What about the waves!?!


(Bart Kemper) #30

How about we dial back the tone a bit. I’m an engineer. I’m in the Marine Technical Society and Society of Naval Architects and Marine Engineers. I have dealt with failures in mature technology embodiments. This is not such.

So… if you have the answer: what is the first mode of failure for cyclic loading based on standard seas as a basis for infinite life and then a 5x design margin for a worst case storm season all for the site in question. Coupled with this, what is the corrosion prevention scheme for stress corrosion cracking? What is the maintenance cycle? What are the field tools proposed? What is the reliability scheme?

NONE of this is trivial, especially since the other sections indicate the majority of the people involved are “passengers” as opposed to working, trained, skilled crew.

If you are going to be rude and act like you have the answers, give it up. Show me. If you don’t have the answers, then they are not addressed, they are talk about and are put on hold for a later time. These issues are life and death.


(Matias Volco) #31

I’ve gotten all of that from the information available online.
would it be polite to post relevant links? As a seasoned engineer would you prefer to revisit all of your questions in a single post abridged for you personally, or to see the source material?


#32

I believe what the man is asking for is an engineering spec.

That would be interesting for you to supply. What are the materials, hull thickness, gross weight and draft for your crescent shaped housing structures? What about the round domes?

In my post about optimal draft, I brought to question whether deep draft structures (concrete shells) are preferable to shallow draft (polymer/foam based shells).

It would be interesting to see your calculation as to shell thickness and weight. As you know I supplied mine in full.


(Matias Volco) #33

There are dozens of threads in the old and current forum that address materials, concrete specifically,

The public should be aware that JW is talking about a calculation(s) he made for his novel, which is in fact poetically relevant to the plot. My visualizations are just illustrations, extrapolations, of what can be done using standard marine concrete construction as found in large existing projects, and smaller projects and experiments, in real life.
All of the above can be supported with relevant links, which I’m still in doubt whether it’s polite or not to (re) post.
We’re very far from the waves at this point so Mati out


#34

DIY is going to tend to be significantly cheaper than anything commercially built and produced. Consider 20% of the cost of a commercially built yacht is the hull, and half of that is labor.

Now, turn it around and pay 10% of the commercial cost to build your own hull, and even 40% to equip it exactly the same, and you’ve saved 50%.

My own concept comes in at ~$100/sq ft. 15% the expected cost for the TSI Barge, and I get to put it where I want it.

Part of the plan is to incorporate the same type of passive/active flooded chambers, for additional pitch/roll/yaw control that has been retrofitted to one of the PGS Ramform vessels. The chambers are open to the water, from below, partially evacuated, and linked by airways, to shift air around, rather than try to pump high volumes of water.


#35

Great plans here. Although I still question why the shaped hull rather than a simple rectangle. For a non-moving structure I’m not sure why the hull needs a shape at all.

Instead of the flooded chambers, why not just use gyroscopic stabilizers?

Check out this video at 1:12 - the left boat has the stabilizer


#36

The flooded chambers are interconnected to allow air-flow, creating controlled, automatically variable ballast w/o additional power under most conditions, yet allow powered control, for stability in severe conditions, with minimal moving parts.

Gyro stabilization requires constant power and constantly moving parts that wear and need repair and replacement.

A shaped hull can weathervane with changing conditions… Part of my goal is to moor in a current, but also to weather storms, which can come from any direction. Being able to weathervane allows the hull to function properly in higher wave-states.


#37

Would you please clarify this for me, Jeff?

I’m visualizing a floating “bottom structure” located in deep water … that somehow refracts surface wave energy between bottom and mid-level layers.

Is this correct, or did you mean something different from that?


#38

@BobDohse
I posted it in the Breakwater thread…

Another article on the subject…

For years scientists have been looking for ways to make invisibility cloaks a reality, by shielding objects from light and other electromagnetic waves.

But what if we could make floating objects, such as an oil platform or storage tanker, invisible to physical, water waves? Professor Mohammad-Reza Alam may have found the answer.

Alam, a fluid mechanician, and his team of researchers at the University of California, Berkeley, have come up with a technique to make these structures immune to the up-and-down motion of rough seas.


