Shipping Containter Sailboat.

Discussion in 'Sailboats' started by bhoult, Jan 10, 2012.

  1. bhoult
    Joined: Jan 2012
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    bhoult Junior Member

    So I just finished a blog post about an old idea I had about making a couple old shipping containers into a sailing catamaran. I finally learned a 3D pakage so I could make some designs to play with. I thought I would search again to see if anyone else had done this and found this thread here:

    It would not let me add a comment since the thread was too old, so I am making a new one to ask if anything has changed in the last couple of years.

    My blog is here:

    I figure a boat design forum would be the right place to ask.
  2. DCockey
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    DCockey Senior Member

    What sort of waters would this be used on? Offshore, near-shore with protected anchorages readily available, inland ????

    You might want to estimate the total weight, and then how big the bundle-of-tube hulls need to be to support that weight. My guess is the hulls shown are considerably undersize.
  3. michael pierzga
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    michael pierzga Senior Member

    The water better be very thick, because that boat doesnt look like it will float
  4. bhoult
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    bhoult Junior Member

    Not really sure yet, but I would like to be able to use it offshore eventually.... that would be the target anyway. I think you are right about the hulls, but that is a fairly easy fix. I am also thinking that I should make a T shaped frame to hold the tubing in the form of a daggerboard of sorts on each pontoon.
  5. CatBuilder

    CatBuilder Previous Member

    I like it! I really like the inventive way you took the shipping container, folded it upon itself and made that the deck access. Nice thinking.

    But... like everyone else says, she won't float. Those hulls (PVC Pipes?) Don't have enough volume to hold a carefully cored and light weight carbon fiber structure the size of your shipping container up, never mind one made from steel.

    Do the volume calculation - Archimedes is the go to man. Use fresh water instead of salt water for a margin of error and to ensure you will get enough buoyancy in fresh.

    One other issue might be that the shipping container, being much heavier than the hulls (or outriggers in this case), could make the whole thing just a little bit top heavy, sapping your righting moment.
  6. CatBuilder

    CatBuilder Previous Member

    Oh, one more thing. Those structural beams will be a HUGE pita to maintain over the years. Too many small nooks and crannies to sand, sand blast, weld, paint, etc...
  7. bhoult
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    bhoult Junior Member

    Hmmm... I understand that the pontoons need to be larger. At this stage it is not anywhere near "correct" it was just a way to illustrate the idea. My original thought was that the shipping container would also be partly in the water and would provide additional flotation. That is why I curved the ends up instead of leaving it flat.

    I am getting the impression that everyone that has responded thinks that the container will be suspended above the water. Is there a reason this is necessary other than decreased drag?
  8. CatBuilder

    CatBuilder Previous Member

    Well, the "catamaran" classification you gave it in your first post would be why. A catamaran has 2 hulls.

    If the container is in the water, it's a sort of trimaran, which certainly lessens the size of the amas required (amas on a trimaran with a vaka being the main hull).

    You would also want to add some kind of rounded bottom on that shipping container to handle belly flops and/or to provide some extra buoyancy. A bow would also be nice so when you run into an oncoming wave, you don't just hear a big "BANG!", then find the craft stops instantly. A square bow section would be a very effective brake.

    There is, still, however, much math to be done.
  9. Landlubber
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    Landlubber Senior Member

    ....seriously, are you nuts........look at the complexity of the drawing, think about the material cost and welding, then sandblasting to SA21/2, then the on going maintenance....forget it pal.
  10. bhoult
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    bhoult Junior Member

    Cat Builder, thanks for the clarification, I will start calling it a trimaran. And good point about the rounded bottom. Will have to think of a good way to do that. In one of the other threads they mentioned using cement. Will have to experiment with different materials. Maybe a cement Styrofoam mix.

    Or perhaps add more pvc tubes to the underside. If I use a bunch of small diameter tubes it may accomplish the job.

    Landlubber: Yea. I probably am a little crazy. One thing the drawing fails to convey is that I like building "ugly" stuff. The drawing is actually rather pretty compared to what I have in mind. If it is covered in rust and patches then that would add to the least in my mind.

