DRP #4: Breakwaters
December 30, 2008 at 2:36 am #4601
Deep down there are no waves. I’d like to drive some thinking to that area because much of this thread is related to the surface where everything is difficult.
For example, what about a huge horizontal plane made of cheap material (plastic?) about 40m (130 ft) below sea level, keeping the breakwater or the seastead itself in place. A huge amount of mass at surface area could be similar to using the mass of water deep down by just capturing the latter.
A plane made of plastic would oppose vertical movements; adding vertical parts would oppose horizontal movements as well.
Another thing we should think about is to simply divert waves. A ship in a bad storm navigates towards the waves. Similarly, the breakwater could be shaped in a way to divert the waves to the sides (provided the (biggest) waves come from one side and we could turn the whole breakwater into that direction).December 31, 2008 at 5:24 am #4608
Design space: Meaning various sizes and costs of seasteads. We could design seasteads for one person, one family, 20 people, 200 people, 2000 people, etc. Each size may dictate a different design, and will have a different cost. Other aspects of the design space are wave size it can handle, and mobility. So what I’m saying is, we are working on designs of several different sizes.
200-person resort: TSI is a small nonprofit dedicated to advancing the cause of seasteading. We can’t fund or develop a project like this. We are just trying to prove the concept, and then publish all the information in the hope that someone with access to the kind of capital required picks it up and funds a business venture. We do not currently have any such investors.
The patent application is expected to be filed in the next couple weeks, at which point we can publish the basics of the design. What will take a couple months is for the consultants to finish the full write-up.
Prototype: Depends what you mean by 1:1. It will be a small version, in the sense that it will be designed for a small amount of living space so that the structure will be cheap. But not small in the sense that the chairs or toilets will be 1/2 size, like in a scale model. It will be a full, working seastead.December 31, 2008 at 5:58 am #4609
I don’t understand how the horizontal plane helps stop the surface waves, which is the goal. Entraining water is a common technique to add mass, but you still need to stop the waves somehow.
The problem with diverting waves is that ocean waves are waves, and so they diffract around obstacles. A single breakwater segment, rather than a circle, does not create a large rectangular shallow area on the side away from the waves, as you might think. Instead, it creates a small shallow area because the waves diffract around it. This is one reason for doing a full circle.December 31, 2008 at 2:29 pm #4610
The plane is not meant to stop waves, but to provide a steady “anchor” to fix the breakwater (so it doesn’t create waves on the wrong side itself by bobbing). The breakwater would need a lot less mass.
The diverting idea is that you wouldn’t be using a circle but for example a shape like this. If a big wave comes from the right, it’s impact might be smaller. (similar to why a boat should point into the direction of the waves).December 31, 2008 at 9:46 pm #4613
Put a couple new sketch-up images on my floating marina page:December 31, 2008 at 10:15 pm #4615
The breakwater will likely be massive, and unlikely to bob. Even the design I proposed won’t bob very much.
The diverting idea makes sense, that seems like it could be much weaker and use less materials than just putting up big walls. But it requires orienting towards the biggest waves. And rogue waves can come out of directions other than the prevailing sea. My impression is that “no direction is safe”, although I only have rough knowledge about ocean waves.January 14, 2009 at 10:59 pm #4692
Well, we know how we could get around from blimp to blimp…January 22, 2009 at 2:01 am #4711
Just a quick thought..
Water can contain up to 26.4% salt, normal seawater contains about 3.5%. It should be easy to create salt at sea assuming the weather is good enough (for me priority number one anyway :)). We could create a huge pool of it, keeping it together using plastic and afloat using something cheap like polystyrene. Regardless of shape, the bigger the pool the cheaper it is per cubic foot. If rain is kept away, it would get saltier by itself btw.
I haven’t (actually: can’t) do the calculations, but it feels as if a density of something like 1.26 compared to 1.03 makes it 25%harder for the “light weight” waves to make the heavy water move; reducing the waves by 1-(1/1.25)=20% at very low cost.
And of course, extremely salty water is also a lot of fun to swim in.January 22, 2009 at 2:22 am #4712
A breakwater made of water is a lot cheaper than one made of concrete; a breakwater being massive implies that is also expensive (even with concrete being quite cheap). I’m sure that if we could entrain water efficiently we could use it to stop or damp waves a lot cheaper than any other solution.
