clay.
There are many patterns for folding an origami boat -- in many cases, with the right material or a simple treatment after folding, a paper boat will indeed float. Though it's possible to make an origami boat out of standard paper that will float, the problem is that it won't float for long. Instead, try making an origami boat out of foil -- being careful not to tear the hull -- or you can apply a gentle waterproofing spray to an origami boat made with paper.
Juice box boat
A used 2 litre (1/2-gallon) orange juice box can be used to make a floating paddle boat with only a few modifications. Working lengthwise, cut the juice carton in half, cutting the top from one half and sliding one section into the other to form a box. Tape chopsticks to each side, so they extend 7.5 cm (3 inches) beyond the back of the boat, and cover the whole boat in duct tape. For paddles, cut two rectangles of plastic from an empty dish or washing powder bottles and cut a snip halfway through the sides of each piece. Slide the rectangles together to make an X shape. Stretch a rubber band between the chopsticks and centre the paddle between its lines, taping the rubber band into position.
Model boat project
Sailing small model boats is a hobby enjoyed by many enthusiasts, and several retail craft and hobby shops sell supplies and kits for making seaworthy model ships. Hulls can be purchased made of either wood or fibreglass, and can be as large and ornate as the builder desires. These craft can be outfitted with radio-controlled engines and other mechanical components.