Cost of building a floating construction facility


#62

Sure. At very high maintenance cost.

A floating construction facility is of no value to me. A seastead is valuable to me.

LOL, if you want to operate a construction facility made of shipping container you will be living in a container.

Really?? After 25 to 35 years, the cost of refit goes up significantly. You’ll hear some people state that you should carefully inspect the interior of a steel boat well, because steel boats rust from the inside out. While you should certainly inspect inner shell plating, frames, stringers, and other unseen metal components well for results of trapped moisture, not properly primed/painted steel, etc., this isn’t the full story. Steel rusts from the inside-out. Not from the inside of the boat-outward, but from the inside of the plate to it’s surface layers. The plate can look normal at it’s surfaces, but when you cut into it with a torch, you see the metal bubble up when you hit on the oxygen.

But don’t let anybody stop you. Go ahead and build it.


(Larry G) #63

Citation? Because I believe you are mistaken. Does a basalt rock have less tensile strength than a similarly-sized piece of concrete?

Your point based upon your assumption doesn’t accord with observed fact about ferrocement (steel has more elongation before failure than concrete as well, and yet you don’t see ferrocement structures failing due to “zero tensile strength in the steel until it is under strain”), and you have made no logical connection between your assumption and either cited or observed fact.

This illustrates a complete lack of understanding of the point actually being made. Basalt rebar is flexible. Your focus is in elongation. I get that. I believe you are incorrect about tensile strength, and you haven’t cited a source to back up your assumption.

My point, however; was not about elongation at all. Basalt rebar comes in coils under tension. When you uncoil it, it goes more or less straight but remains flexible. If you make a curve with it (like a sheer line) then it is under tension, not longitudinally, but horizontally. The sharper the curve, the more tension. If you don’t compensate for that, then you have internal structural members under tension in opposition to the embedding matrix of cement. You wouldn’t want flat steel plates forced onto a curved structure and then tack-welded into place without being shaped, either. Tension in the plate would work against the welds.

One way to eliminate that tension is pre-shape a thermo-plastic epoxy matrix of the ‘rebar’ using heat (JL’s suggestion in an older thread) and/or embedding the basalt fibers in a pre-shaped form before adding the epoxy matrix.

So the lesson here, amigo, is you appear to be so certain of your own opinions that you are not paying attention to the actual point made by other people, nor according them simple courtesy or benefit of the doubt when your own comprehension falls short.

It is an Internet forum, a certain amount of empty opinion is unavoidable. We don’t have to add to it unnecessarily.

This is simply not true. Corrosion can occur even when zincs are used, and it is not an insignificant expense or effort to maintain them, particularly on a larger vessel. Corrosion is greatly reduced when sacrificial anodes are used, but not absolutely eliminated. A steel hull will not last decades without zincs, it can corrode trough the hull in months or single-digit years.

Note: aluminum alloy is used as much as zinc now. I’ve done several dive jobs replacing these in the last year.

Because geopolymer is a relatively new material, is not as widely commercially available, and too many people assume that it is the same as Portland cement (including materials limitations), and that Portland cement’s positive attributes are outweighed by it’s drawbacks despite this opinion probably mostly being influenced by inexpert implementation as much as materials limitation.

But the main question was about basalt, not geopolymer. I brought geopoly into the conversation because it has better tensile strength and flexural modulus than OPC. And every few percent helps.

Note: I have no objections as to the viability of using basalt fibers rather than glass fibers in epoxy matrix for a fiberglass-like hull. Newer resins have increased UV resistance, better materials characteristics than the past, etc. But it will require significant expense and effort for maintenance haul-outs over time.


(Larry G) #64

Emphasis added.

So the better question if we’re open-minded, would be:

Is cement (OPC or Geopoly) strong enough in tension, to withstand forces applied to it until it is within the range where the basalt fibers reach sufficient tensile resistance to further stretching to take over the load?

In other words, we have a situation like a dock snubber.. Does the rubber section (cement) stretch enough that the rope (armature) can start taking the tension, or does it break before the rope gets the load.

In the case of cement and steel armature, practical experience shows that the steel in ferrocement boats does take the load before the concrete fails. Basalt is stronger (ultimate tensile failure) than steel.

This is the proper line of inquiry: Does basalt fiber have a higher ductile deformation curve (is it “stretchier”) than steel? If so, is that ductile deformation curve within the parameters that the cementitious matrix can handle?

And the practical experience answer to that last question is “yes”.

What am I basing that on?

Glass fibers have also been used and approved in OPC to provide tensile strength, ergo, basalt would work.

Glass fibers have almost the same strength and stretch properties as basalt fiber, enough that ASTCM building codes allow for using them interchangeably, even though it is acknowledged that using standards for glass fibers applied to basalt is overly conservative due to greater tensile strength and temperature resistance of basalt.

