brainstorming for a 'micro' 2TEU container/2x vehicle RORO cargo haul

Discussion in 'Boat Design' started by big_dreamin, Oct 20, 2016.

  1. big_dreamin
    Joined: Jan 2014
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    big_dreamin Junior Member

    This is totally unrelated to my other threads here btw so please don't assume it's the same thing in a different way. :)


    I found myself brainstorming on the usefulness and needs of a boat for smaller scale delivery to unimproved or "off the beaten path" conditions (like beaches without even docks there yet) and wanted to carry the idea a little further...

    The specific desire is the ability to deliver one FULL Sealand ISO container up any random unimproved beach without a dock. (not necessarily to extreme weights/not talking cubic concrete here, but with 5 tons tare weight lets assume at least 5 tons and preferably more cargo) And to also be capable of delivering one longer vehicle or two shorter vehicles (ie common cars/light trucks) with the same boat.

    It's possible this may not be financially worthwhile or feasible, or 'works better scaled up' economically, but I figure i'd start at the smallest building block I can think of - basically a 2TEU container ship. That could also haul a couple of light trucks, or something like a school bus. (and obviously things like smaller farm tractors, construction equipment sized to fit on a standard semi flatbed, and similar)

    Possible additional or separate brainstorming concerning a way to deliver to the beach without a permanent unloading dock! Would it be best to use some kind of landing craft, some kind of modular ship construction combining the landing craft with the boat, or attempting a very shallow draft that maybe could even be beached so that it's more feasible that some kind of unloading rails or steel grates on floats like a floating bridge could be pulled up for an impromptu unloading dock ahead of the boat, or something similar. (like beach it within 80 feet of dry beach as the tide is going out and bring with 80 feet of steel grating to let you drive vehicles out, or allow to be towed out the container if its placed on something with wheels)


    If YOU were trying to do the same thing how would you do it? Convert an existing vessel? Custom make a new vessel? Would the weight require a monohull/would a cat have to be extremely wide to be stable on the seas with weight above deck?

    This is a pretty open brainstorm just because i'm curious whats out there. I'm sure normal commercial hauling would involve ungodly expensive helicopter lifts from an offshore vessel of some sort and i'm wondering if there's something that could bring a delivery cost for a container or couple vehicles down into the thousands instead of what I imagine would be tens of thousands of dollars if going to an out of the way place.

    I have a number of ideas which become feasible if the cost of delivery can be lowered enough but i'm not even sure how such a problem is handled now. (or if it really even is)
     
  2. CatrigCat
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    CatrigCat Junior Member

  3. cesmith9999
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    cesmith9999 New Member

  4. sharpii2
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    sharpii2 Senior Member

    If we're talking about off loading only vehicles, wouldn't it be a good idea to forget the container? It adds 5t of mostly useless weight. And it's bulky and difficult to move, without gantry cranes, as well.

    The landing craft concept for this kind of work is difficult to improve on, because the weight of the cargo can be kept low and very close to the design WL. A catamaran will require the cargo to be kept higher and will probably need a longer ramp.

    There are problems with the land craft model too. One is the slope of the beach. If the slope is too gentle, it becomes difficult or impossible to get the landing craft close enough. Then you need an amphibious craft, which can crawl out of the water, up to dry land. It doesn't necessarily have to crawl all that well, but just adequately.

    But this assumes a beach with hard sand. What about a more mucky one?

    The biggest problem with all of this is that this vessel will have to be quite complicated, and probably not all that efficient, when it comes to vessel weight divide by cargo weight.

    There is a good reason why people go to the trouble of building expensive docks and wharfs.

    During the D-Day invasion, a floating artificial harbor was towed across the channel, following the invaders.

    Once the enemy was pushed far enough from the beach, the artificial harbor was set up, so the heavy artillery, tanks, and trucks, not to mention even greater magnitudes of troops, could be more quickly off loaded.

    Now that I think about it, a special catamaran might just work.

    It would be an extremely unusual one.

    Its cross beams would be under water, attached to the bottom of the hulls.

    The reason for this is that it will have a floating platform which will serve as its bridge deck. This floating platform will carry the cargo.

    It will be winched up to deck level for when the vessel is under way, so it will not pound in a seaway.

    Once it's at the landing area, this catamaran will come as close to the shore as possible, without running aground.

    Then the floating platform will be lowered. It will have its own propulsion.

    Once it runs aground, a crew will go ashore with a sturdy anchor and plant that anchor firmly into the ground. A winch, on the platform, will then drag the platform out of the water.

    Once its cargo is off loaded, the same winch will then drag the platform back into the water, using the anchored catamaran as a bollard.

    This scheme works so good in my mind, I find it troubling to pick apart its flaws.

