While the idea of submarines has actually been around since 1580, the first practical submarine that was able to sustain itself underwater for extended periods of time is actually a fairly modern invention. These submarines are what people think of when they hear the term "submarine," and they can be recreated easily in craft projects.
Recycle old cardboard boxes by creating a colorful submarine playhouse for your children. Use a large refrigerator box for the main body. Wrap the sides of the box in aluminum foil or a metallic scrapbooking paper. Cut three large holes in the side for the portholes. Leave either end open. Paint a cardboard bin with acrylic paint for the top of the submarine. Cut a hole in the sides of the box for portholes and a small hole in the top for the periscope. Cut a large hole in the top of the refrigerator box so your child can stand in his submarine. Use a PVC pipe to create the periscope and lay down pillows inside the submarine so your child can lay in her vessel.
Create a bath toy with a couple of empty plastic bottles. Cut the top off of one bottle and the bottom off another. Use tape to secure the bottles together and seal the edges together for a smooth finish. Cut the hole into the top of the bottle and insert the neck of a spray bottle and tape around the neck of the spray bottle for water sealing. Attach a black milk cap to the top of the threaded squirt bottle. Cut propeller blades from the scraps of the plastic bottles and attach them to the bottles on one side. Put a little bit of water into the bottles and paint the exterior of the bottles gray with some submarine details. Put it in the bathtub and watch your children play.
Create a craft modeled after the Beatles' "Yellow Submarine." Use a clean and empty 2-liter bottle for the body of your submarine. Cover the plastic in yellow duct tape. Stick two pieces of black electrical tape together so that one slightly overlaps another and cut a circle from the tape. Cut a hole from the top of your bottle and insert a yellow plastic cup with the bottom facing upward for the periscope. Put a little bit of water into the bottle before gluing the lid onto the bottle so that the submarine can be used as a pool toy.
Use paper to create a window decoration that catches the sun. Cut a basic submarine shape out of a piece of construction paper. Have your child doodle on the shape with crayons or markers. Cut circles from the center of the submarine for portholes. Cut small squares from tissue paper and tape them onto the back of the paper submarine so that the porthole is completely covered. Make circular rings from the tape and place them on the paper of the back of the submarine and stick it to the window. The sun's rays will shine through the tissue paper.