A better idea for Congo - a speedy tug and a plastic bag

Discussion in 'Boat Design' started by congoriver, Jul 14, 2010.

  1. SKot
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    SKot S Kot

    For minimum fuel consumption, not for speed
    We have no friction and weave resistance if we flying by hovercraft, hydrofoils or another gizmos, but this ideas are to much complicated.

    less fuel consumption - bigger range and more cargo.

    I don't know yet, but monohull has to big wetted surface. I calculate this at this moment.

    I think catamaran with big cargo platform will be cheaper than big monohull and more efficient.
     
  2. kach22i
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    kach22i Architect

  3. bearflag
    Joined: May 2010
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    bearflag Inventor/Fabricator


    This is why I proposed it in the first place :) (may also have something to do with me currently designing a 60 foot cat [cruising not cargo])

    There are other solutions, but they are all a bit more capital intensive and pie-in-the-sky. Its better to build something soon, and get the business started, franchise it, and once you have the capital think of how to improve it.
     
  4. pedalingbiped
    Joined: Jun 2010
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    pedalingbiped Junior Member

    The reason I choose Hovercraft is it can go 100kph. So a 500km trip is done in 5 hours. Round trip is 10hrs.

    I am also looking toward the future. The infrastructure is torn up because of the civil war. Also, there are thieves running around. Our State Dept says bandits are robbing travelers on roads and trains and recommends that its citizens use neither.

    So it looks like the river is going to be the major highway for the near future.
    The capitol has a population of 8 million. I think that a small percentage has the money to spend on travel if it is convenient and safe. They also don't want to spend time on a floating village with the unwashed masses.

    The reason there is such a price difference between 2 cities only 300 miles apart is because goods can not travel on the roads, if even a road exist. The Congolese have always used the River as their hiway.

    The biggest hovercraft on hovercraft.com uses a v8 engine to haul 12 to 16 people or 2500 lbs. A metric tonne = 2204lbs

    Brazzaville is a capitol city just across the river from Kinshasa

    I am also of the opinion that a larger boat of 30 to 40 meters is needed. A boat that can be copied so any one can build or get a hold of one.
    Also, I believe congoriver should concentrate on products that can be exported. Every developing country is short on foreign currency.
    Also a boat big enough to support a crew of 3 or 4 for safety.

    Once wants and needs are taken care of at the capitol, then it would be time to expand the boat program to other major cities. With the Congo river being 2900 miles long and then adding up the major rivers that drain into it ( I haven't counted) I would estimate there is 5000 miles accessible by boat.

    Wikipedia states that there used to be steamers on the river. Modern steam engines are available, they just need a boiler to feed them steam. Of course congoriver would have to import them.

    I believe that with increasing trade on the river safety will increase as more have-nots start being have's.

    Congoriver has his work cut out for him.

    I attached a spread sheet based on congorivers list of prices. Total profit is based on a payload of 10 tonnes (1 tonne = 1000kg = 2404lbs)
     

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  5. kach22i
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    kach22i Architect

  6. SKot
    Joined: Jul 2010
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    SKot S Kot

    Low tech solution with high tech aspiration.
    This is my drafts of boat for Congoriver (under construction)
    Very light and durable.
    Easy to made with simple tools.
    Wight od this trimaran is about 3,5 tones with full fuel.
    Wight with cargo about 20 tones with 80cm draft.

    16,5 tones maximum cargo

    Very easy construction, Every you need is time, wood.
    Superstructure is wooden.
    Hull for first layer resin impregnated canvas, next simple GRP without mold, immediatelly laminated on the first canvas layer.

    This construction is litlle similar to birch bark canoe or innuits skin boat.

    Empty trimaran can easy to reach planning speed with good efficiency.

