sea-worthy amphibious craft?

Discussion in 'Boat Design' started by jkittel, Sep 26, 2007.

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  1. rwatson
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    rwatson Senior Member

    Maybe you could think of monohulls with lots of water ballast - that way you can dump it on landing.

    The wheels and sand problem was one of the reasons that I favoured the 'walking frame' idea I mentioned back in post 26 ( dragline locomotion )

    I was pondering the concept yesterday as I sat on the rocky seashore whacking oysters on the head and devouring them. Rubber tyres and sharp oyster shells would be a problem. They are all over the sandy beaches down here.

    The other night I was watching 'batman returns'. He did a 'revolving car' trick by putting down a big hydraulic 'foot', and lifted and rotated the whole car on it. I gotta have one of those as well.
     
  2. creosote
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    creosote Junior Member

  3. BATAAN
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    BATAAN Senior Member

    DUKW was preferred by southern California coastal survey crews due to its safety in surf. I have seen (and will try to find) a series of photos of one of these ugly floating trucks on a 15 foot breaker, serenely making its way to shore and taking soundings all the way, then drive along the beach, turn and go back out into the surf until outside the breaker line, turn and make soundings a certain distance, turn and surf ashore again, all day long. This was in the 1940s. Nothing else could have done the job and the driver/coxswains were amazed at the ability of the things.
     
  4. kach22i
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    kach22i Architect

    I think it was around 1973 when I was 13 years old that my family took the DUKW/duck ride on lake Michigan and the sand dunes. We went up a river with high cliffs and a few million dollar homes perched above. It was a blast, wish I had some photos.
     
  5. rwatson
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    rwatson Senior Member

  6. BATAAN
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    BATAAN Senior Member

    LARC is the the successor to DUKW and many have been used in tourist businesses around the world. What with the down economy everywhere, not so many people paying for rides in funny floating trucks.
     
  7. thehildi25
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    thehildi25 Junior Member

    Hey guys, Im pretty much new here. I just recently finished my prototype amphibious vehicle. The hull is filled full of foam an the canopy roof is hydraulically operated. Right now I am awaiting a final test with an electric outdrive that I ducted (Kort's Nozzle). A goal of mine would to make this vehicle seaworthy (reproductions), but not necessarily the prototype. Check out the website for pictures.

    www.HCFabrications.webs.com
     
  8. rwatson
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    rwatson Senior Member

    Not exactly seaworthy yet, but a fun start. How did you seal the driveline from water entry ?
     
  9. thehildi25
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    thehildi25 Junior Member

    Hi RWatson, Its a rear engine vehicle based off of the VW chassis. So there isn't a driveline, just a transaxle. Which is encapsulated to the axles of the rear tires. My most current video the one where I drive it into the water gave me an Idea of what I need to take care of and the angle that my craft will sit. I added a lot of displacement since that video and figure to sit even higher. I also made some hydro inserts that could be inserted and attached in the side air intake duct, creating more displacement and directing flow under the vehicle.

    Rob
     
  10. Kaluvic
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    Kaluvic New guy

    I'll jump in here....Ive also been doing some modeling/messing around with this idea.
    Some thoughts....

    The boat would beach stern first so that the bow is always to any surf, that means that the rudders (in my case 2) have to fold up out of the way...something like the way a Hobie's do.

    Tracks would give a greater surface area for "floating" on the wet sand...two track pods (one port and one starboard) would deploy through the hull like aircraft landing gear....these two pods would be located so to carry around 85% of the weight.

    Each pod has a hydraulic drive motor on the pod...this reduces the drive "linkage" to hoses.

    When the tracks are retracted into the hull, the doors are closed and the water evacuated....they don't stay submerged.

    Forward is a single pod with twin wheels side by side...its not steerable but is allowed to rotate like the tail wheel on a tail dragger.

    The boat is a mono...I have two designs...in one, the the tracks deploy from the sides of the bilge keels....

    This boat is quit large....like 20 meters LOA...the idea is to be able to crawl out of the sea and back in again...not necessarily to travel any great distances over land.

    I recognize that this doesn't really meet the inexpensive/retro fit type application that may be the intent of the thread...but it may have some validity.
     
  11. rwatson
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    rwatson Senior Member

    I liked the idea of tracks till I started making inquiries of track makers.

    Tracks can be :-
    Steel - waaaay to heavy and prone to rust out
    Aluminium - dont get made at all, they are not strong enough for day to day use
    Plastic/Rubber Compound - will degrade very quickly in a marine environment. Limited use in freshwater exposure.


    Overall though, the "crawl out", "crawl in" concept would be useful. In a Cyclone Yasi scenario, you could get well above high water.

    Way, way back in the amphbious discussion, there was mention of a large steel catamaran that "walked" up the beach into a field, by having two hydraulic arms mounted each side of the centre of hulls, and simply lifted and pushed its way over the sand. Nice, simple approach - and the hydraulics would be easy to stow.
     
    Last edited: Feb 1, 2011
  12. Tiny Turnip
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    Tiny Turnip Senior Member

  13. Kaluvic
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    Kaluvic New guy

    The tracks would be rubber, I'm not sure why the life span would be shorter than that of a tire or the tube on a shaft log?
    I've had tracks on a Jeep that I've used all seasons for about 5 years and also on a couple quads...I'm very impressed with their resilience.
    The jeep tracks have carbon fiber rods that run from side to side "cast" in to the construction of the track...I believe this is to give stiffness in that direction.
    The tracks I propose for the boat, would not be the same shape as what I've got on these vehicles....more like a lower profile version of these http://www.landluvr.com/models.htm with drive capacity....(these are pull behind)
    Being able to get out when bad weather is coming would be great...but I'm think-in it would be used way more often for more mundane reasons...like destination planing may look very different if you no longer have to worry about a safe anchorage.

    Tiny Turnup...pretty cool video....thanks.
     

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  14. rwatson
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    rwatson Senior Member

    The are *exactly* the gear that I spoke to the local rep about. They were sending a shipment to Antarctica at the time. Not only did he say the rubber couldnt be guaranteed in a marine environment, but the three-wheel attachment would also not be suitable.

    Considering that the cost was well of $aus12,000, I wasnt happy to take the risk.

    I am guessing that sun,sand and salt water are a far more toxic combination than snow and fresh water environment. I would love to hear differently.
     

  15. Kaluvic
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    Kaluvic New guy

    Could be...I haven't exposed them to sea water.
    I'm not really figuring on buying off the shelf...its probably all custom.
    There seem to be folks out there with the expertise that you can work with.
     
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