Big houseboat ?

Discussion in 'Boat Design' started by parkland, Oct 19, 2012.

  1. parkland
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    parkland Senior Member

    As some of you know, I have been thinking of building a trailer-able folding houseboat.
    We were also looking at some vacation property for sale.
    I am now contemplating just going for a bigger boat that is big enough to live on in the summer. (And leaving it sit there, not trailering it anywhere.)

    So.. I'm looking at 48" x 60 ft pontoons.
    They can hold about 40,000 lbs at 50% submerged.
    Is there any reason a person would NOT want to use pontoons for a houseboat like this size?
    This is for fresh water, So I'm assuming the aluminum should last darn near "forever".
     
  2. parkland
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    parkland Senior Member

    I should specify that I'm just wondering about how long the pontoons will last...
     
  3. PAR
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    PAR Yacht Designer/Builder

    I'm not sure why you have a fascination with pontoons, as these are the worst approaches to supporting a house (or boat). Material durability is directly related to maintenance, regardless of choices.
     
  4. parkland
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    parkland Senior Member

    My "Fascination" is that you can buy the pontoons and frame as a kit, and it's transportable. And Coast guard canada approved.

    Why would they be the worst approach to supporting a houseboat?
    (I thought lots of houseboats had toons? Are these considered "throwaway"?)

    48" x 60 ft pontoons are 30,000$ to 50,000$ for a set.
    Do you have any better ideas?
     
  5. parkland
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    parkland Senior Member

    One place just got back to me with a quote 20,000$ less than another place for the exact same thing!

    Is this normal, or should I consider it a red flag ?

    29,100$ for a set of 48" x 60 ft toons.
    5700 lbs
    Includes shipping.
     
  6. WestVanHan
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    WestVanHan Not a Senior Member

    I'm originally from the lake where houeboats are very popular...I'm sure you know the one.

    50' houseboats maybe 10-15 years old in good shape run $25-40k.

    Am off fishing all weekend, use kijiji or craigs or google.
     
  7. Ike
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    Ike Senior Member

    Red flag? more like a red flashing strobe light? What aluminum alloy are they made of? There are all kinds of aluminum alloys but only ones in the 5000 and 6000 series are suitable for marine use.

    Frankly I would not go for pontoons on that large a houseboat. I would want something under me that would support a lot more weight than two pontoons. A houseboat that big is going to have a big superstructure and a lot of appliances and furniture in it. You need all of the displacement you can get at that size and pontoons limit the amount of displacement. especially if you start loading them down.
     
  8. parkland
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    parkland Senior Member

    I do know which one you speak of haha.
    In fact I just found one for sale for 10,000$.

    There are a few things with those boats, that I don't like, though.

    -Waterslides
    -2 stroke outboards
    -Transport costs
    -Unknown history

    Of course the price is awesome....
     
  9. parkland
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    parkland Senior Member

    Were talking about 2x 48" pontoons, or 3x42" pontoons... (60 ft)

    Should be able to hold up a MINIMUM of 40,000 lbs.

    That exceeds by far anything I can imagine putting on the deck.
     
  10. parkland
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    parkland Senior Member

    5052-H32

    3/16"
     

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  11. philSweet
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    philSweet Senior Member

    You need some weight in the hull for one of these things unless you are in a very protected place. Usually the powertrain, tankage, and genset will all be down in the hull on a boat this size. The pontoons are 100% wasted. That is all living and equipment space you can't use. At fifty foot or so, the hulls of a catamaran are fully used for living and equipment. Pontoons have no shape to them and are not efficient moving through the water at any speeds much above a crawl. And unless you are quite careful with the design and get a bit lucky as well, they won't have less wetted surface than a monohull with similar stability. They will need to be carefully designed to support a haulout. The bigger the tube diameter, the bigger the trouble this is.

    As much as I hate to say this, I think you should go look at some big Gibsons. They do have the General Arrangements pretty well nailed down.
     
  12. parkland
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    parkland Senior Member

    I did look at the gibsons design, I think they are meant for big open water.
    What do you mean about "the bigger the diameter, the more trouble"?
    And what do you mean by "haulout"


    I am talking a bit with one of the pontoon boat companies, and we were talking about 3 pontoons, 48" x 70 ft.
    The deck would be 22' wide, so there would be lots of room under the floor for water, sewage, equipment, engines, etc.
    A good amount of weight would be very low indeed.
    It seems to be working out better than I hoped.
     
  13. parkland
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    parkland Senior Member

    And sorry, also I forgot to say that the waves on the lake I want to use are not ocean type waves, and there is lots of bays to hide in lol.
     
  14. parkland
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    parkland Senior Member

    22' wide - 3 x 42" pontoons = 11.5 ' of empty room,
    or 5.75 feet on each side of the middle pontoon.
    If the deck sits 12" off the pontoons, that leaves a TON of room for water and sewage tanks.

    I know I still want to do engine pods like my old idea; a bin that the engine sits in, and sits barely above the water line, and the prop shaft exits on an angle down into the water.
    So the engines weight will sit almost between the toons more than on top of them.
    I imagine if I can get sewage, water, and fuel all under the floor, between the toons, there is really not much more a person could do.

    That is already much better that off the shelf pontoon houseboats.
     

  15. parkland
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    parkland Senior Member

    Here is just roughly what I was thinking of doing,
    And shows the "motor pods."
    All the tanks and stuff, would hopefully find spots under the floor, in between the pontoons, keeping a low center of gravity.

    There could even be a floor under them, but not s rigid floor, just something strong enough to hold up insulation.
    Corrugated metal roofing comes to mind.

    And the motor pods.... they would be metal bins, large enough to hold an inline 6 diesel, and marine transmission. The prop shaft would extend behind them 20 ft or 30 ft whatever. The pods and shafts would tilt down to immerse the propeller and rudder assemblies into the water.

    The pods would also allow engine removal from underneath, by removing a few retaining bolts and lowering the engine pod assembly onto or into something.
    This would be awesome, because it allows the use of inboard engine components, without the risks associated with them.

    Also how awesome would it be to remove an entire engine and prop assembly out of the boat with only a few bolts if needed?

    I like it.
     

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