Designing and building a houseboat

Discussion in 'Boat Design' started by JohnMarc, Mar 13, 2018.

  1. jorgepease
    Joined: Feb 2012
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    Location: Florida

    jorgepease Senior Member

    Then you can get away with low clearance but right on the waterline and you will regret it, that is going to be a first class noise maker even with ripples. Raise the deck 12 inches and you are good to go, 7 foot headroom is plenty in a boat.
     
  2. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Metrics is rigged out so 1 cubic meter displaces 1 (metric?) ton of water. So if you had a 1 cubic meter box and put 1 ton of weight in it, the top would be level with the water. You want reserve buoyancy, so in practice you would basically only load the box with 1/2 ton of weight which would leave the box submerged halfway. So, if you want to carry a total load of 8 tons ( which would be the boat itself plus all equipment, fuel, people, food and beer), you design buoyancy enough for 16 tons.
     
  3. JohnMarc
    Joined: Feb 2018
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    Location: Knysna South Africa

    JohnMarc <--- My ultimate goal

    I feel embarrassed for my previous statement, yes of course that would be level.....thanks for that.....
     
  4. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    If the other side of the bridge is where you want to get, it seems to me getting under the bridge is what you design for.

    You say 2.5 meters is the clearance at low tide. You have a 6-7 ft tide there so your window of opportunity to get under it will be somewhat narrow. Tide depths change with different moons, seasons, weather etc., so is 2.5 clearance at the lowest of the low tides or the highest of the low tides or is that an "average" low tide?

    Tides shift timing everyday, around here about an hour, so everyday the low tide is (for example) an hour later. One day it may be low at 8AM and 8PM and a week or so later it will be 2AM and 2PM.

    If you are limited to a short window of time to get under it going one way, you'll have to wait about x amount of hours to get back out.

    For a given boat, the deeper your boat sits in the water the more clearance under the bridge you have and the larger the time frame for getting under. If your boat sits on top of the water you have 2.5 meters to play with, if your boat is submerged 1 meter, you have 3.5 meters to play with.

    For a given weight, the smaller the size of the boat, the deeper it will set.
     
  5. SamSam
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    Location: Coastal Georgia

    SamSam Senior Member

    Am I correct in saying you have waves of no more than 4 inches and the wind is just an occasional factor? If so, I wouldn't design for the wind or the waves. Maneuverability in currents would be a major factor and I'm not so sure pontoony/catamaranny hulls are especially maneuverable.
     
  6. JohnMarc
    Joined: Feb 2018
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    Likes: 3, Points: 8
    Location: Knysna South Africa

    JohnMarc <--- My ultimate goal

    y
    You are quite right in that, wind driven waves of no more than 4 to 6 inches.....
    Coming to your point of the larger the boat the higher it would sit in the water, if I have a 3,5 metre x 14 metre x 900 mm Hull then it would need upwards of 24 tons to create a draft of 500 mm i.e. my clearance under the bridge would be 2.9metre....am I wrong in thinking this, as said earlier this is early days in the design just estimating the numbers ...
     
  7. jorgepease
    Joined: Feb 2012
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    Location: Florida

    jorgepease Senior Member

    Here is an idea, make yourself a regular cat hull/pontoons with water bladders/tanks that you can fill to sink or raise the boat for bridge crossings. Put a motor on each hull to maneuver in heavy tide, wind or tight spaces.
     
  8. JohnMarc
    Joined: Feb 2018
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    Location: Knysna South Africa

    JohnMarc <--- My ultimate goal

    With the design coming along my thoughts are now going towards the wood. I have read up quite a bit on the different types of timber that is suitable for boatbuilding but what these sites don't detail is what type of wood is best suited to the different elements of the boat (i.e the Battens the Chines Deck Beams etc and of course the ply or planking) I seem to have quite a variety of exotic and local woods available. I wonder if anyone can shed some light on this subject for me.
     

  9. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Here's a different concept, it's like a duck and her baby duckinos...
    [​IMG]
    Peacock Bass Floating Bungalow Camp - Boats and Guides http://www.acuteangling.com/peacock-bass-trips/floating-bungalow-camp/boats-guides.html

    Or you could have a pushboat and a barge thing, where you'd have an unpowered barge-ish/houseboat type thing and then push or pull it around with a regular boat. That would let you moor the houseboat and then use the motorboat to explore, go to the store etc and then have it for everyday use back at the island house.
     
    jorgepease likes this.
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