I guess a rogue wave just needs to be survived, being a nasty situation anyway. There is probably no viable breakwater able to fight a rogue wave. Diverting waves may help reducing everyday movements of the Seastead just to be more comfortable. The shape i drew might be self-directing btw, assuming waves push objects to the position they have the least impact like winds do (but i’m not sure about that).January 23, 2009 at 11:22 am #4722
One thing that can be tried, is to brake the waves horizontally below the waterline. The rationale for this is that periodic lateral efforts do not affect a seastead’s comfort as much as periodic vertical efforts, especially when the seastead has a lot of wet surface. Since the waves’ energy travels in a forward-rolling circle, we can put obstacles to this travel at any point of the circle: instead of opposing the up and down movement, we can oppose the forward and back movement. Instead of entraining water with horizontal plates, let’s entrain water with vertical plates and lay this wavebraker flat at some depth. Think of it as an enhanced version of Patri’s “aikido” breakwater.January 24, 2009 at 1:19 am #4726
This should be somewhat self-explanatory. A number of these are placed in a circle to protect an area of ocean against waves. See Vince´s Tension Circle Marina for details: http://wiki.seasteading.org/index.php/User:Vincecate/Tension_circle_marina
The connection between segments function like a simple door hinge. You float two segments close together. Then connect the hinges in the order: middle, top, bottom. This is in order to line up the bottom hinge without seeing it (no divers required).
The wires that function as the “spokes” of the “wheel” are pre-connected to the segments, one on each side, top and bottom, respectively. The tension from the hub will thus pull the hinges tighter.
The “keel” is an attempt to be able to use one piece moulds in the construction of these things. This way you can just lift them out when they have cured. I am not sure how realistic this is.
The rectangular space inside the breakwater can be used as real estate. Housing, commercial, storage or whatever. The top deck can be used as a walk- or driveway.
The rectangle is 5×3 meters on the outside. Total height excluding glass fence is 6,5m. Length is 20m.March 20, 2009 at 1:41 am #5258
A bit late, but it’s an interesting subject.
The Wikipedia article is nice, but this one is particularly interesting: http://www.seafriends.org.nz/oceano/waves.htm
One of the surprising features of waves is that their height hardly correlates to the depth where you can still feel them. That depth is 0.5 the distance between two waves. To completely avoid waves by submerging, you’d have to be really deep.
-JoepMay 12, 2009 at 11:53 am #5966
Googling for “open ocean breakwater” returned this link to a 1975 paper as the first result.
TFB: A transportable open ocean breakwater
Essoglou, M. Seymour, D. Berkley, J.
Naval Facilities Engineering Command;
This paper appears in: OCEANS
Publication Date: Sep 1975
Volume: 7, On page(s): 723- 725
Current Version Published: 2003-01-06
Abstract The paper describes a unique floating breakwater under joint development by California and the Navy. The transportability of the system makes it applicable for temporary protection of offshore construction projects, as well as for a number of permanent installations where conventional breakwaters are not feasible. The results of the development program are described, including the successful demonstration of a limited fetch breakwater in San Diego Bay. Plans for an ocean scale experiment during the next year are outlined. Recommendations are presented for the commercial development of the system to meet national needs-both commercial and military.
I’m basically just throwing it out to see if it’s already been mentioned, to see whether anyone has reviewed the full paper, etc. Maybe they already have. TBH I haven’t checked this site to see. If it’s already been covered, then pardon the duplication.
(Why an electrical engineering society has a journal on ocean engineering isn’t entirely clear.)May 12, 2009 at 11:43 pm #5976
We have not yet done a literature search on breakwaters, so that is new to me. Let me know if you manage to find a copy of it.June 15, 2009 at 3:54 pm #6531
A seastead is basically surrounded by hostile territory wherever it goes. So reliability of waterbreaker systems is a must. I always like the KISS principle (Keep It Simple Stupid). The less (moving) parts something has, the less that can break down. Constructing huge concrete floating breakwaters has some advantages. It’s a “simple” wall, no moving countermechanics or computerized stabilty or attenuation systems.
Also, it’s completely passive once in place. It will not require energy to stay afloat or break the waves but will make none in the progress as well. This last problem could be resolved by attaching the relevant tehcnology to the breakwater, but the breakwater itself should not be reliant on this technology being in place.
Of course the downside is the initial cost, and although a modular system could be designed to be able to expand the breakwater enclosure to gat a viable economy of scale all this will be going against the semi-mobile nature of the seasteads. Although the tension circle design would allow for more mobility, the size of the breakwater would be limited (although the rise of carbon nano tube tethers could change this).
I’m not a marine engineer or architect so I don’t have nothing new to add on breakwater design (there are people out there who do nothing but breakwater design for yearson end).
I did find this interresting article, it seems a bit impractical to build but at least the idea behind seems promising:
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