Breakwater Design


#267

Have you ever eaten seaweed? A lot of it? To me it tastes awful. I lived in Japan during college, and ate seaweed at breakfast and dinner every day for a considerable period. In Japan it seems to be used more for flavor and nutrients than a staple. Seaweed is high in vitamins and minerals. It is not very filling.

I actually think Sargasso itself may be edible and sustainable. It does not need a bottom like Kelp, and can easily be held by loose floating nets. (Sargassum, or here in the us Gulfweed).

I’d like seaweed better if it tasted like steak. So as long as we are dreaming, how about having a seastead surrounded by acres of steak-flavored Sargasso?


(Larry G) #268

Exactly. It’s fine as an ingredient in soup. It’s not a life worth living to eat nothing but seaweed, unless you’re just trying to survive until someone rescues you. There are a lot of ways to get vitamins that don’t taste very good. Sprouting land grains and seeds, spirulina cultivation in fresh water…

Most seaweed is edible, if not very tasty. I believe giant kelp is only viable in colder waters.


#269

Seaweed could be used 2 ways, to produce fuel… Biodiesel and biogas. Hell, could even use some in a gasifier, as engine fuel, and to produce the potash to make the biodiesel.

Sargasso Sea Biodiesel… There’s you another business model, Larry @thebastidge


(Chad Elwartowski) #270

As we begin to think about living on the sea we need to figure out how we can use the things that are available for every day items we usually get from land. I wasn’t talking about eating the kelp. When I think about bamboo I don’t think about the stuff I eat at the chinese restaurant. I think about the many other uses of bamboo. Just like with kelp.

From the link:

Giant kelp is harvested as a source of algin, an emulsifying and binding agent used in the production of many foods and cosmetics, like ice cream, toothpaste and cereals.

Whatever seastead gets going, its success will be enhanced if there is a useful product to export.

This link references some studies that show that in kelp forests the current speed is slower and the wave height is smaller. However it states that too much surge and storms tend to pull the kelp from their footings. So it would not be useful in harsh environments but might be useful in calmer waters.

A combination of several approaches may be the solution.


(Matias Volco) #271

alage is already valuable needed commodity for the food industry; like gum arabic. connected world; differentiation of labor instead of bogus self sufficiency: like the gum acacia of the sahel which provides som bit of shade and nothing else on a local individual level, but on which large global food processing relies on putting the sahel on the economic map


good point, mentioned in post #15 and continued discussion:

floating breakwaters do not work as long as the elements are not signifficantly bigger than the wavelength (2-3 times) a oceanic surface floating breakwater needs to have 400m to start to be effective
. On the other hand even small particles like kelp fields and Mangrove roots DO have an accumulative wave dampening effect.

Nature’s aproach : Wave dampening by - submerged reefs, mangrove roots, kelp fields, sand beach, ice field, gradual dampening, turbulence (sucking gradually energy out of the wave) instead of a frontal crash against a massive seawall …

How do we reconcille these scales and to what purpose? Wicks and generators could create a kelp like forest of seacrete (which can be harvested as aggregate or gravel)

Many ramforms or other volumes of different sizes and stages and uses could together mimick an natural resilient coastline.

Cliff coastlines are perillous and unstable compared to all other gradual dampening naturally occurring coastlines.


(Wilfried Ellmer) #272

consider: seasteading is not about eating sealgea but transforming what we have now into what we envision tomorrow (ref.638) who envisons tomorrow sitting on an isolated thing floating in the ocean eating algea ? | Kelp is certainly a interesting topic in the context of LNG intergration techology | liquid fuel from algea pyrolysis |


Back to breakwater design | @Matias - mimmick natural resilience of a coastline definitly is a strong point

• gradual dampening
• underwater reef

…for phase 3


submerged objects ( here fish cages on tension anchor ) can work wave dampening like a coral reef… (ref 965 ) or a kelp field …


Large underwater objects like a underwater tunnel leading to phase3 seastead can double as reef style - breakwater…


context: | Ocean Sphere | oceanic business alliance | oceanic real estate |



(Matias Volco) #273

Thanks @ellmer for explaining the role of diverse underwater objects serving multiple functions.


Can this distributed approach permit getting to phase 3 in a gradual manner without central planning and monolithic upfront costs?


#274

To clarify (for myself) what is being debated -

  • (#1) the Ramform shape (regardless of the name) is intended to refract the surface wave’s energy away from the floating city. It is not primarily intended to actually absorb the surface wave’s energy. Correct?

