Aspiring adventure builder?


A bit about my background:
American born, raised from 11 yrs old to graduation from high school in a communist country.
My degree is in philosophy, but I was a couple classes and a senior engineering project away from a degree in civil engineering. I have, at various times, worked in IT, apprenticed as an electrician, and currently teach high school math.

I can read and write French, though it’s a bit rusty these days.

I got interested in the seasteading community largely because the boat design community is a bunch Old Retired Codgers (ORCs, I like to call them), and don’t have the vision for concrete sailing catamarans that I do.

Speaking of which, I did a study of Ultra High Performance Concrete (letting engineers name a product is just as bad as letting marketing name it) during my time in engineering, and I think pozzolanic concrete with some modern reinforcement has the potential to make for a really cool seagoing vessel.

(.) #2


The background is good enough.

Concrete sailing catamaran is interesting. Where do you want to build it, and
where do you want to keep it?

(.) #3

(Wilfried Ellmer) #4

@dsigned001 |

• would you be interested to explore a joint project ?

• If yes - what is your framework ?

• If you are not in comfort to talk this on a public forum please contact me over the private message funcion of the forum

Wilfried Ellmer | nautilusmaker | oceanic business alliance |

Workhypothesis : Advanced Cement Composites are light and strong enough to build a high performance Catamaran out of it - on a incredible low budget…it just needs a builder to get it right…

Our suggestion for a suitable composite construction material to perform this task...


What did you have in mind?


Well, the first one will be pretty small. A tunnel hull puddle duck to take my kids sailing on. But the end goal is a 53 ft narrow beam cat. It will be built somewhere along the coast of the gulf of Mexico, I’m going to venture Houston or maybe Corpus Christi. Not sure where I’ll keep it, but I’d like to kick around Latin America for a few years before eventually ending up in SE Asia.


Just wondering, what would be the point of a narrow beam cat?


There’s this idea in catamaran design that you should “balance” the transversal and lateral stability that seems like it’s not terribly well suited to cruising, for a number of reasons.

Firstly, the ways catamarans capsize (or rock, or heel) isn’t the same forward to back and side to side. Burying a hull in a swell is much worse than blowing over. Moreover, blowing over is quite easy to prevent: don’t run overcanvassed. But burying a hull is a function of your speed versus the wave size (all other things equal). So, for my money, I would much rather give myself the extra LOA, and not have to worry about endo-ing.

Second, your cost goes up dramatically the wider the cat. The strength of the structure is dramatically different. So, to make a bigger cat, rather than making it according to some arbitrary ratio, factor in the cost, and the carrying capacity, and the righting moment.

Third, the people that I can see who actually have the ability to make catamarans to suit themselves, and who actually like to sail them around, tend to go with a longer, narrower cat. Wharram, Bob Orem, and one of the couples who built one of Richard Woods catamarans (that he has as exemplars on his website) actually went through the trouble of lengthening their catamaran. These aren’t people who are looking to break records, not really looking to impress anybody but they do want to do passage making and like moving about in cats much better than monohulls.

Finally, I think it’s potentially a much better solution for getting accommodations in marinas. The limiting factor in most berths for a catamaran is the beam, not the length, and a cat (if it can fit in a berth at all) is going to be taking up all the width, and not much of the length. I think it might be a better idea to design a cat to fit a certain standard berth, rather than something that looks good in press shots but that you have to park way out at some mooring because there isn’t any place wide enough to park (or there is one, but you’re going to pay megayacht prices for).


Even so, narrowing a cat to a monohull beam to LOA ratio defeats the purpose of building a cat, stability and live aboard accommodations.

How is this personal project of yours related to seasteading?


I would take issue with two parts of this:
Firstly, a tunnel hull of identical beam and LOA to a monohull is still dramatically more stable than a monohull. In fact the first catamaran to be banned from competition was such a craft. That said, it doesn’t need to be the length to beam ratio of a monohull sailboat. It could also be the length to beam ratio of a trawler. A Grand Banks 53 has LOA to beam ratio of roughly 3:1, which is roughly what I’m aiming for.

The second issue I would take is that the purpose of building a cat is limited to stability and live aboard accommodations. These are mostly true only if cost is not taken into account. Accommodations are much more affordable on a large monohull, for one thing. That is, you can generally afford a larger monohull than a catamaran, unless cost is no object (which for most people, it absolutely is). But the bigger issue is that you’re ignoring the bigger reason to build a cat: speed. Even a tunnel hull is much faster than a monohull, all other things equal. And again, there are some seriously fast cats built like this. The Gougeon 32 comes to mind.

