Challenge: The 100$ boat!

[dump-box]

Ok I hate to be a snot about this buuuut...Hypothetically if you had the time, the forest, and a chainsaw (or a timber saw by hand even), plus standard carpentry tools, a lathe (could be a really crude hand made lathe) a plane, Ax and Az, draw knife, and a few different wood saws, and a LOT OF TIME, I bet you could eventually make the HMS Bounty. You don't need any fasteners to build a boat, check out traditional Japanese construction method to carpentry or furniture construction. Actually, you could use hardwood pegs made from branch pieces in softwood (done right they are hard a nails).

Ok that aside, my cuz use to make all kinds of toys, when he was a boy, with pallets discarded behind stores. Both the timber and the nails were recycled into rafts, ramps, treehouses, forts, and a whole myrid of stuff. Art Center Design College had a design competition for the best furniture made from 1 wood pallet, and you wouldnt believe the great stuff those kids came up with. Looked like IKEA furniture you would buy!

That being stated, with enough time, creativity, and design, I'll bet you could make just about anything.

I have been kicking around an idea for a monohull (or a cat, or a tri) that would be like a traditional airplane (like a B-24 bomber from WWII) turned sideways, utilizing some mighty radical tech (by nautical standards anyways)
such as a self-trimming wingsail (see http://www.sailwings.net/article.html), coupled with a wind turbine assisted in a small necelle (just like a B-24 only further up the wingsail and a LOT bigger). Frankly, given the ridiculus amount of thing I've seen thrown away in my state, I'll bet I could salvage all the parts I'd ever need to build this for 100$ (if anybody wants to lend me a boatyard construction sight to find out let me know - might be there for a looong time though).

Course launching such a boat would cost a lot more then 100$. Hell I saw a tri sitting abandoned in a boatyard a few years ago. There literally was a bum sleeping in it. I'll bet you could get it to float for 100$. (regesteration and salvage claim fees gonna cost 100$ easly).

[dump-box]

Ok I hate to be a snot about this buuuut...Hypothetically if you had the time, the forest, and a chainsaw (or a timber saw by hand even), plus standard carpentry tools, a lathe (could be a really crude hand made lathe) a plane, Ax and Az, draw knife, and a few different wood saws, and a LOT OF TIME, I bet you could eventually make the HMS Bounty. You don't need any fasteners to build a boat, check out traditional Japanese construction method to carpentry or furniture construction. Actually, you could use hardwood pegs made from branch pieces in softwood (done right they are hard a nails).

Ok that aside, my cuz use to make all kinds of toys, when he was a boy, with pallets discarded behind stores. Both the timber and the nails were recycled into rafts, ramps, treehouses, forts, and a whole myrid of stuff. Art Center Design College had a design competition for the best furniture made from 1 wood pallet, and you wouldnt believe the great stuff those kids came up with. Looked like IKEA furniture you would buy!

That being stated, with enough time, creativity, and design, I'll bet you could make just about anything.

I have been kicking around an idea for a monohull (or a cat, or a tri) that would be like a traditional airplane (like a B-24 bomber from WWII) turned sideways, utilizing some mighty radical tech (by nautical standards anyways)
such as a self-trimming wingsail (see http://www.sailwings.net/article.html), coupled with a wind turbine assisted in a small necelle (just like a B-24 only further up the wingsail and a LOT bigger). Frankly, given the ridiculus amount of thing I've seen thrown away in my state, I'll bet I could salvage all the parts I'd ever need to build this for 100$ (if anybody wants to lend me a boatyard construction sight to find out let me know - might be there for a looong time though).

Course launching such a boat would cost a lot more then 100$. Hell I saw a tri sitting abandoned in a boatyard a few years ago. There literally was a bum sleeping in it. I'll bet you could get it to float for 100$. (regesteration and salvage claim fees gonna cost 100$ easly).

[ancient kayaker]

So, step up to the plate, mate!