  • (#2) the Ramform must be several multiples of potential wavelength in hortizontal length (bow to stern) to be effective. Correct?

  • (#3) the surface waves’ direction can only, at best, be generalized … so the Ramform’s refractive surface must either be movable (to point directly into the oncoming surface waves) or multiple Ramforms must be used to account for incoming surface waves from many directions. Correct?

  • (#4) the Ramform’s impact with the surface wave will transfer some amount of energy from the surface wave onto the Ramform, causing the Ramform to move in (geocoordinate) position. However, if the Ramform funtions as intended, the Floating City will receive substantially less energy from the surface wave, causing the Ramform to move toward the Floating City. Therefore, either a mechanical connection between the two will be necessary or generated energy will be required to maintain separation between the Ramform and the Floating City. Correct?


#275

The true, patented Ramform actually does not have to be any particular size in relation to the wavelength, because of fluid dynamics (think aerodynamics for things in a thicker fluid medium) The shape of the hull does much the same thing as a sternwheeler hull, in that it parts the waves and smooths the flow, ,making for a smooth flow behind the vessel. In sternwheelers, that reduced turbulence translates into better power transmission from the wheel. In hydro-geology, it translates into silence for the microphones of the streamers.

The opposite effect, creating a smooth surface flow, has been demonstrated using structures on the floor, that cause the wave energy to be redistributed primarily in the middle layers of the water, just like natural areas that are almost always calm.


(Wilfried Ellmer) #276

(# 1) yes - in general a bow does split the wave and minimizes the impact forces check on the concepts of “turn into the wind - wave direction” and “get broadsided” to get the idea of why the “how you take a wave is important” …in impact and damage control…
(# 2) no - a ship can ride over a wave without “cancelling or breaking” it nor being “impacted by it” and still have a “privileged calm water area” at the stern area…
(# 3) no | check - turrett mooring | it allows to point the bow in the wave direction always, automaticly and without exception…a ship at anchor give you the correct general image.
(#4) …not sure what you mean …




Wave breaking as a concept only comes in for structures the size of | Monaco Breakwater | Oostershelde | and Mullberry | being Mullberry still too small as it was broadsided and damaged in practice… | context: phases of a seastead


anything smaller than 500 m needs to resort to a bow as wave defense to be feasible… what kind of bow check prelude



(Matias Volco) #277

In the first video above you can see a small floating harbor and sailboats moored to it exactly as they would be moored in a marina, with lines and bumpers. Houseboats can be moored the same way.
As a ramform project grows in lenght so it can accomodate a larger moonpool area, more rigid or flexible connections can be combined.


(Chris) #278

What if it tasted like bacon?


(Gavin Brown) #279

I can see that this topic is about break waters but surely our seastead would have built in wave power generators? I would have Salters duck style generators approximately 5-10 meters from main structure with added horizontal piston style rams so capable of capturing 90% of up, down, and horizontal power from the waves. An enclosed breakwater encircling the whole Seastead does have its advantages of creating a safe haven for other ships but would be a massive additional cost.


#280

In varying types of realistic conditions, the efficiency of the duck varies wildly and often drops to around 50%, as ducks are more often used in rough weather in order to convert enough wave power. Conversely, ducks are not useful in calm weather, as the waves would not have enough energy for there to be any efficiency in converting it.

Ocean energies: environmental, economic, and technological aspects of alternative power sources. Elsevier. pp. 141–142. ISBN 978-0-444-88248-6.


#281

@JL_Frusha - the bow displaces the mass of water sideways when cresting a wave, gravity causing the boat (or Ramform) to plow through the crest rather than floating over it.

But that effect (displacement … caused by gravity) is different from the refraction of surface wave energy, in that displaced water fills the void behind the boat as it moves forward and refracted energy does not.

Surface wave energy is refracted at an angle, and that energy wave then continues in that new direction.

So the Ramform uses gravity to displace water and position the Ramform’s bow below the water surface … and that below-surface position consequently allows the Ramform’s bow to refract wave energy.

To be beneficial for a Floating City, the energy of the surface wave must be refracted by the Ramform away from the city platforms (or dissipated via energy transfer … e.g., using turbines to generate electricity).

A tethered Ramform rotates around the tether, refracting surface wave energy away from the energy shadow (the area behind the Ramform’s stern).

What is the plan for continuously moving the Floating City, so that it remains in that energy shadow?


