Apply Seasteading Concrete Shell Structures
June 5, 2011 at 11:29 pm #13716shredder7753 wrote:
… you expressed doubts based on the high cost of launching it… is it possible that we could rent 2 mobile cranes and do a tandem lift? … mobile cranes are available…
It is quite difficult to explain what a heavy lift operation requires, to somebody who is not familiar with the topic. First of all consider, what is above 20 tons a difficult manouver that needs expensive special solutions – also consider that “can lift” means 2m from the crane – not 20m from the crane center “can lift capacity is exponentially down with distance”. Also can lift means on a concrete plate – not on a beach. Also consider a 20min lift means 1 week of crane rent. Crane and 3 auxiliary trucks come in, bring material to stabilize the terrain, then counterweights to stabilize the crane, a crew to mount everything a auxiliary crane to crane the counterweights….
You get a better picture if you bring a representative of the crane company to your building site and ask for a quote for the whole manouver…you will be surprized how much it differs from your calculated 1 crane hour according cost table.
Calculate 2-3 times the building cost for “craning” a structure like a bergstead to deep water from the shoreline.
concretesubmarine.comJune 6, 2011 at 1:30 am #13718
i was thinking like 10-15k. this makes it sound like it would be more than 100k. ouch. back to the drawing board, for now.
“Leadership and do-ership are not the same thing”June 9, 2011 at 8:17 pm #13775
If you use a floating DryDock, or a drydock, or dig the beach around and under, then float it out… Last method has worked for centuries…
Never be afraid to try something new…
Remember, amateurs built the ark, professionals built the Titanic.June 10, 2011 at 3:04 pm #13787
Dig around and under ….This would be a launch from a graving dock…alternative would be build in a floating dock…
Keep in mind that the building of such a dock has a cost no minor than the cost of the structure itself – so these are MAJOR considerations at the moment of design and budget calculation that go far beyond “call a mobil crane for an hour”. This makes it so essential to come up with a construction technique that avoids that kind of costs to reach the desireable 331 Euro per cubic meter living space. (launch structure coast guard base)
concretesubmarine.comJune 10, 2011 at 3:31 pm #13790
video Ellmer! Very cool. I don’t speak or read Spanish, so how much did that cost the Ecuadorian Costies?June 15, 2011 at 1:50 pm #13801wohl1917 wrote:
video Ellmer! Very cool. I don’t speak or read Spanish, so how much did that cost the Ecuadorian Costies?
Interresting question, as it was a military proyect i doubth that they have a exact calculation of the cost . The military uses resources like “cost free labor” and “cost free yard installations” that a civilian project can not count with. In general terms the economic base conditions in ecuador are of lack of infrastructure and industry so you would have higher cement cost as in neighboring colombia, construcction of metalic structures and certified welding also tend to be more expensive.
If well mounted a building site as shown in the video can build at a general cost of 331 Euro( 474 USD)/ton structure building for concrete shell. I would estimate the structure to about 200 ton. To compare a steel structure would come at USD 5,5/kilo. (5.500 USD/ton)
The concrete float can be calculated with a maintenance free service life of a century or two. A steel structure under this conditions will have 2-3 years service life – to keep it going longer a expensive and intense maintenance shedule including dry docks is required.
Basicly the military in south america has a “seasteading problem” to solve. Their job requires presence in remote jungle, mangrove, and ocean areas where there is no access road at all, all access can only be done by water. Colombia and Ecuador therefore are developing floating military support bases.
I have been in bahia malaga military base where the colombian pacific interdiction surveillance is located admid what is a endless mangrove jungle swamp area. They have several meters of tidal changes – so beside the access problem the tidal problem forces floating structures for service installations.
No doubth we will see more floating military bases in this area in near future.
Ecuador floating base video1
Ecuador floating base video2
The merit of the ecuadorian floating base is that it takes the floating house concept to open water areas. What we see in video 2 is that the movements are quite unpleasent – so i would suggest to improve the design by increasing the “movement relevant platform diameter” in the sense of the seastar concept with outrigger arms to some 40m diameter which is a acceptable size according to the experience of the Nkossa barge.
concretesubmarine.comJune 15, 2011 at 6:51 pm #13840
it rides like s___. No keel, no ballast, low freeboard, a high suprastructure that results in a lots of windage and a high metacenter, just a square box (bergstead like) on the water. An example of how not to do it. The first 25 foot wave will capsize it in no time.June 15, 2011 at 8:44 pm #13842
It has a beam in the 20m range similar to container ships and warships – the metacenter seems lower than seen in that kind of ships – so i would not expect it to capsize in waves earlier than normal ships relaying on form stability do.
It rides like a 20m beam ship would do under the same ocean conditions – sufficient comfort for marine infantry – borderline comfort for civil housing. Incrementing the island diameter to 40m (nkossa size) would certainly stabilize the whole thing.