    I do value practicality and low-maintenance though so if you think it will be a maintenance nightmare even if I don't mind it looking like crap then please let me know what you think the issues will be. I will be using aluminum wherever possible and could replace some of the structural beams with aluminum tubing. Also I was planning to use a sacrificial zinc anode to prevent some of the rust on the iron... the whole boat is metal so conductivity should not be an issue.
  11. CutOnce

    CutOnce Previous Member

    Looks a little .... Waterworld .... and postapocolyptic to me. I'm all for cheap and all for unconventional, but safe boats that last have a pretty much fixed cost per foot, regardless of shape and simplicity of construction. Material standards are there to protect you, not to artificially keep prices high and the activity elitist.

    If you are going to spend the cash to get a 40 foot boat out of the deal, you might as well build a pointy one with a sea-friendly hull shape because it isn't going to cost a lot more than your container in materials.

    If you are willing to compromise on materials, you will have to compromise on safety. If you are willing to compromise on labor cost, just build it where labor is cheaper and save your money by screwing your local economy.

    The boxy shape is not structurally sound, and will require a lot of internal structure to make it strong enough. The cost of this internal re-make of the container will negate any money saved on building this from shipping containers. The things infrequently do float for longer than expected.

    Given the shape of the world economy right now you can buy a used boat, well equipped for less than the labor cost of building this as "new". It's fun to think about stuff like this, but don't let the rosy daydream glow trick you into reaching for your wallet.

    If the world economy crashed, and we were all in survival mode, I might re-consider this project with a less critical eye. Nothing wrong with postapocolyptic designs if we are operating after the apocolypse.

  12. bhoult
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    bhoult Junior Member

    CutOnce: Ah.. you got me there. I am a sucker for the postapocolyptic. I also tend to build stuff just because it is different and I think I can make it work. Probably why I am currently living in a $3000 papercrete geodesic dome as I type this.

    Perhaps it is fortunate then that I can't afford to run off and build stuff as soon as I think about it. 90% of my "big ideas" get forgotten a few months after I get excited about them so I actually have a policy of not spending anything for quite some time. If I forget about it then all is well.

    Problem is I have been thinking about this one for at least 10 years. Not going out to buy stuff but it keeps coming back. If I ever try to build it it will be at least five years from now before I start. So until then I will just keep modifying the computer model and learning how to make it work.

    Thanks for the input.
  13. mcollins07
    Joined: Jan 2006
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    mcollins07 Senior Member

    I've been considering the value of using shipping containers for a cat for a number of years. The containers are relatively inexpensive for the amount of steel. The hull of a cat typically has about a B/L of 1/10 or better. Consider using two containers to make a 80+ foot hull with a 8' beam. An appropriate spacing for the hulls would be about 40', so you could use a couple of 40' containers for the cross beams. You need to cover the containers with foam and glass to smooth the surface out and add thermal insulation. Overall, it could be an inexpensive way to obtain a 100' cat at relatively low cost.

    ~ michael
  14. P Flados
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    P Flados Senior Member

    I do not think long term submergence of any portion of the containers would work well. Think of long term maintainability (paint integrity, structural corrosion, marine growth).

    The big pontoons on the side should probably be big round tubes with any structural stuff insides. This helps with both maintainability and with available flotation.

    All of your other trusses are also better as cylindrical beams.

    By the time you finish all of the above, you will have a not so attractive craft with questionable performance and handling.

    For something this big, building a traditional boat is just way more practical.

    Post 13 above would be for a really big cat that seems to mostly just use the containers for internal structure

    If you want to keep with the "post Apocalypse" approach but go for more functional you could:

    Take 4 containers and lash two end to end for each of two hulls. Then lash them to cross beams with at least a 15' side to side gap between them. Add a rounded nose to each hull. Stretch poly tarp material over the wetted portion to "smooth out" the corrugations and junctions. I am not sure how to seal them up good, but this would be a must. This would give you a catamaran of sorts. Go with an A Frame aft mast with each base attached at the inside edge of the rear containers at the rear cross beam. Keep it "quick breakdown" capable to haul it out of the water one container at a time when not in use.

  15. rwatson
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    rwatson Senior Member

    You are right Flados - its looks great on the computer screen, but its a bag of problems, and will end up costing more over the years than it saves initially.

    A proper, purpose designed steel boat hull would be far cheaper in time and money
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