#282

@Matias - so the Floating City requires a physical connection to the Ramform, and the Ramform must be tethered to the ocean floor?


#283

@ellmer - (#2) - if the Ramform is smaller than the wavelength, then the Ramform’s gravity merely displaces water at the point in the wave crest where the boat’s weight exceeds the wave energy at that point in the crest.

And the Ramform would oscillate (bow-to-stern) around the lateral axis running through the Ramform’s center of gravity as the wave crest moves under the Ramform.

Consequently, the Ramform’s bow (and stern) would rise over the wave’s crest and fall into the wave’s trough … bobbing up and down with each wave.

Only by simultaneously cresting two waves (at a minimum, assuming equal distribution of the Ramform’s weight fore to aft) would that oscillation start to become negated.

And the Ramform’s bow cannot refract wave energy unless it is below the waterline.

So a Ramform’s length (bow to stern) would need to be (at a minimum) several multiples of the most probable wavelengths, or it would not be effective at refracting surface wave energy.

Correct?


#284

(#4) - was answered mostly by the response about tethering.

In contrast to a breakwater - which both retracts/absorbs wave energy and water mass - the Ramform design only refracts surface wave energy away from the Floating City. Displacement by the Ramform doesn’t effect the Floating City.

But, in that refraction, the Ramform’s bow would absorb some energy … causing the Ramform to be pushed to some degree (depending on the angle of the bow, relative to the direction of the wave energy) away from the oncoming wave energy.

Lacking any of the (bow refracted) wave energy, the Floating City would not be similarly “pushed”.

Some mechanism would, therefore, be necessary to keep the Ramform and the Floating City in relative proximity to each other.

Tethering the Ramform and physically connecting the Floating City to the Ramform would address that problem of energy differences.

Thanks for info.


(Robert Campbell) #285

What about seaweed? The sargasso sea acts as a breakwater. So mass - when light individual objects distributed over a broad area - can act to dampen waves.

This is good out of the box thinking, but I’d take it a step further than you did.

Why not design a floating city around the very idea of seaweed aquaculture and plastics recycling, and site it in the middle of an oceanic gyre? You could build a floating kelp raft network a mile across, and put your habitable area in the middle of it. The kelp would effectively act as a mile wide series drogue.

That also gives you another element nobody’s talking about, at least in this thread anyway … sustainable economics. You have an export crop baked into the concept.

edit:

I see I should have read further down.

Crapping on the seaweed farm idea is just as dumb as crapping on the idea of a corn farm because you don’t like corn. You grow corn and sell it and buy whatever you need. That’s how economies work. Without a resource to sell, your entire floating city is just going to be a tourist destination, nothing more.

Instead of looking for a place shallow enough to grow kelp, just sink some long concrete beams off of some floats and grow the kelp on that. Build that into a subsurface hex grid network on pivots, with floats at each of the vertexes of the hex grid, and cultivate kelp on each of the beams. The whole thing undulates in the water, deadens any wave or swell action, and you tie your central living space into the grid. If you site it in the middle of a gyre, it pretty much stays put in the same region we’re collecting plastics trash now, without the need for an anchor - or at least a severe one - because there’s nothing nearby to bump into. If it gets moved by a storm, move it back when the storm is done with some light anchor lines that you pay out during the storm, or with propulsion.

Even if you don’t use all the kelp for aquaculture, it still gives you the breakwater.

And you can use algae as shrimp feed. (as well as some of your sanitary waste) Everybody likes shrimp.

Throw in a plastics recycling operation in the central habitated area to create hydrocarbon fuels for use by the city, while also cleaning the ocean.

That’s the idea. It has a lot of the problems tied up in one neat little bow.

You could fuel the whole city off of methane and sell ethanol to passing boats.

http://www.biomassmagazine.com/articles/2166/british-report-use-kelp-to-produce-energy/


#286

The hull of the Ramform is slanted upward, aft of midship, to the waterline, at the stern, to create the smooth flow, aft of the vessel. As someone that is not a marine architect. I have been in contact with many people, in my study of the Ramform vessels, especially with various departments at PGS, and Mauro Scully, a Marine Architect on the Wally Hermes Yacht prospective designs. I know about as much about the Ramform as anyone that isn’t in direct contact with Roar Ramde, and a Marine Architect can learn, w/o building one, and I’m planning to build testing models for nearby wave-tanks, then my own hull, as well.