How to build a floating island from mostly Hefty Garbage sacks.


    There have been objections to this method by persons who haven't tried it. However, it has been successful in ocean salvage work. The exterior of the island, where damage might occur is protected. The 4 mil. thickness of the Hefty Sacks, although thin, should not be effected, if they are kept out of sunlight, such as under an island. Like recycled bottles, if one or more springs a leak the others still support the island. Which buys time for repairs. They are very inexpensive and easy to replace. They can fit unusual shapes, and voids under an island, and they are easily replaced. They do require some underwater work including installation. They are fast, and make quick temporary flotation when needed.

Hefty Garbage sacks have several advantages to this method:

  1. Theyre each cheap! You can easily buy lots of them. Big Glad bags work too.

  2. Being made of Polyethylene plastic, they should last a along time underwater.

  3. Dont buy the biodegradable kind. You dont want them to degrade.

  4. They are strong, for their weight. You can get the ones made for leaves.

  5. A 35 gallon sack full of air, should hold up 290 pounds (131 kg) in water. Thats a lot of island.

  6. You can take an air-hose underwater with you, and blow them up where they go, so you wont have to fight them into place.

  7. Concerning your air hose:
    • Dont electrocute yourself! By using electricity near water. My ebook, Saving the Planet, while making a profit shows an easy-to-build vertical axis windmill called a floppy mill. (You can also use it later for other things.) Hook this type, (which works with wind from any direction.) to an air-pump made for spray paint. It has a moving diaphragm without harmful petroleum oil.
    • If you need to breath this air, you can.
    • If you cant get a pump without petroleum oil, clean the one you can get real well, then fill with vegetable oil, that wont hurt you.
    • Or build an old fashioned air-bellows.

  8. The sacks should be placed with the opening on the bottom, twisted and tied tightly, so, hopefully, the air will stay in.

  9. You hold them in place with fishnet-like macram tied with plastic string (so it wont rot) and can be connected easily to the bottom bottles of the deck. Or use the method shown in my article on it.

  10. Tie a knot in the middle of each string, and bury it in the NFRC so it holds on tight.

  11. In the middle of your island, they protect each other, and even push the water out of the way to hold your island up.

  12. But on the edges of the island they may need protection.

  13. During construction, the netting will work, but you may have to replace some when a boat, floating tree stump, or whatever runs into them.

  14. Granted they are easy to replace, but who wants to?

  15. First, build a floating deck, and protection sides for your island.

  16. Hex shape makes a strong island, thats hard to bend. But if you wish wave action to telegraph through, use squares.

  17. Use natural fiber (like Ponderosa Pine needles. I used strips of coconut leaves in the tropics, or other strong broad-leafed fibrous plant leaves,) dipped on both sides in Portland Cement, mixed without sand or gravel, using just enough water to make it moist. Extra water makes it not only thin, but weak too. Cover the whole project with plastic sheeting until one week has ellapsed so it will cure properly.

  18. Portland Cement (when mixed right) will withstand even saltwater. (The Navy uses it to coat piers and docks.) Cover both sides of the fiber material, (even strips cut from old cotton clothes,) getting both sides completely covered. Lay it like paper mach with strips crossing each other so you get tensile strength in both directions, without gaps. Make sure the fibers overlap each other, at least 2 or 3 inches.

  19. Lay a minimum of two layers 90 to each other, then recycled soda bottles, laid on their sides, tight together for the floating deck. They can be ordinary 20 ounce (591 ml) sized soda bottles, even different sized ones. They just form a floating deck, you add major buoyancy later.

  20. You actually build it in sections (with a rot-proof, even plastic means, for tying them together later,) placed up-side-down on a flat surface (like a driveway, parking lot or what-have-you) on a sheet of polyethylene plastic, so it doesnt stick your project to the ground. It makes a nice shiny surface too. Or put a layer of sand to make a sandy finish.

  21. The section ties can be of plastic rope or string looped with just the loops sticking out, but the rest having a knot buried in the cement, put them maybe, 8 inches (20 cm) apart, so you can tie the finished pieces together in the water. Make them at least as big as a piece of plywood, but not so big that 2 people cant pick one up.

  22. First lay out the crossed strips, then while its still wet (before 3 hours) place on the recycled soda bottles, covering the whole surface with them on their sides. You may need to add some strips over the bottles, just enough to hold them permanently onto the fiber cement below. Or bury a plastic string for each one, with a buried knot in the middle, so you can tie them on later. You only have 3 hours of work time, because the Portland Cement will start to harden and cure.

  23. Remember it takes at least a week for the cement to get hard and cure completely, so dont try to move them until then.

  24. For the island sides, remember that one side has to sink and the other side float, to provide a vertical wall to protect your Hefty Garbage sacks. Build it so. Or use Brian's automobile tire segments for your edges.

  25. You can launch, with the bottles down, for the deck, plus its island-protecting walls, but you probably cant walk on it in the water yet.

  26. Take the plastic string fishnets you made, (while waiting for the cement to cure) each the size of a blown up Hefty Garbage sack, and go under the island and fasten each one to the bottles of the floating deck above.

  27. Put a Hefty Garbage sack in each fishnet and blow it mostly up with your air hose. When almost full, tie the bottom of the opening tightly to keep the air in.

  28. Put as many as you can under the island. Leave no space for damage, or wasted buoyancy space.

  29. When the whole island is buoyed, and filled with sacks, you can go topside and use a pump to suck sand off the bottom of the harbor (or wherever you build it) to make a nice beach to relax on, and have a beer. I told you that windmill would come in handy later.

  30. Remember, if youre going to use this method for deeper water, as in salvage, you can only fill the bags about half full, because the air will expand and break the sacks before they reach the surface.

  31. In fact, do not fill the ones for your island 100%, because it strains them, leave room for some expansion as the environment changes.

  32. As you add weight top side, like a geodesic dome, you may need to add more sacks for flotation. Just tie their fishnets to the ones just above, so the waves or current wont float your bags of air away.

  33. Now there exists a circumstance where there is little wave action. In that case, the fishnets may not be needed. So just slip a plastic string or rope through the plastic loops, on each sack, after the sacks are tied, so they dont get away. And, also tie them on top to the bottles, but try to keep the sack openings down. You might have to tie a rock there to keep them weighted down.

  34. Now dont use bowties! Tie with square knots, so the tie is permanent and the air stays in, even twist the sack and wrap it with the plastic ties real tight.

  35. Id love to hear how it goes, so write me, and with any questions I can answer. Please send lots of pictures, close-ups too.


    Update 2-24-12