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Matthew Murphy

(1)

Howdy Just thought that I would put my 2 cents in. The design for the low-tech floating island has major drawbacks. The use of plastic bottles, which photodegrade, is not even remotely environmentally friendly. Add to this the problem of the island eventually falling apart because of lack of structural integrity and we arrive at a problem, not a solution. The bottles could be housed in a cement ' donut ', thus sealing them from interaction with the water, air and sunlight, thus delaying the problem of eventual degradation but, inevitably, there will still be an environmental negative in the use of such material. I would suggest a rethink on promoting this as a project.

Kris De Decker

(2)

Matthew, you are right that plastic bottles eventually photodegrade, but as far as I understand, this process takes at least 100 years.

You don't put these islands in some far away lake and forget about them. This is a method to clean up urban bodies of water in your own surroundings, which means that you can monitor them.

It does not take 100 years to do the cleaning job, so after some years you take them out of the water again. If they get in a bad shape before the job is done, you take them out and install new ones.

I. M. Moderate

(3)

Photo-degrade is highly variable with composition of the plastic and its color doping. Plus the 100 years type figures are for total dissolution into the environment and not structural failure versus sinking (try 3-5 years if you are an optimist). I suggest you go look at some plastics in the wild and note their condition versus exposure to sun and apparent age.

On the other hand you cannot count use of materials already present as additional pollution.

Yet I suspect that without more work than profitable the downs still outweigh the ups. Maintenance on such ad hoc structures would be horrible or use add-ons that would quickly grow the structure past reasonable size. Plus you are creating swamp conditions for pest insects like mosquitoes. Not bad if the area is already swampland but not good elsewhere.

In the end it would be better to melt and otherwise recycle the floating trash into usable structural elements of higher reliability and durability.

I. M. Moderate

(4)

Since the cans and bottles seldom come with caps, especially tight caps, I can see you are already so labor intensive with melting and testing seals -- that this must be intended more of a case of "practical art" commentary than truly practical solution.

People are always ready to put far more labor into art and political commentary projects than into a project that is far more efficient but purely mundane. I prefer the rare case where these folk help engineers make mundane stuff blend into the environment or appear beautiful.

And I have to agree with the first guy that the first incarnation of this sort of project probably sank or broken apart within few weeks. However, each incarnation would probably last longer as the leadership relearned practical engineering lessons the hard way.

One of those engineering lessons would be that humans in boats are going to mess with this floating island. The most innocent probably being fisherman after the fish gather underneath the float.

Martin Ellis

(5)

Could I suggest that a raft be made from some type of bundled reed? similar to those used in Iraq. Although perhaps some further boyancy cuold be afforded with coating the reeds with a ersin from pine trees or the like?

We see reed mats and rolls used to filter silt from stormwater or surface water runs... so assume that works.

But I would rather see one big polyetheleen drum used as a primary float than a bunch of plastic bottles. Only becasue it is only one piece of litter that can be removed later.. and tethered.

Although what you use for your teathers and hold lines is probably just as risky?

I have seen a system used at Auckland Sewer treatmetn ponds.. they use a geogrid product.

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