Combined breakwater and wave power generator
#39

Broadband Cloaking in Stratified Seas
Mohammad-Reza Alam1
1
Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
(Received 13 September 2011; published 23 February 2012)
Here we show that floating objects in stratified fluids can be cloaked against broadband incident waves
by properly architecting the bottom corrugations. The presented invisibility cloaking of gravity waves is
achieved utilizing a nonlinear resonance concept that occurs between surface and internal waves mediated
by the bottom topography. Our cloak bends wave rays from the surface into the body of the fluid. Wave
rays then pass underneath the floating object and may be recovered back to the free surface at the
downstream bearing no trace of diffraction or scattering. The cloak is the proper architecture of bottom
corrugations only, and hence is surface noninvasive. The presented scheme is a nonlinear alternative to the
transformation-based cloaking, but in the context of dispersive waves.
DOI: 10.1103/PhysRevLett.108.084502 PACS numbers: 47.35.Bb, 47.11.Kb, 47.20.Ma, 47.55.Hd


#40

Due to the design similarities, it might be worthwhile to explore the Japanese Pufferfish ‘Mandalas’ as a basic pattern for the layout of bottom structures, for the calm-zone surrounding a seastead…


UK Physicist wanting to learn more about seasteading
Combined breakwater and wave power generator
UK Physicist wanting to learn more about seasteading
#41

@JL_Frusha … Thanks. I found a more recent paper on the “Wave Bridge” … written for open seas, as opposed to shallow-water application.

It also addresses the problem of hortizontal force that I raised in the “Breakwater” thread.

Btw, Richie Sowa addresses this problem with his “flippers” scheme … which transfers surface waves into propulsion. Not currently practical, but creative.

My perspective - this “Bridge Wave” concept intends to be minimally invasive to the oceanic environment, which probably isn’t necessary unless national environmental regulations mandated it for some reason.

IMO, a floating mangrove forest or a kelp field accomplishes the same objective (of surface wave refraction) at a cheaper cost, and probably with better additional benefits.


Combined breakwater and wave power generator
#42

How a’bout them apples…? I proposed using parabolic defection, somewhere in this forum. Be ripped of I remember when, where, or what, but…


#43

EFFICIENT LONG-PERIOD WAVE ABSORBING SUBMERGED MOUND STRUCTURE
Masashi Tanaka, Akira Matsumoto, Minoru Hanzawa

Abstract

In many Japanese ports, it has been reported that long-period waves with periods of 30 to 200s cause serious problems in cargo handling. As a countermeasure, wave absorbing mounds installed on the harbor side of breakwaters have been constructed. The crown heights of such rubble mounds are almost equal to those of the caissons. Although such structures can be expected to provide some wave absorbing performance, they are too large to apply to specific site conditions. It is important therefore to reduce the size of the structure to apply to specific site conditions. In our study, a slightly submerged mound type long-period wave absorbing structure is proposed. A series of hydraulic model experiments was carried out to evaluate the wave absorbing performance in port and stability characteristics of the armor units against wave overtopping from the sea side. Throughout this study, it became clear that submerged structures display a higher wave absorbing performance compared with those of conventional structures. Moreover, a prediction formula for the stability number for Tetrapods covering these submerged mounds is proposed.

https://icce-ojs-tamu.tdl.org/icce/index.php/icce/article/view/7725/pdf_872


UK Physicist wanting to learn more about seasteading
UK Physicist wanting to learn more about seasteading
#44

Conversely, the shell could be inverted and floated on the surface. That would retract surface waves regardless its orientation.

Compensating for hortizontal force remains a problem, as it does for any surface structure.


#45

I’m not exactly sure what “electrolysis seacrete” looks like in practice, but a “shaped wire-mesh form” is also a practical means of scattering surface waves.

Deployed horizontally, a flexible mesh would dissipate energy much like a kelp bed or mangrove forest.


#46

A additional factor in that concept, Jeff, is that surface waves refracted downward onto a submerged structure, by definition, help (slightly) to compensate for drift from the hortizontal force inherent in surface wave refraction.

However, I would refract from the submerged structure back toward the surface and into the incoming surface waves.


#47

Biorock/Seacrete uses the electrolysis of seawater to cause accretion of Calcium Carbonate onto electrodes. Water current and duration of the supplied electricity affect the rate of deposition, as well as the total amount. It is possible to create structures as strong as bone, that are also active environments for natural sea life, such as corals. Essentially, make an artificial reef, of almost any shape. One project is attempting to make a boat hull, another proposes to make a floating concert hall.

My suggestion is to use the same process to make hollow Tetrapods, or Crablocks of appropriate size, to create the seafloor wave-break, position them, and fill with sand/mud from the local sea-floor.

https://lh4.googleusercontent.com/s2FrXVEhUzwkQY_Imyx4lN16M01NJHgK7UGZP9d80clZYK44xvT_jiCxugskmWv0uZWSjX8GUfTkWA1g_JzdX_2kA59EmpJ2XBFhpGCakLXn5MktvdPhdvz-jDKochuT78O4SmE


Combined breakwater and wave power generator
#48

Thanks for that update, Jeff.


#49

Earlier, possibly elsewhere, possibly in another thread. I tried to suggest a breakwater that reflected the waves back on themselves…

Here’s one design that does… Notice it is moored in a fixed position…

Floating breakwater Gokova Ören marina, Turkey