No doubth that the ecuadorian floating base is superior in seaworthyness to the Kon-Tiki raft – and remember – this raft made it over the pacific ocean. The freeboard is compareable to a modern yacht – the wave impact resistence of the superstructure is clearly superior to a yacht.
So if i had the choice to bet my money on can make it – or not – drifting over the pacific – i would bet on “can make it” (Video of Kon-Tiki drifting over the pacific)
concretesubmarine.comJune 15, 2011 at 11:05 pm #13843
about the same thing? The square box with a building on top, bobing up and down in 5 ft seas:)? http://www.youtube.com/watch?v=T_PfGDA0lPA&feature=player_detailpage. If so, I have big reservations about a Pacific crossing,….But that’s just me:)June 16, 2011 at 2:09 am #13844OCEANOPOLIS wrote:
it rides like s___. No keel, no ballast, low freeboard, a high suprastructure that results in a lots of windage and a high metacenter, just a square box (bergstead like) on the water. An example of how not to do it. The first 25 foot wave will capsize it in no time.
im wondering… could a berg use ballast water to reduce the rocking motion? that could mark a significant design improvement – credit to oceano. im not sure how a keel or a high freeboard would help for a moored structure tho.
“Leadership and do-ership are not the same thing”June 16, 2011 at 4:52 am #13849
The only way to get a significant improvement ( near cero motion in average ocean condition ) is increasing the beam to 40m (at least) – this excludes a “small scale approach” pretty much. Only submerged structures can be small and cero motion at the same time.
For surface floats the “more than 20m beam requrement” has no exception. Even a monster like a cruiseship in the (20m plus beam range ) still needs expensive dynamic stabilisation to create “keep coffee cup on the table” conditions.June 16, 2011 at 1:50 pm #13858
It looks to me like it simply needs a longer ‘wheel-base’ or hull as it were. It should be more… ‘ship-like’ perhaps. Make it longer with a bit more freeboard to ride over the troughs and put a pram type bow on it so the waves don’t pile up and break over it. Yea, thats the ticket!June 16, 2011 at 4:28 pm #13860
make it ship-like (or kitefloat:) will make a big difference. But @ least raise the freedoard on the bow and lower the height of the housing.
Also from the video,…the structure seems light to me. Change the underwater hull configuration, (that’s what I meant by “keel”-wrong term) instead of flat bottom to an inversed pyramid, so you can have ballast down towards the bottom (in grey). No water for ballast, too light. Lead bars, scrap iron, or just concrete block. Now you have less windage (by lowering the height of the suprastructure) = less heel = less rolling. Now you have a lower gravity center (the lead ballast) = higher metacentric height ( http://en.wikipedia.org/wiki/Metacentric_height ) = more compensation as a “righting force” = less rolling.
Since they are doing a Bahama style mooring, http://www.tropicalboating.com/boat-handling/bahamian-anchoring.html, why secure your mooring lines @ 2 different corner?? (check video). That will turn the flat side of the square into a “bow”, therefore the bobbing up and down. Secure both your mooring line @ only one corner, on a bollard (http://en.wikipedia.org/wiki/Bollard) or a anchoring cleat. Thus, your bow now it’s the 90 degrees corner and you will cut through waves, reducing pitch.June 16, 2011 at 9:37 pm #13863
The Ecuador floating coast guard base takes floating houses on concrete bases out of the protected space of rivers, lakes, and marina installations and puts the concept into unprotected open water.
The videos of the base ( launch / wave motion / building ) suggest that the wave movements are sufficiently stable for marine infantry but not for civil housing. It also sacrifices completly the concept of mobility. For mobility and wave response a bow on the structure would be an improvement – a concept that has brought “maximizing the beam” and “featuring a bow” as far as you can get is the “triangular flat float” best represented by the “WHY yacht”
I would start with a triangular concrete flat float and build it up from there – instead of a ugly square house i would put some “futuristic concrete shell” as superstructure. The look and feel of the floating home should be something like this (video).
As seen on the Kon-Tiki video, flat floats with a low metacenter, are very stable structures, with a good wave response in general, and nice mobility. (Kon-Tiki)
concretesubmarine.comJuly 24, 2011 at 12:29 am #14280
ocean i think we both agree that a square float that does not have a “bow” should be tied to a corner, such that it reduces wave motion.
also, when you watch the video of the coast guard base wave action, you have to compensate for the boat that the camera is on. that boat is bobbing up and down too and makes it seem worse. actually, the base itself is not rocking any more than a typical boat of similar size. and another thing is that their float has a building on top, where my designs have the large majority of their center of gravity below the surface. im no expert but my guess is that it would be better that way to reduce motion.
“Leadership and do-ership are not the same thing”
The forum ‘Structure Designs’ is closed to new topics and replies.
Posted on at
Written by ellmer