[jpgilman]

Petros - All I can say is brilliant! I'm just finishing up a Yost kayak with my kids and my daughter wants to build a sail boat. Last night it hit me that I ought to be able to take plans for any lightweight boat and go the SOF route. I think you and Brian Schulz at Cape Falcon make a pretty convincing case. Couple of questions about construction

14' is about what I had in mind. You suggest 3/4" stringers for a 10' boat, what were the scantlings of your boat? It looks like you lashed the stringers to the ribs, did you use any adhesive? Finally, anything you would change in hindsight?

John

Originally Posted by Petros

You can take any small boat design you like that uses flat panels (hard chines) and covert it to skin-on-frame construction. I just took the dimensions of a high performance sailing dingy and scaled them for my hull shape and built it just like a skin-on-frame sea kayak. For a boat under 10 ft you can get by with gunwales and a keel of about 3/4" x 3" and stringers of about 3/4" square. You can use plywood to make frames, or do like I did and steam bend ribs with plywood frames about every 2 feet to help hold the shape.

[ancient kayaker]

A skin-on-frame boat is about the only way to do a boat larger than a canoe with store-bought materials. My next boat will be starting shortly, a tiny 10' sailboat, but even at that small size and half-price marine ply (the supplier had a flood so it's water-stained) and my cheap instincts it's going to come in above $100.

JP: I suspect a SOF boat has to be more flexible than a ply boat in order to absorb shock, as the overall strength is less. Therefore it may be a good idea to use just lashings. Lashings can be seen in the photo of Petros' boat. Glue in the joint would stiffen it up so that a heavy impact might break a structural member. There's a nice SOF boat taking shape in this thread, it has reached the rib steaming stage and is worth following:- http://www.boatdesign.net/forums/woo...-new-post.html

[Petros]

Originally Posted by jpgilman

Petros - Couple of questions about construction

14' is about what I had in mind. You suggest 3/4" stringers for a 10' boat, what were the scantlings of your boat? It looks like you lashed the stringers to the ribs, did you use any adhesive? Finally, anything you would change in hindsight?

I used the lines from a one-design racing sailboat called a K-18, and scaled them down to 14', and I made a few minor adjustments certain dimensions to increase the free board height, transom, etc and it is now a hard chine design.

I do not think I would change anything, other than perhaps to make it lighter (I can heft it on to the top of my car alone, but if it was a bit lighter it would be even easier). It takes more time to remove unnecessary weight to optimize each piece without affecting strength, so I am not sure I would want to take the extra time. I might do some of the hardware details different, but what I have works just fine. I have altered the main sheet several time until I was happy with how it worked (simple is best!), and messed with the jib shape several times (part of sorting out the rigging really), but the hull has been unchanged except I put in better cedar floor boards from what I first used (not shown in these pictures).

It uses 1x4 (3/4 x 3-1/2) for keel and gunwales, and 3/4" stringers, and I am happy with the strength. the keel and gunwales are glued and screwed through gusset blocks to the frames every 2 ft, the screws were installed "wet" with Tightbond III glue. All of the stringers are lashed with polyester lacing cord (do not use nylon-it stretches too much and it works loose).

A light weight skin-on-frame will flex more than a hard shell and I think the lashed joints are stronger than glue or even screws anyway, and allow some flex without risk of splitting the stringers. They are also faster to make than counter sunk screws. Despite the light weight and flex, this type of hull is much more damage resistant than a hard shell, the flex absorbs impacts and reduces peak impact loads. The redundant stringers are also "fail-safe", a broken stringer or two, or even a cracked keel do not affect sea worthiness, so you can put off repairs until it is convenient. The slight flex makes the ride a little more controllable in rough water too.

I built it almost the same way a skin-on-frame kayak is built, I added the frames to stiffen it since there are not deck beams in the cockpit area. And I worked out a way to end the stringers and gunwales on the transom using triangular gusset blocks and screws/glue. I used no plans, just built to the scaled dimensions and work out the fit of each part as I went.

[jpgilman]

Makes perfect sense. Thanks

[boating4fun]

I don't think it would be fair to post a time limit on it but instead allow a 3 month or 90 day time limit that way people could work on their boat project and still focus on day to day daily living. also I think it would make sense to allow people to post a pic of not only their boat project but also a pic of their receipt showing how much they spent on their project... perhaps one could also use salvaged or restored parts like motors, steering console, hull and what not