Research Update: TSI Engineering Assessment Report (part 1) released
Mon, 03/01/2010 - 18:41 — nthmost
Thanks to Eelco Hoogendoorn and a host of valuable community support, our first offical Engineering report is now available for general parusal. You can pick it up from our new (and still in-progress) Research page, or download the PDF directly here.
From the Preface:
This document is a high-level analysis of the engineering challenges involved in homesteading the high seas. The aim is not to provide a detailed design of a specific seastead, but rather to find answers to general questions, such as the cost per unit area of functional real estate.
Note: This is a first draft of this report. It is being publicly released for community feedback. Due to still being in a state of considerable flux and expected changes due to feedback, polishing is not yet high on the agenda. Please send any feedback you might have regarding content to eng@seasteading.org.
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The PDF link doesn't appear to be functional.
fixed PDF link
Sorry about that -- the link is fixed now!
I mostly agree with the
I mostly agree with the sections on mobility and station-keeping.
I'd like to see a calculation of power requirements for a used cruise- or container ship. Clubstead does not seem like a good candidate for dynamic positioning.
Knowing the propulsive power and top speed of a ship one should be able to easily calculate how much power would be needed for a loitering speed of a couple of knots, with optimized propellers.
http://commercial.apolloduck.com/display.phtml?aid=129684
The drag force equation in your paper seems to me like it depends on the velocity squared.
If v=14.6 knots and P=9480 kW, then a v of 2 knots would require a P of 178 kW.
Is this correct?
suitiablilty to purpose and appeal
The large prestressed concrete LPG vessel is fascinating. Cost is not mentioned, but we can estimate $9 million+ for the concrete alone based on the 12k cubic yards of concrete used and Eelco's estimate of $1000 per cubic meter of constructed concrete. I hope everyone reads the report about it. Similar constuction techniques could probably be used to build seasteads. Interestingly the technology is more commonly used to build bridges. Concrete Technology Corporation in Tacoma, Washington was the builder:
http://www.concretetech.com/
The engineers were ABAM:
http://www.abam.com/
Who have built a number of innovative floating concrete structures:
http://www.abam.com/portfolio/pmw/innovative/index.cfm?id=88
Note that it was built mainly to the 140m wavelength of the semi-protected waters it is buoyed in. For the open ocean a structure would need to be at least 300m long to deal with the longer wavelengths present. Therefore, while incrementalism and modularity of single family units is desirable, it may not actually be practical on the ocean. It may be possible to have small housing uints if a large structure existed onto which individual homes or apartments could be placed, but it frankly seems impossible to create a (rigid) 300m structure from smaller modules. It's a great idea, but probably not doable. At best, it may be necessary for someone to own the "land", even if it's the deck of a ship or semi-submersible to place the houses onto.
Lots of folks are finding ways to make housing from shipping containers. Perhaps one way to start would be to put container-based homes onto a container ship, if we must have modularity. Both containers and container ships are plentiful. I believe there's currently a massive surplus of them due to building cycles started during the boom and lack of business now. Personally I would like a (converted) cruise ship better. A far less expensive, better business-modelled Residensea would be fine.
Your proposals for a flexible structure are certainly interesting and very creative, but personally not too appealing. I'm not sure how comfortable people would be with "the land moving". A large cruise ship is probably more comfortable, familiar, and appealing.
Frankly until someone comes up with something better, it's hard to beat a 300m ship on the open ocean. (I think a 300m multi-spar structure like a larger Clubstead or Seadrome could be better than a ship for stability, durablity, etc.)
I'd like to see a
I'd like to see a calculation of power requirements for a used cruise- or container ship.
It isnt included, since it is expected to be so much lower. Station keeping, or moving at a knot or two, shouldnt be a problem for a ship.
Clubstead does not seem like a good candidate for dynamic positioning.
The drag force equation in your paper seems to me like it depends on the velocity squared.
If v=14.6 knots and P=9480 kW, then a v of 2 knots would require a P of 178 kW.
