New feasibility study: Semi-submersible, “mini-modular” plaftform

Seasteading demands a nimble balance of practical present technology and untested innovation. Our latest engineering study, part of our Floating City Project, attempts to strike this balance by examining the feasibility of using a semi-submersible as the platform for the first open-ocean community. “Semi-subs” are state-of-the-art existing technology for deepwater drilling and worker accommodation – their comfort and stability is unmatched, but is not without cost. Our director of engineering George Petrie set out to design a 300 by 300 foot steel hull and deck, and delivered the blueprints to shipyards for estimates this past Spring. In May 2013, we received a bid from a U.S. Shipyard providing initial results for feasibility.

We have broken out the most important cost figures on a new Semi-Submersible Feasibility Study page. The hull and deck structure was estimated at $115,492,000, just over half of the total estimated Capital Expense (including residential units, towing to the Caribbean, mooring, etc.), of $225,744,251. This works out to slightly less than $978 per square foot of interior space. Maintenance, or Operating Expense, was estimated at just under $9 million annually for the roughly 360 person platform.

The five floors of residential and commercial units atop the deck economize on surface area – cities have always grown vertically, adding layers of complexity and creativity through density. We have also created a new page for the design, layout, and operating mechanism for a “mini-modular” experiment, created by Naval Architect Lina Suarez under the guidance of George Petrie. Suarez’s design enables the ability to easily enter or exit the seastead (i.e., voting with your house), which in turn amplifies the competitive pressures needed to spur governmental innovation. True modularity would involve linking full semi-subs, ships or other floating platforms together, such that they could disband or rearrange with ease. Nonetheless, modularity at the level of apartments on a single platform provides residents additional freedom of choice, and creates a novel experiment in real estate development.



This design is not the only configuration we are investigating as part of the Floating City Project We are also partnering with Dutch aquatic urban design firm, DeltaSync, to engineer a novel architectural seastead design, which will be released in the Fall of 2013.

If you believe you can help The Seasteading Institute actualize these plans, or provide us with a lower bid on any of the semi-submersible components, we would love to hear from you. Email us at .



1 thought on “New feasibility study: Semi-submersible, “mini-modular” plaftform”

  1. You should consider using ElectroAccretion/BioRock tech to grow components onsite, instead of having to tow them from elsewhere. My group has different options to offer, and we are also looking into using cellulose nanocrystals, and basalt, in a geopolymer composite, input to the 3D mega-printer, D-Shape, to produce components for pre-fab and modular structures off-shore.

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