    Next step - hydrofil wings addition

    Enigine 40 - 50 HP inboard diesel engine
    Propeller 22 inches 3 bladed 50% DOR P/D ratio 0.7 - 0.8
    LOA 14 meters

    Cargo platform 10 x 10 meters.
    Bag capacity on the picture about 3,5 cubic meters (for understand scale)

    This man in blue on picture 1,95m tall (the same me :))
     

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  7. bearflag
    Joined: May 2010
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    bearflag Inventor/Fabricator


    Interesting... Though since it is "doubtful" that you would want to fly one hull, is there any advantage to a trimaran for this application?

    You would think that making 2 hulls would be simpler, and have less wetted area, etc for same functionality (in this case).

    I suppose... single inboard engine or something? instead of 2 for a cat? Could just run a car engine on the crossmembers too like you see on the small river boats in thailand etc.


    EDIT: Also I would add length... and narrow the hulls. Keep the same appx. capacity. That way you would have better/more efficient speed curve.
     
    Last edited: Jul 22, 2010
  8. SKot
    Joined: Jul 2010
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    SKot S Kot

    If you want have the same displacement, wetted surface is bigger for catamaran in this case, I calculated it.
    Catamaran with 100 square meters cargo platform, has insufficient strenght and to small displacement.

    We need one more support for our platform bridge

    We need multihull for maximum strenght and minimum wetted surface and mass of our vessel

    We will go about 6,5 to 7 kts with cargo in displacement mode of course, very simple.

    Without cargo we can to go in planning mode.

    I said: calculating wings will be in next step....... soon :)
     
  9. kach22i
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    kach22i Architect

    I guess speed will not be protecting you from pirates.

    Better add some gun turrets too.:cool:

    It's looking good all joking aside.:)
     
  10. bearflag
    Joined: May 2010
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    bearflag Inventor/Fabricator

    Surface piercing daggerboard type foils (if any at all) might be preferable.

    Easier to make, if you hit a log they can just break off and you can motor without them. Easily repaired/replaced.

    Additionally you could raise them for shore loading, low water, or hazards like sand bars, fishing nets, river debris, etc.
     
  11. pedalingbiped
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    pedalingbiped Junior Member

    An inverted t foil on the front of both outriggers would get the bow up and might be enough to plane when full loaded. 4 inch wide foils can lift 300 - 500 lbs each, depending on width. Another type would be ladder foils. As you gain speed each foil has more lift. The faster you go each "rung" climbs above the water reducing lift area. Self regulating. They can be bolted so you can lift them forward and up to raise them.

    With foils, square the speed, cubed the power...
    If speed is 10kts with 10 hp then 20kts would need 100 hp

    At 16.5 tonnes, with a density of 500 kg/meter3, you would only need 32 meter square
    A ball park figure of profit would be 13,000 to 33,000
    13,000 will buy you 43 liters of fuel. 11.5 km/liter
     
  12. liki
    Joined: Nov 2008
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    liki Senior Member

    If there are gangs of armed bandits roaming around, I reckon that they would find a fast hovercraft all too beneficial for their purposes and would readily kill just for the craft itself. And government officials could the next in line to confiscate the craft.

    And if you start to make money big time, it seems likely that you will end up paying some "unofficial taxes" for the bandits and/or the officials.
     
  13. bearflag
    Joined: May 2010
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    bearflag Inventor/Fabricator

    Make your boat look as "home-made" as possible do all your banking electronically, carry no cash. Bandits wont want your leaves.
     
  14. SKot
    Joined: Jul 2010
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    SKot S Kot

    You right, but If you increase speed from 10 kts to 20 kts you increase this speed double.
    2 x 10 =20
    this means drag will be increase 2^2=4 power 2^3=8
    You need 80HP not 100HP.
    Remember flying by foils is generating 10 times less drag than the same boat in plannig speed mode. Upper side of wing generate 2/3 part of lift.

    We must fly as slow as possible.
    Fly low and slow.

    Density of leafs is 150 - 250 kg/m3 not 500 kg/m3
     

  15. TeddyDiver
    Joined: Dec 2007
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    TeddyDiver Gollywobbler

    No fence.. but too complicated thoughts for a rainforest.. Think about something you can repair and maintain with a hand saw, ax and monkey wrench ;)
     
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