http://www.hardscrabblefarm.com/vn/poncho.html The Poncho From FM 21-15, Care and Use of Individual Clothing and Equipment, January 1966 Chapter 3 BIVOUAC EQUIPMENT 13. Poncho The poncho, with hood, is made of coated nylon cloth and is waterproof. It is roughly rectangular in shape with the long sides parallel and the short sides slightly curved. The hood and the opening for the neck are locate..