January 10, 2010 at 5:05 am #1167
Most barges are not suitable for open ocean operations. There is one barge design that is known to be sea worthy however. Small and large barges have been discussed.
I’m looking at this option. We need a city centre to our free sea steading communities.
Its Noah’s ark. Various models of the ark described in the bible have been wave tested up to catastrophic waves and it does not fail. The Dutch use a one 20th scale barge with its parameters to take cargo’s up and down their coast, that’s in the North Sea.
The key parameters are: It was 300 cubits long, 50 cubits wide, and 30 cubits high. Taking the cubit as 18 inches, a fairly conservative value, the Ark was 450 ft x 75 ft x 45 ft. That’s 137 m x 22 m x 13.7 m. 24000 tons estimated freeboard. http://www.creationconcepts.org/resources/ARK.pdf
In scaled wave tank simulations it does not roll much or rock bow to stern until the wave heights are a third of the hull hight. It is stable but moves in waves up to 80 m; the equivalent of huge tsunamis bow on. The bow and stern must be rounded and very high and the deck must be sealed so wave wash can’t drain inside. The bible indicated this in the account. It had windows but they had to be openned to let out a dove.
An arcology version would be concrete, ferro-concrete, with rubberised plastic sheets not gopher wood [laminated wood] and pitch. The top hull would be plastic or reinforced plexiglass. My preference is ethylene tetrafluoroethylene (ETFE). I would recommend the top greenhouse deck be garden, hydroponics with atrium to the lower decks. Residential accommodation would be on the middle deck with some living space woven into the garden deck. The lowest decks would be plant, factory, storage, Aquaculture and intensive hydroponics under artificial lights. I expect energy will be abundant. Various propulsion options include kite sails and tug boats. We need the latter anyway.
The vessel would have more space than any liner because I would only load it to 50% its load capacity: 12 000 tons.
This would be a city centre not a sea stead but it would serve as the commercial heart of a sea stead community and a major manufacturing centre. It would accommodate about 1 to 3 thousand people.
I would also build a second version with no green house and minimal accommodation. This would be used for heavier industry. It would have separate bays in both but in an industrial these would be more substantial with built-in water cooling in the firewalls. The stern bay could be a dry dock making smaller sea steads or modules 12 of which could be bolted together to make another Noah’s arcology.
I’m working up some images. You don’t have to believe in God or creationism to use the stability that we’ve discovered for this vessel.
For everyone’s information I was involved with the original Oceania Project in a small way. I’m also in several space organisations. And I have a Degree in sustainable Development, sustainable agriculture and renewable energy,water and sewerage.January 10, 2010 at 6:52 am #9147
Here’s a possible plastic for the top…http://dsc.discovery.com/videos/mega-engineering-a-magic-dome-material.html
I started a thread on it, in the Engineering section of the forums. Also. I’d suggest looking closer into the methods and materials they used in the barge. Granted, you’re not considering the same weight, but they used similar dimensions, without the bow or stern you’re talking about. Also, they used pre-stressed cables, to reinforce the structure. Well worth the effort, for something that big.
We had a tennis court built, using that method. Have had no problem with the slab at all. After it was built, the weather got nasty and the corners got severely under-cut. Had folks pack more soil in the space and haven’t had a problem with that, since the grass finally grew in. Point being, it was supported by the pre-tensioned cables and didn’t break.
You have a bit shorter overall length, with about the same height and width. I’d be willing to bet their concrete is a lot thicker… If you want it to last, I’d use their specs. on that and their methods. You don’t intend to approach their loads, but you’ll have different wave characteristics, than them, with the shorter length, plus, they have more ballast… You’ll be higher in the water, with a significantly lighter load. Might slide over the stuff that would sink Nkossa…
As for that ’1 life’ bit, betcha some dummy dives off the top and either breaks a neck, or drowns, or some-such, before anyone even knows it’s happened… Yes, people do it every year, cliff diving. Some don’t come back.
Doesn’t stop me from wanting to build something that’s at least as tall. Already looking into it, as a matter of fact. It’ll be a bobber, and handle 30 ft. waves and up to 90 ft. swells, not gonna be a fun ride, but… A bit like the proverbial hollowed-out tree, of Norse beliefs. The first man and woman created , Ask and Embla rode out the flood in it.
