Where can I find detailed resources on how to build a raft?

Creating rope from natural sources is going to be a tremendously labor-intensive process, requiring "desert island" levels of free time. And it will require a surprisingly large quantity of the source material. For example, yucca plants were used for cordage here in the Southwestern USA, but I would need a small yucca farm to get enough cordage to build a raft. Taking yucca from local parks/open spaces would be illegal and create a real eyesore. Perhaps you could use rawhide cordage instead? But it tends to weaken and stretch and tear in water.... Frankly, I think you have to let yourself buy the rope. But in case you're stubborn enough to try making your own, here is http://www.instructables.com/pages/search/search.jsp?cx=partner-pub-1783560022203827%3Anpr2q7v5m6t&cof=FORID%3A11&ie=ISO-8859-1&q=cordage. Once you have cordage, you need something to lash it with. Thor Heyerdahl sailed a balsa log raft from South America to Polynesia, as zinon mentioned, but where are you going to get balsa logs? I suspect that the easiest material to come by for the main components would be bamboo. If that's not possible, you want the http://www.engineeringtoolbox.com/wood-density-d_40.html possible. Once you have wood and rope, you need to understand http://makeprojects.com/Project/The-Lost-Art-of-Lashing/955/1. And once you've created the basic structure of your raft, you need to have a way to make it go where you want it to. You might want to look into the http://www.simplicityboats.com/yulohpage2.html, or oars and http://www.boatdesign.net/forums/attachments/boat-design/53017d1296136851-rowlocks-rowing-boat-pin.jpg. (An oar, paddle or yuloh can be a flattish piece of wood -- shaped with a stone adze? -- lashed onto a branch, it doesn't have to involve store-bought lumber.) I would advise against relying solely upon sail for getting around on your raft, as that will only give you the ability to go downwind. Hull shape is essential in sailing in any other direction, and if there's one thing you won't have, it's hull shape. Good luck, and let us know if you survive the experiment ;^)

The American Boy's Handy Book, published in 1890, is full of plans and construction techniques for all kinds of things, including rafts, to be built with little more than an axe and a good supply of apple pie. There is http://openlibrary.org/books/OL7244601M/The_American_boys%27_handybook_of_camp-lore_and_woodcraft available for free on archive.org but it looks like an early version that did not include the raft instructions. The versions http://www.amazon.com/exec/obidos/ASIN/0804839956/metafilter-20/ref=nosim/n (and visible through look inside) do include the boat/raft chapter.

You may need to add googleable terms like "survival" to your terms, or "wilderness" I found http://www.wilderness-survival.net/crossing-2.php which looks like it's what you are looking for. There's some other http://www.wilderness-survival.net/forums/showthread.php?18302-Hand-made-raft in the forums.

Here is a cool http://www.chineblog.com/2009/02/thinking-about-a-ocean-voyage-on-a-bamboo-raft/ made out of bamboo. A google search using "bamboo raft building" led to nearly 5,000 hits. Bamboo seems like a very logical thing to use as it's easy to find and a lot easier to move around by yourself than logs. Most everyone I know who has bamboo growing in their yard is happy to give some away if asked as it tends to spread.