Since silica glass known to cause gels in OPC (and weaker overall compressive strength), geopolymer would be even better because it doesn’t form gels with silica, it incorporates it into the long chain molecule. Therefore geopolymer and basalt is even better.


(noboxes) #65

My drink went out my nose and all over the keybd when i read that one. Not to worry, it was only water.


#66

The answer is very clear the snubber breaks first because its elongation% before separation is so small.

Any cracks refute that practical experience.

You have it backwards, basalt is not as stretchy and that is a good thing. Basalt is better than steel, but steel is easier to pre stretch.

Also the codes you are referencing are for supported compressive loads only.

The question you really want to answer is how far can the concrete flex before cracking and then make all of your designs twice as strong as your worst case scenario. Euler-Bernoulli Beam Theory is your friend.

This is the same analysis every building design has to go through, regardless of the material used.


#67

A basalt rock has entirely different physical properties than basalt fibers. Do you really need a cite?

A crack is the failure of the steel to hold the concrete together. I see cracks in steel and fiber reinforced concrete all the time.

Dunning Kruger Effect?


(Larry G) #68

But is it a failure of the structure? Micro-cracks in ferro boats don’t necessarily sink them or mean a failure. They don’t all go completely through, the armature supports the structure even with micro cracks, and to some extent it is self-healing. Read the Hartley book. Several decades of practical experience, and it specifically addresses cracks.

Cement boats work. Many other floating cement structures work. No matter the misguided theory, they still float. For decades. With less hull maintenance than steel, or even poly.

That’s my point, but I left it open to the question of which stretches more. The big thing is does it stretch too much? The answer is clearly, “no”, because it has been done and and it doesn’t. “Pre-stretching” (pre-tensioning) is a good technique, but it’s not necessary to make a ferro boat float for decades (as demonstrated). There is also post-tensioning, and designs that don’t rely on tensioning the armature at all.

Which material is “best” relies upon many factors other than and in addition to the material’s physical properties.


(noboxes) #69

There’s floating concrete bridges in the northwest usa, carrying interstate highways even, the Lacey V. Murrow Memorial Bridge. Also see: Evergreen Point Floating Bridge, Hood Canal floating bridge.


#70

The nice thing about all this is that each of us can have our own design, our own specs, make our own informed choices (or even just follow whatever we think sounds best for us), and try to get OFFSHORE.

Unlike those asking for funds to build their dream seastead, I want to finance a place to BUILD Seasteads. I don’t NEED someone to dump Million$ of Dollar$ into my account for that (though I wouldn’t object, either). I COULD use money to get the down-payment and closing costs covered, as well as help setting up the facility, though. Sure, what I have picked is shallow, but it has direct access to the Gulf of Mexico, from a relatively sheltered saltwater ‘lake’. Size and draft limits apply, but it should even be able to be dredged.

Short of building where I am, making sure it can be trailered to the Gulf of Mexico and launched, it’s about as close to a workable idea I’ve been able to come up with. I’ve tried to get info to rent large enough facilities, but the expenses were ridiculous.

At the same time, it allows a land support base for whomever builds, launches and remains in relatively short distances from that build site. Mail service? Parcels? Truck loads of building materials? Park a car, take a runabout to the seastead and not worry about outrageous fees? Setup for routine grocery deliveries? A whole host of options you cannot get easily, by just launching and leaving… Not to mention a place to return to for maintenance and repairs…

@katontri wants to be able to build, get offshore, then, build for for others, if she can get her floating shop going. Even she will need some access, like that.

Personally, I don’t care WHAT someone wants for materials, or much about their specific design. I do, however, care that it be relatively safe for whomever is planning to live ON it, and those that visit… Hard to have a working relationship with folks that build, go out, sink and die…


#71

Nope a working bilge pump and you are good to go : )

Of course, concrete is wonderful for big stationary projects, like floating docks, anywhere weight and compressive strength are needed.


(noboxes) #72

Tsk, tsk, tsk, you are all still in the monohull box, aren’t you?


(George Hawirko) #73

Yup, there are others, try this thread of post I authored a piece back in time, EPS Composites - Investigating Polystyrene Concrete Composites


(noboxes) #74

In usa, bare EPS foam is not allowed in the water any more. And freon-expanded foam isn’t made, they forced the local site to switch to steam, so they closed the business, and all EPS foam floatation was removed from the lakes.


(George Hawirko) #75

Well finally we have progress on such a common sense problem.


(.) #76

What is better a catamaran or a trimaran?


#77

Neither, a Proa is the best : ) Always fly an ama.


#78

Opinions…

Better to try to get experience on the variants and make up your own mind.


(noboxes) #79

I think that depends on how fast you want your factory to move, and how stable you’d like it to be in the waves.


#80

For a factory I would prefer a dead level steady floor, environmentally controlled, large storage and work areas, definitely a catamaran beached on a gorgeous tropical island.


(noboxes) #81

Looks like you decided on a catamaran then! You found an island with a flat and level beach for it to sit on?