sea-worthy amphibious craft?

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

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  1. jkittel
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    jkittel Junior Member

    Rather then try to design an unsinkable live-aboard yacht, I have begun to wonder if the ability to go on land may be more valuable then the ability to safely submerge. When rough weather approaches the owner would move on land, going for the highest ground possible before 'laying anchor'. Performing maintenance and repairs to the hull single-handedly would be infinitely easier with the ability to simply drive up onto dry land. Furthermore the vehicle would already possess the means to escape to the sea if it's built as a backyard project.

    However I have not found any existing amphibious craft that appears sea-worthy, and there are also many modes of traction that would allow the yacht to move across the land.

    One method is with low pressure tires which evenly distribute the weight of the vehicle as well as provide buoyancy. This old popular mechanics article describes a cross-county cruise ship. http://blog.modernmechanix.com/2007/08/29/cross-country-cruise-ship/#more-2971

    Treads are another method, and are particularly popular for multi-unit vehicles as one unit can help the other overcome difficult terrain. Of the tracked units I've found, the Arktos seems closest to the sea-worthiness desired. http://www.arktoscraft.com/gallery.htm. The downside of treads is that the buoyancy has to come from the vehicle itself rather then its locomotive units.

    Between treads vs. wheels, which do you think would make more sense? The Arckos design seems better at handling difficult terrain then any vehicle that uses the Rolligon low pressure tires, however tread vehicles are very high maintenance and I would be worried about the long term exposure of the treads to sea water. Most amphibious vehicles are trucks or tanks that double as poor boats, however I am interested in a boat that can handle rough seas and also do a poor imitation of a land vehicle. What hull design do you think would make the most sense? Let’s aim for a maximum width on land of a triple-wide trailer home, or 16 feet.
     

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  2. ted655
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    ted655 Senior Member

    "Between treads vs. wheels, which do you think would make more sense?"
    With treads you'll have fewer water tight seals. Actually there are several already "swamp" exploration & construction equipped amphos. The technology is out there. Most use tracks. Do some more Googling.
    .
    Just how far OUT in a ocean will your contraption cruise. If it can't GET to any land in time, then what???
    .
    Give me a soundly designed & built boat with a sea-anchor! I will hove to & strap myself in my bunk, then tidy up & be on my way.
    .
    What you will have is a collection of anchors just waiting to sink. Good luck but please don't try to cross an ocean in it.
     
  3. kach22i
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    kach22i Architect

  4. Guillermo
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    Guillermo Ingeniero Naval

  5. rwatson
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    rwatson Senior Member

    For an affordable version of amphibious small craft try

    www.sealegs.com

    also Derek Kelsall has dome quite a bit of work on an amphibious catamaran. Try
    http://www.kelsall.com/t1p.html

    I am on your side - I have been tossing around the idea of a self launching small boat for years. The main reason to own a boat is to get to lovely unspoiled places in a bit of comfort - who needs to worry about getting onto that secluded beach on a small dinghy through the surf, and leaving the comforts of home hanging off a bit of string half a mile offshore.

    I hope you come up with something I can afford to buy or build soon.
    Go for it.
     
  6. Hotel Lima
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    Hotel Lima Junior Member

  7. safewalrus
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    safewalrus Ancient Marriner

    Be nice if it could fly too?


    I think your chasing rainbows - like the motor sailer instead of 50-50 tou end up with 40 - 40 or slanted one way or another! Just asking too much! But best of luck in your search!

    the Walrus
     
  8. la cage
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    la cage Junior Member

    Beachable Cataraman

    There was a huge Steel Cat built some years ago in Australia that circumnavigated Aus. Because of his trouble with slipping he built two powered rocker arms inside each hull at the balance point. This enabled him to walk the boat up the beach. In one instance for a longer stay he finished up in a farmers paddock. I like the idea of an ocean going boat that in tidal areas would be beached at high tide, and then raised at one end to level off. After your stay you move out at high tide. Of course it would make more sense if it was built using my method of construction. Cheers from down under. Peter Bourne. www.bourneboats.com.au
     
  9. rwatson
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    rwatson Senior Member

    That big cat sounds feasible - I wonder who the designer was.

    The Sea Lark at Maritime Sales is a good start, but 7.5 knots in light seas, with a 2 metre draught is a bit of a different animal.

    The link provided on You Tube was a great one - can also be found with a bit more info at
    http://www.gizmag.com/go/6906/

    It almost does fly!!!
    A bigger version of this with accomodation and a bit bigger hull for bigger seas would be the go. I'm inspired!!!

    Hey La Cage - you are just up the road from me in Drouin!

    Keep up the good work everyone :)
     
  10. la cage
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    la cage Junior Member

    I think the big steel cat was designed by the builder. He wrote a book about his adventures. Wnston Boord the steel merchant in Warragul was his mate, he would put you right about it. Cheers Peter. wwwbourneboats.
     
  11. rwatson
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    rwatson Senior Member

    Yes I have read that book while waiting to get some steel cut. With a steel catamaran that size, no wonder his best mate was a steel merchant.
    Of all the owner/builder tragedy stories, that was close to the top of the list.
    Warrigal must be the home of home builders. Is "la Cage" insured ?
     
  12. alexlebrit
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    alexlebrit Senior Member

    I love the Fast Track, even got in contact with them about it, but never had a reply. I wonder if they're actually going to do anything with it, or whether it'll just die out.

    One thing I did wonder though, on land the tracks are pushed downwards to provide suspension travel, on water they're lifted up so that the hull provides flotation at start up. I'd have thought once they'd built up speed though it'd be better to push the tracks down and lift the hull completely out of the water.

    Think snowmobile on water and you'll see what I mean.
     
  13. kach22i
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    kach22i Architect

    I don't remember if it's the same company, but the US Military has contracted with some west coast ship builders to develop a LCAC (large hovercraft) replacement which looks very similar.

    I posted it about a year ago. Its a monster of a tracked vehicle.
     
  14. kach22i
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    kach22i Architect

    Found it, T-Craft thread:
    http://www.boatdesign.net/forums/showthread.php?t=16917
     

  15. rwatson
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    rwatson Senior Member

    Had a chat with a company that does re-treads on rubber tracks. Tracks of this size would run to $AU10,000 each - and be at the mercy of ultra-violet, and the cables could be subject to rust from the salwater environment.
    No wonder they spent so much on development.
     
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