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

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

  1. kach22i
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    kach22i Architect

    submerged logs + hydrofoil = bad experience

    I like the cat being drawn up, it seems to follow the KISS method.
     
  2. SKot
    Joined: Jul 2010
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    SKot S Kot

    I prefer surface piercing hydrofoil becouse has few advantages, most important strenght.
    Albert Einstein's maxim that "everything should be made as simple as possible, but no simpler"
    Idea fly low and slow is for me the best way for economical sufficiency.
    kach22i tell me please something about hovercrafts. How many HP I need for hovercract flying?
     
  3. congoriver
    Joined: Jun 2007
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    congoriver Junior Member

    Skot, I'm not sure, but we're talking about a cargo vessel of some sorts. Aren't hydrofoils supposed to be "flying" through the water?

    It's not like we need *that* much more speed. We should just have something that beats the small pirogues and the huge barges that currently do this trajectory.

    Remember, the goal is to do 500km (say 300 miles) in about 2 days, on a broad, deep river that flows at a speed of say 3 knots.

    Maybe, like Kach22i says, we should keep it simple. The catamaran is already a complication compared to a long, slim pirogue.
     
  4. SKot
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    SKot S Kot

    Give me a litle time, I will calculate something and compare fuel consumption for the same hull (the same wight and lenght) in displacement mode (slow), planing mode and flying mode on the same way.
    I remember, our goal is most economical cargo not speed.
    As simple as is possible.
    Everybody since first hydrofoils looking for speed with hydrofoils.
    Peoples likes speed. Speed is not so important in our case of most economical river cargo.
    I am looking for inversly way
    less drag = less power = less fuel consumption

    Secund advantage, if you fly by wings, just wings are little comlicated.
    hull can be everything.

    This is very interesting buisness. I would like to have river with golden leafs like you.
     
  5. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    My original proposal assumed an all up weight of 15 short tons, gross (full of fuel up river and slightly more than half full down river, laden with leaves) and a power requirement of 10 hp per ton. Therefore, you will need about 150 hp. You may get away with less than that, but we are talking 15 kts here, Your average speed might be less than that as you deal with large barge and small boat traffic, as well as darkness and bad weather. The higher speed also tends to discourage pirates.

    If high quality (straight grained, rot resistant) wood is available, lap streak planking would probably be the best to make the hulls as you are getting the best strength to weight ratio without going to expensive epoxies. Most of a hull's strength comes from its surface construction.
     
  6. bearflag
    Joined: May 2010
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    bearflag Inventor/Fabricator

    Do we even know how many "tons" of leaves the market will bear?

    I imagine there may not even be enough leaves to even get 15 tons every few days. Maybe not even one.

    Something to consider.
     
  7. congoriver
    Joined: Jun 2007
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    congoriver Junior Member

    Well, the market is actually unknown, in the sense that the number of collectors is potentially huge, and in the sense that a small decrease in price of the leaves in the capital might prompt a much higher consumption.

    But I think if there was really a bigger market than today, more cargo planes would be doing this trade.

    Let me check the daily consumption of fumbwa in Kinshasa today.

    I have the feeling than an extra supply of 15 tons a week is a lot, and might actually lower prices considerably. Let me read that report again.
     
  8. bearflag
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    bearflag Inventor/Fabricator

    Probably smart to have a few backup/additional/supplementary cargoes. You never know if big-bad government, mafias, competitors, weather, water shortages, etc.

    Would be a shame to build a boat and have no leaves.

    As a plus side the catamaran gives you lots of options. All else fails you could use it for fishing, or transportation of anything else.

    You should be thinking, how can i guarantee my supply? what other crops are there? how do I get the crops to my boat? what other things can I transport? etc.
     
  9. SKot
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    SKot S Kot

    Let’s take 14,5m (47,57 ft) lenght Hull.
    Weight of hull is 7000 kg for hydrofoil and 4000 kg for displacement hull. (multihull or monohull)
    We can take 7000 kg of leafs with hydrofoil and 10000 kg with displacement hull.

    Distance is 500 km
    Cruising speed is 20 kts for hydrofoil
    And 7 kts for displacement boat (most efficient speed for displacement mode for this lenght of boat)

    Cruising time of 500 km will be 13,5 hours for hydrofoil and 38,5 hours for displacement hull. (without breaks)

    Power you need: 35 SHP for hydrofoil and 30 Shaft horsre power SHP for displacement 47,5 ft hull with cargo for most efficient speed for this boat.
    (for hydrofoil you need additional engine for take off for short time)

    Fuel consumption 102 liters for hydrofoil and 250 liters for displacement hull. (one way)

    Multihul has better initial stability than monohull vessel and has better length displacement ratio

    Price for river cargo is 8,78 FC/kg for hydrofoil (one way) and 15 FC/kg for displacement vessel (one way).
    This is very very good buisness
     
  10. hoytedow
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    hoytedow Wood Butcher

    Agreed.
     
  11. pedalingbiped
    Joined: Jun 2010
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    pedalingbiped Junior Member

    Hydrofoil is more complicated to manufacture.
    The foils are actually airplane wings

    The foils in the book I linked to before are NACA 63-412 and NACA 4412.
    A much simpler foil is the Ogival. Take a piece of pipe, cut 1/5 lengthwise and weld a flat plate to the bottom. It only has 1/3 the lift of the better foils but is simpler to make.

    I still recommend looking into hover craft which go the same speed as a hydrofoil but are simpler to make.

    My alternative preference is like those above, either a cat or single displacement of around 30 meters.

    Remember, the goal isn't to get rich, it is to develop a business that can be copied by more people to bootstrap their economy so more people have more money to start more business.

    From my understanding, Congo Republic is just now over coming a civil war where fighting was over resources. The economy and infrastructure are in shreds. Over 3 million were killed in this war.
    http://news.bbc.co.uk/2/hi/africa/country_profiles/1076399.stm

    The idea to harvest leaves is just the start.
    Let's help congoriver to manufacture a boat that can be copied by anyone.

    Taking fuel upriver is profitable. He can also find markets where the farmers want to buy things from him with the money they make selling leaves to him.
    The boat would need a large enough crew for security.

    If the price of leaves drop then other commodities can be brought to the capitol.

    I think this idea could be expanded to provide all the major cities with commodities within 500km of them.
    The River is 2900 miles long with other major rivers feeding into it.
     
  12. congoriver
    Joined: Jun 2007
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    congoriver Junior Member

    Below, in the picture, some other interesting products that might be transported in case there's a problem with the leaves. (Prices in that spreadsheet fragment are in US$. "Difference" is the difference between the price in Mbandaka and that in Kinshasa).

    Some very interesting crops, with a huge potential profit margin... These margins for socalled "non-timber forest products" are much higher than those found in either cash-crops or subsistence crops (corn, cassava).

    Unfortunately, I don't have any data on the current consumption levels of these different NTFP crops. This will require some research in the field.
     

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  13. SKot
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    SKot S Kot

     
  14. ancient kayaker
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    ancient kayaker aka Terry Haines

    500 km in 72 hours or less doesn't sound very fast. If the river is navigable by large boats, why are you discussing hovercraft and such?
     

  15. kerosene
    Joined: Jul 2006
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    Location: finland

    kerosene Senior Member

    I have to agree with ancient kayaker.
    Even if you count 12h/day (minimal dark riding) it comes to 14kph = 8 knots.

    Which doesn't seem unachievable for a long slim mono or cat.
     
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