    The biggest of which is its dependence on absolutely calm conditions. Any kind of seaway would make this operation very dangerous, if not impossible.

    Also, there is the great weight of the catamaran, the floating platform, and the equipment needed to make it all work:

    Two heavy anchors,
    At least two engines, one for the catamaran and one for the platform,
    Two very sturdy powerful winches, one for the catamaran, to winch the platform up to deck level, and one for the platform itself, to winch it ashore, then back to the catamaran,
    not to mention the catamaran itself, which needs to be sturdy enough to be not only sufficiently seaworthy, but sturdy enough to take all the loads imposed on it.

    The same goes for the floating platform itself.

    The very realistic prospect is for this vessel to weigh four times as much as its would be cargo.

    I hope you see that it is almost impossible to design such a vessel which will work with any beach it encounters.

    For some beaches (ones with hard sand, sufficient slope, and maybe some surf) the mono landing craft model will be best.

    But for muddy, shallow beaches (but with no surf) this complicated catamaran model will work.
     
  5. CatrigCat
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    CatrigCat Junior Member

    Delivering goods to a beach is both time consuming and expensive.

    Weather is a bigger problem. If the ship arrives on a windy day to a lee shore, goods cannot be unloaded. The ship may have to wait for days or leave, not delivering.
     
  6. big_dreamin
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    big_dreamin Junior Member

    Well I guess one possible design I have in my head is just what I remember from Saving Private Ryan when they were dumping troops onto the beach... basically a big box, forward opening with a ramp once you get it far enough up the beach. Just capable of heavier weight.

    I'm aware there are things which can do the job like hovercraft, but i'm trying to think of lower budget ways. (not cheap, I don't ever expect this to be cheap, just trying to bring out the cleverness)

    The idea I guess swirling around in my mind is that not everywhere has 'proper' dock access, so maybe some money could be made with cargo delivery to underserved areas. (which are often also poorer so there's reduced interest, and not enough profit to interest the 'big' boys, but if you can figure out a cut-rate way to do it, being places all along africa potentially or other coastal areas with crappier port facilities)

    The personal side of the thinking is that if I ever buy myself a little piece of paradise on the beach it will probably only be remotely affordable because its waaaay off the beaten path. So there wont be any dock, no nearby roads, and it'll be "figure it out yourself" for delivering stuff.


    Yes but they also make nice building blocks for rapid construction too once empty. And they are practically a "waste product" in many areas not worth the money to ship back when there is a major port nearby, some can resell them for like use as storage. The personal use might be drag it up the beach and use it as a building block for housing while also having the stuff inside it.

    That being said it may often be worth emptying the container entirely to load up the cargo hold so that a lighter 'landing' vehicle can haul it to land. But I figure i'd see if a Plan A of moving a container at a time is even feasible.


    One idea I currently have in my head is basically a trimaran with a wider central hull. (not necessarily an ILAN though) Design it so the central hull can have the two vehicles or sealand container within it so it's low and that the buoyancy of the central hull itself floats that weight.

    The outer cat hulls both stabilize and hold the 'normal' weight of the bridgedeck, fuel, and such. Ie dont have to be overbuilt like it would to handle a full container on top, just strong enough that the extra buoyancy from the central hull 'lifting' the cat is not a problem. Make the central hull actually variable draft - kind of a jacking system that raises or lowers (relative to the outer hulls) based on how much weight is in the center to that it's not designed for say 33 ton buoyancy with a 10 ton load pushing up on the bridgedeck. Make displacement equal weight.

    Then make that central hull DETACHABLE/that's basically your landing craft of sorts. The cat hull still floats on it's own since it's designed to - the central hull floats like a monohull (or maybe has some smaller ILAN like stabilizers attached) and is designed to be beached then open it's front. I suppose the central hull could even be made amphibious or that it converts to it after the ocean trip.

    Yes there is still all the PITA of moving the container further up the beach and such but that remains within the normal types of rigging, rollers, blocks'n'tackle, and other stuff that farmers and others routinely do without cranes already. I'm just trying to figure out getting it from boat to beach first.

    PS thanks for the long brainstorm and interesting commentary. Do you think my trimaran idea improves on any part of that?

    I don't think I would need access to all kinds of possible beaches - just many which are not properly served already. (where both coastal land is cheaper/ie for my retirement getaway, and also there's the possibilty to haul cargo for others/making decent side money due to lack of infrastructure)
     
  7. mydauphin
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    mydauphin Senior Member

    People have using landing craft type vessels for delivery to small island since ww2. They are still being used. They fit a crane on then and can deliver several different ways. Here is the problem, there size makes their use relatively expensive. The cost vs cargo equation makes then expensive. So they are only used for special cases.
     
  8. timesup_tim
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    timesup_tim New Member


  9. gonzo
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    gonzo Senior Member

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