As for the relation to seasteading: I came across the seasteading website due in part to the suggestion of a redditor when I was talking about using concrete. The sailing community in the US is pretty snooty when it comes to build materials.

That said, sailing catamarans could be scaled to incredibly large sizes. The main prohibition is use cases and cost. Using a cementitious build material would do some significant work on the cost front (says I), and seasteading would be a use case. That said, there seems to be a large subset (majority) of the seasteading community that wants to build what amounts to floating barges. For my money, having the option of pulling up stakes and moving is an advantage not easily cast aside, especially when a catamaran is perfectly serviceable as a stable platform if you’re in a harbor.


True, WorldCat comes to mind. But up to what sea states? In 120 knt I’d rather be on a Hans Christian 48…

That’s about right. I’m a bit higher in beam, 3:1.3

I stand corrected. But in the seasteadingverse speed is secondary to long term accommodations, that was my rational,…

I agree. Mobility is paramount (says I) and a “cat like” seastead design would make certain sense.

Still, cost is an important factor,… A “barge like” seastead-floating-island will still “get there”, for a fraction of the price,…

(Wilfried Ellmer) #12

… this brings it absolutly to the point…it is the cost factor that inhibits materials like epoxi composites (and other yacht materials) to be deployed in “building size” anywhere on the planet in important scale.

…advanced light cement composites are a gamechanger…it is about “disruptive developments” and new development steps on the evolutionary line to seasteading.

Today´s yacht market operates within a cost per real estate square-meter frame of up to USD 23.000/square meter
Advanced light cement composites have a potential to pin the cost per real estate squaremeter in the range of USD 50-800 (depending on the building method) - that is of essence - in fact it is a different planet in a different universe.
And this "different universe" opens a wide range of "not yet explored possibilities"...

(.) #13

Good choice. I am not near to the Gulf of Mexico.
I would think; it is not so hard to anchor somewhere there.

(Wilfried Ellmer) #14

I have no preconcieved way how to cooperate - i run a network centered in the caribbean - doing what you find when you google up my name - anything that makes sense is possible…

From what you have said here so far - exploring the topic of some form of cooperation seems to be interesting…

We could start with you telling me the framework you plan to develop your project in…and i telling you how i think my network could support you in the venture…

I need a clear picture if this is a "phantasy of yours" or a "real project you are working on" - because these are different things ...


Ah, there’s the rub! It’s somewhere in between, I suppose. I have built several test panels to test various locally available materials, and have cut the first couple of panels for the little puddle duck just the other night. With that said, I currently reside in a land locked state, work a 9 to 5 job and have three small children. I don’t have investors or a business plan to commercialize anything. If you’re looking for a concrete guy to do seasteading stuff, a bridge engineer might be a better bet. The fastest and most successful concrete sailboat I’m familiar with was called Helsal I, and the guy who commissioned it hired a naval architect and a structural engineer who specialized in thin shell prestressed concrete. The boat was comparable in weight to the boats it was competing against and perhaps more importantly, beat them.

I’m not looking to discourage you from collaborating with me, and if you know investors who can pay me enough to eat on, I’d happily turn this into a full (or part) time gig. But right now I’m just sinking my own very limited time, energy and money into the idea.

EDIT: I should also mention that I have done a fair bit of actual research at this point, so the project may have graduated from “fantasy” to “feasibility study”.


Neither am I: I’m in Colorado at the moment. But I have family connections down in Texas, and the American gulf coast is about the cheapest real estate you can get in the US with easy access to the sea. I don’t know much about how difficult it is to source some of the more exotic admixtures, but even in the US their availability varies quite a bit regionally (unless you want to pay shipping, which eats quite a bit into the low cost of the project).

(noboxes) #17

No no no, Ellmer is looking for you to give him grant money, forget about investment money with contracts and repayments and such. Lets not forget he was kicked off boating forums, and has been banned here several times for spam and advertising.


Can’t say I’m shocked

(Wilfried Ellmer) #19

@dsigned001 | i prefer to take our conversation to a interference free space…i am not interested to have my conversations agressivly interfered and interupted by the segment @noboxes represents.

so what makes sense to you....from what you have said so far, i assumed that you have graduated to feasibilty study already...
if you are seriously looking for living and building in the caribbean - this is within the frame i can offer...
Your post | | was useful to make some progress on the task to figure out what is your "project framework" - you noticed i have not walked away and closed communications - so - i see ways of feasibility...