junk rig catamaran made from plastic bottles?

[whitepointer23]

Originally Posted by HakimKlunker

I would like to study THIS stuff a little more. Is there a link?

google wetseal.com and you will find our website, look at envirocoat water proofing membrane. this one is made by wetseal for us franchisees. but there are several companies that make the same type of products.

[HakimKlunker]

I googled, and found the site below.
Looks good.
However: The only Latex membrane coming into my mind was NOT for boats...

(Found the correct link later, of course. Thanks for BOTH links...)

[whitepointer23]

Originally Posted by HakimKlunker

I googled, and found the site below.
Looks good.
However: The only Latex membrane coming into my mind was NOT for boats...

(Found the correct link later, of course. Thanks for BOTH links...)

that looks more interesting than our site

[MAINSTAY]

HakimKlunker
Yes, shape and strength are related. Plus part of the overall strength of a 2-liter bottle is the internal pressure of the carbonation. It puts the plastic in tension. It takes less material to resist a tensile force than the same magnitude of compressive force. And the 2-liter bottle has probably been engineered to the mil to handle all the shipping and storage abuse they get. They are tough units.
Could heat rather than glue be used to fuse your 'hull plates'? Is edge-to-edge fusing possible, or must an overlap be used? And wouldn't the fused 'hull plates still require internal ribs and beams? If the ribs could be made of bottles, this is a go. One suggestion that could be used for curved ribs and straight beams was that one end (top or bottom?) be cut off and the opening be glued to (bottom or top of) next bottle, forming long tubes with internal bracing (the uncut top or bottom).
LMo

[HakimKlunker]

I use plastic bottles each day and must say that gas pressures inside never crossed my mind. We can be quite blind at times...
I wonder how 'gas-proof' the lids are on long term or if there is a need for additional sealing.

If one goes to the extent of cutting, fusing and 'bottle framing' the boat, it certainly becomes very labour intensive.
To be cleared still will be the structural strength of such a construction and so it would make sense to first set up a series of tests to extract relevant data.

If this is the way to go, we meanwhile added to mere bottles: gas, a gas filling equipment, glue and/or energy plus a fusing/melting tool.
At some point all relative advantages towards conventional boat building will perhaps be eliminated.

[whitepointer23]

if you pressurize the bottles they might blow the caps off on a hot day.

[HakimKlunker]

Jet Drive!!!!
Let the caps face aft....

[MAINSTAY]

Whitepointer23
And if you don't pressurize them they collapse too easily. There is an optimum presure here.


Also someone posted that the tops can unscrew. So they glued them on. I accept a little adhesive-sealant as an excellent solution to both problems.
LMo

[brian eiland]

...not exactly my idea of a 'floating cottage' in Thai style , but I just found this discussion of an interesting project being carried out over on the Mekong river in Thailand. There are a number of dwgs, photos, and a couple of videos....enjoy, Brian

Next week, we will begin building a 9m Cat using a teak wood frame and about 5,000 plastic bottles which have been collected in and around the Mekong River in Thailand.

The goal of this charity project is to use the boat to help educate locals about protecting the Mekong River. Once the boat is built it will sail from northern Thailand, through Laos, and back here to Nong Khai, stopping at villages along the way and encouraging them not to throw trash in their river. If successful, the journey will continue down the Mekong until we reach Cambodia.

http://www.cruisersforum.com/forums/...les-43675.html

[MAINSTAY]

Brian
Congratulations. And it looks good, too.
It looks like a frame and skin filled with bottles; like Plastiki did and they made an ocean passage.

I have no hope that whatever comes out of this thread will look half that good.
LMo

[MAINSTAY]

Russ,
Here's the outline of the boat I envision.

1. A rigid structure to hold everything together. Plastic bottle hulls are attached below. A mast is attached above. A deck and shelter set on it. And something to steer with and something to reduce leeway is attached below.

2. Each hull is envisioned as composed of a number of sealed 10mm (4") PVC pipe as long as the hull wrapped in a layer or two of 2-liter bottles. These are tied to each other at intervals and at ends to form a hull. The hull may be covered in non-biodegradable geo textile and sealed with a waterproof membrane. The PVC pipes may be interconnected in one hull and used as a water tank. The pipes in the other hull may be interconnected for separate tanks for fuel, gray water and black water. No accommodations are envisioned in the hulls,

3. The deck may be plywood sheets. But cloth tramps a solution too. Shelter may be a tent or leanto; or it may be a large PVC drain pipe ( 1 or 2m) with a plywood floor raised enough to give a flat surface to sleep on and give storage/bilge below.; or it may be an old airplane cockpit. Whatever is handy.

4. The standing rigging may have an unstayed mast with a tabernacle or such as part of the rigid structure. The flexibility of the hulls makes it unadvisable to attach stays or shrouds directly to them. So the rigid structure would need to extend to the lower end of any stay or shroud used. A junk, lug, or gaff rig with its low center of effort would be a better match for the hull than a wingsail or bermuda rig. Also, the lower CE means lower loads on the rigid structure and on its connections to the hulls. The rigid structure would need to be extended to all points where the running rigging is attached.

5. Steering by rudder creates forces in many directions. Attaching a rudder to a hull may not give adequate support to the rudder and the rigid structure would need to be extended to the transom. If an oar is used for steering, the extension of the rigid structure and its weight are not needed. The oar could help get out of irons. I'm not sure this boat will have enough polar momentum to carry if through the eye. If so, it would then be helpful to mount the anchors and chains at beam ends. Also, the steering oar could be used as a scull in port. If oars, there should be two, with twin oarlocks at the aft of the rigid structure for steering, and two more at the gunnels for rowing.

6. The hulls are presumably too flexible to hold a centerboard or keel. That is the function of the rigid structure. Some braces or such would extend below the deck to support a frame for the center- or dagger-board. If we ever get a deep water version, I'd have another daggerboard and two more support frames, one forward and one aft. In this way, the daggerboards could be wet fore and aft and be raised or lowered to balance the CLR and CE so the boat stays a course without someone constantly on the steering oar.

7. The rigid structure holds everything else together. The shape will be that which best supports everything attached to it. It could be rectangular with the hulls attached under and parallel to the short sides. If the hulls are stiff enough, then maybe the short sides are moved inward so it resembles a Roman numeral 2. If the hulls are too flexible, then maybe the sides can be extended and it looks like a Roman 2, but the other way. It could be triangular, hexagonal, or even like a plus or minus sign. It might be made of old spars, used lumber, or tree trunks. It might be a meter-high truss all around the deck made of PVC pipe, and serve as railing, too.

Does that sound like a wordy retelling of your initial concept?

I think we can develop the details to make this work.
LMo

[brian eiland]

Originally Posted by MAINSTAY

Brian
Congratulations. And it looks good, too.
It looks like a frame and skin filled with bottles; like Plastiki did and they made an ocean passage.

Be aware it was not me who had anything to do with this project. I simply reported it on this forum in a 'quote' from their original posting. Sorry if that was unclear.

I live in Thailand part time, so projects there are of extra interest to me.

Brian

[MAINSTAY]

Sorry, Brian.
But still, thanks for posting it. It is very on topic.
LMo