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    Profile photo of crasch

    A few random points:

    Pictures of a cement submarine:


    One reason that ferrocement boats have not caught on, from what I’ve read, is due to the difficulty of evaluating the integrity of the hulls, which makes it difficult to get insurance.

    FYI, new carbon fiber rebar and reinforcement meshes are becoming available.


    Carbon fiber/concrete structures should be impervious indefinitely to salt water corrosion, without much maintenance, unlike steel or fiberglass.

    Keim mineral paint jobs have endured for over 100 years, and have been adapted for marine use:


    Profile photo of crasch

    Added this to the prize wiki.

    Profile photo of crasch

    Why should a single person be able to build a seastead? You never see someone build a house just by himself. There are always a few more people involved.

    Since I see this as a “low cost” design prize, requiring that it be buildable by a single person with a pickup ensures that the labor costs will be lower.

    Many people build houses by themselves. My parents built two. (Of course, they bought the component parts (lumber, concrete) from external suppliers, but they put them together themselves.)

    Note that it must be buildable by a single person, not that it must be actually be built by a single person. I’m open to allowing teams of any size build them, provided that, in principle, it could be built by a 1-2 man team.

    Profile photo of crasch

    To me, what distinguishes an (ideal) seastead from a boat:

    – sea-bound — stays out at sea indefinitely (no or rare docking)
    – longevity — 100+ year lifespan
    – semi-stationary — stays within roughly the same region of the sea
    – spacious — lots of space per passenger, relative to boats
    – wave-resistant — little wave motion under normal conditions; can survive rogue waves
    – higher passenger duty cycle — most passengers expect to live on seasteads fulltime
    – multi-purpose — designed to house all of the same businesses as exist on land (dentist office, grocery stores, etc.)
    – modular — can combine with each other to form larger structures

    Given those design goals, some of the criteria we might consider for a prize:

    * Cost – Can you build the seastead under $X dollars
    * Station keeping — Can the seastead inside a circle of x-radius for y period of time?
    * Ease of construction — Can a single person with a pickup struck and readily available tools build it?
    * Comfort — Does the seastead bob no more than X when waves are height Y?
    * Safety — Can the seastead tolerate waves of height X without excessive damage?
    * Modularity — Can the seastead be easily combined with other seasteads to form a larger structure? Does it tile?
    * Spaciousness — Does the seastead provide at least X sq feet of living space?

    Here’s one set of criteria we might set for a prize:

    Must cost no more than $50,000.00 to build.
    Must not require any tools that cannot be bought at Home Depot, nor require more than a pickup truck to transport.
    Must provide at least 6000 square feet of living space, consisting of at least three tileable modules that are connected to each other for the duration of the contest (tileable means that you could expand the structure in any direction by adding more modules)
    Each module must be of equal size (+-5%), and capable of long term flotation on its own.
    Each module must have positive buoyancy and be capable of floating even if fully flooded.
    Must not move outside a 1 mile radius during the year at sea. Station keeping must not require active human intervention.
    You must find someone __who is not the builder/designer__ to live aboard full-time for at least one year.
    After a year at sea, must sell at auction on Ebay for at least $50,000 to someone unrelated to you.

    This would require a big prize, obviously. We could also offer smaller prizes for models that meet the criteria at a smaller scale.

    [Edit, 2008-10-29: I thought of a couple more.]

    Must be located at least 24 miles from shore during the year long stay.
    Must make all it’s own water
    Must be capable of moving under its own power at least 5 mph for 100 miles without refueling

    Perhaps we should also think about explicitly what are _not_design criteria:

    – size – no max on size
    – weight – doesn’t matter how much it weighs (although individual parts must be transportable by pickup)
    – speed – does have to move more than 5 mph
    – build-speed – doesn’t matter how long it takes to build
    – does not have to be energy or food self-sufficient; food and fuel re-supplies are allowed. (Although perhaps we should make this a criteria for the prize, even though seasteads would not need to be self-sufficient).

    Profile photo of crasch

    Those course sound quite interesting. Thanks for the pointer!

    Profile photo of crasch

    Hi Vince,

    Perhaps you could create the model out of a nylon fishing mesh/cement composite over a male sand mold?

    First, make a large diameter half-sphere out of sand:

    1. Use a a string attached to a stake to draw a circle in the sand.

    2. Lay down a large piece of cardboard, large enough to completely cover half the circle. Glue several layers together if necessary to make the carboard rigid.

    3. Cut out half the circle from the cardboard, leaving the half-circle as a negative space in the remaining cardboard.

    4. Pile the sand to the desired height, and shape it to a rough half sphere. Rotate the card board form up and over the pile, smoothing the sand into a uniform sphere. Fill any gaps as necessary.

    5. Once you have a satisfactory male mold, overlay it with a layer of nylon cement, as discribed by Bill Birdsall (1)

    6. Once the shell hardens, you should still be able to cut out hatches, windows, etc.

    7. Create a second shell the same way.

    8. You could join the two shells by leaving a layer of mesh exposed extending beyond the edge of one of the shell. Once the shells have hardened, you could put the shell with the lip of mesh on top of the other, and then cement the lip to the bottom.

    1. http://www.angelfire.com/in2/manythings/TEXT/NYLON-CEMENT.htm

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