Understand, I’m not starting a religeous war, here. Different beliefs, different methods, same basic result. Look-up the “Flip Ship.” Almost 50 year old research vessel, still in use(launched in ’62). They used steel. I’m with you, on the ferro-cement!January 11, 2010 at 3:58 am #9168
Actually the plastic you mentioned is mentioned in my post, but I used the proper name and have bookmarked the manufacturer. I’m checking with them soon to ask if its salt tolerant and marine safe [non toxic in contact with sea water].
I want to go full size with the ark based arcology because I think we will need such things. It wont be a first generation sea stead and it will have more constraints than a small group sea stead. The more people you have the more rules you need.
A one fifth scale unit would be 90 ft x 15 ft x 9 ft. That’s ~27 m x 4 m x 2.74 m. About the size of a long bus. It only gives you one deck not counting the bow and stern castles. It would be good for seas up to 3 meters or so.
Pre-stressed concrete is a good idea but I’m hoping we can do it with a non corrosive material. Glass fibre ‘rope’, titanium, aluminium or carbon fibre. All are getting much cheaper. See the wiki on materials for discussion on reinforcing concrete with various non corrosion susceptible materials.
For everyone’s information I was involved with the original Oceania Project in a small way. I’m also in several space organisations. And I have a Degree in sustainable Development, sustainable agriculture and renewable energy, water and sewerage.January 11, 2010 at 6:15 am #9169
Your 1st post sounds very much like you’ve already tested a scale model and intend to build a full-sized, pack ‘em up Noah, one more time, ferrocement Ark.
Now you’re down to an oversized bus. That I can ball park, though I’m no engineer, much less in ferrocement. I have read a few books and would suggest the Peace Corps handbook on Ferro-Cement, for starters. It won’t be a perfect idea, but it’ll help give you an idea of what’s right, not a guarantee.
You’re down, to roughly 8″ thick sides and more than that on the bottom. I’d say the walls should taper to that 8″ at the top, be a bit thicker at the bottom. It might need built-up ribs across the bottom, or even up the sides. Pick up some books, do the basic reading and find a ferro-cement group to chat with.
I’ve seen sloops with 2″-3″ sides. I’d expect the main keel reinforcement to be of 2″ pipe, basic form re-bar at 1″+, some 3/4″ re-bar, ondown to 1/4″ and multiple layers of chicken-wire and or expanded metal lath, probably shot-crete applied mixture. If you’re lucky, it can be built in the off-season.
Like I said, it’s my idea, based on what I know about it. Closest I’ve been to building Ferro-cement was an overflow dam. 4′ thick slabs, up to 2″ rebar, hand tied. Thank the Gods I was on the carpenters’ crew!
Search the Internet. Bet there’s a website that can point you in the right direction, recommend books, maybe even a boat-yard. Once you get a Ferrocement engineer on-board, get some spec’s laid-out, you can get an idea of what your power requirements will be. Don’t let them BS you, if they build Ferro, they’ll have names of happy customers you can contact. Check marinas, look for folks that have Ferrocement boats. Ask them. It may not be easy to spot a Ferrocement boat. Never hurts to ask the dock hands or Dock Master. They are more likely to know who has what…
I think there was a company building trawlers out of Ferrocement, in Africa. If so, seems they had one that was about this size and powered with a Chevrolet 454!
Good luck on your mission!
If you can’t swim with the big fish, stick to the reefJanuary 11, 2010 at 6:24 am #9170
Had to edit, My head didn’t register 15′ I got bus-sized… Sorry.
If you can’t swim with the big fish, stick to the reefJanuary 13, 2010 at 4:48 pm #9205
with Almighty God as your marine engineer you can’t go too far wrong! Check out the Dome idea link for more on concrete construction…January 14, 2010 at 3:20 am #9209
Read this, for info. Have an expert do your structural design and possibly build it, as well. Get into some of the boating groups and get opinions of builders reputation, in Ferro. Like I said, use a reputable designer and experienced QUALITY builder with a good rep. for good work.
Outside that, it’s your puppy, though I’d make sure it has power and steering, with a good anchor system, as well as cleats built into the ferro rebar.
If you can’t swim with the big fish, stick to the reef
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