Is this correct?
The large prestressed
The large prestressed concrete LPG vessel is fascinating. Cost is not mentioned, but we can estimate $9 million+ for the concrete alone based on the 12k cubic yards of concrete used and Eelco's estimate of $1000 per cubic meter of constructed concrete. I hope everyone reads the report about it. Similar constuction techniques could probably be used to build seasteads. Interestingly the technology is more commonly used to build bridges. Concrete Technology Corporation in Tacoma, Washington was the builder:
Note that it was built mainly to the 140m wavelength of the semi-protected waters it is buoyed in. For the open ocean a structure would need to be at least 300m long to deal with the longer wavelengths present. Therefore, while incrementalism and modularity of single family units is desirable, it may not actually be practical on the ocean. It may be possible to have small housing uints if a large structure existed onto which individual homes or apartments could be placed, but it frankly seems impossible to create a (rigid) 300m structure from smaller modules. It's a great idea, but probably not doable.
I disagree; from what I can tell, based on an admittedly crude analysis, linking a set of concrete modules into a structure long enough for open ocean operation seems plausible. Still, these modules wouldnt quite be 'single family', but more like 40x40x50m blocks of concrete, but you could start with one in protected waters near shore, at a budget I am confident TSI could get funding behind, and provide a plausible path to eventual international water operation.
Anyway, more on this in part 2!
A cubic relationship is what
A cubic relationship is what I calculated with in the above example. Are you saying it would be better, ie even less than 178 kW required to maintain 2 knots? Assume that we add electric thrusters with propellers optimized for this speed (2kt). I understand the regular props will likely be too inefficient going this slow.
I am trying to determine whether it would make economic sense to power the dynamic positioning of a ship with something like PV panels.
Umm no wait strike that. I used a squared relationship. Cubic you say... interesting...
Miguel, who also spoke at
Miguel, who also spoke at last TSI conference, has done his thesis project on solar powered fishing vessels. He seemed enthusiastic about it.
Backup power would still be required though, as the dynamic positioning would presumably also be what guarantees individual seasteads dont bump into eachother. But it could help offset fuel costs, if it proves competitive with other means of energy generation. That said, taking into account that there isnt anything like cheap horizontal surfaces on a seastead, I doubt it.
Wingsail for positioning
Has anyone looked into using a (wing)sail for stationkeeping? In principle you can sail to any compass point except straight into the wind. (BTW the wingsail seems to be superior to a cloth sail. Ask Larry Elison...) I think Vince looked at kites for transit, but it too may be useable for stationkeeping, with some differences. As long as the current and wind forces can be made to balance out, it ought to be doable and save a huge amount of resources compared to engines or generators. One could also use windmills to at least partially energize stationkeeping, assuming more wind than current or drag. Any could be backed up by a diesel generator or run as hybrids.
Very interesting report
Very interesting report Eelco! And thank you very much for including me in the Acknowledgements.
* Barges:I had deleted the barge option from the very begining as I thought that Seasteading was not possible in the EEZ. But I can see that you are considering it. This could lower the costs a lot. See for example:
http://www.dredgebrokers.com/Barges_Work/90214-BW/Barge.html
And complies with small scale and modularity:
Price for Barge: Standard Accommodations 32 berths: EUR € 3,950,000
Price for Barge: Optional accommodations 106 berths total and recreational unit: EUR € 5,950,000
But what about mooring a Seasted in the EEZ? It could be considered an Artificial Island, and as a consequence, not allowed in that waters...Perhaps with DP it could not considered it: you have the barge sailing at low speed from one place to another. Something very important as you say in your report: Inside or outside EEZ is the key!
* Solar powered vesels: one example here:
http://www.inhabitat.com/2009/07/06/auriga-leader-cargo-ship-gets-power-from-solar-panels/
For a cargo vessel is not suitable, but for a Seastead it could be a good real option as you do no need so much power!!