Trimaran motorboat / stabilized monohull

Discussion in 'Boat Design' started by Eric DEBORDE, Oct 12, 2009.

  1. HJS
    Joined: Nov 2008
    Posts: 332
    Likes: 44, Points: 28, Legacy Rep: 288
    Location: 59 45 51 N 019 02 15 E

    HJS Member

    Transport Efficiency

    Refering to my expierience with ZEB 25
    it is important to locate the sponsons in the right posisition
    and to choose the right bottom beam
    before we made up the final design we made many test
    the position of the sponsons is very critical
    it is hard to calculate this
    practical test is the best way

    ZEB 25 is designed to FnV 2.0
    so at higher speed it can be better than showed in the chart


    in the chart your boat are the yellow dots
    your boat shold only need 36 hp if properly designed


    js

    www.sassdesign.net
    www.zeroemissionboats.se
     

    Attached Files:

  2. mwatts
    Joined: Jul 2009
    Posts: 66
    Likes: 1, Points: 0, Legacy Rep: 28
    Location: Netherlands

    mwatts Martin

    Yes, you have made me rethink my initial decision, which was based on the concept of selling the boat as a kit, consisting of pre-cut sheets of steel.

    If I want to use different materials, I will have to study and dig in to wooden construction though.

    How exactly will you go about the build? Will all the wood eventualy be covered with a layer of fiberglass?
     
  3. Eric DEBORDE
    Joined: Oct 2009
    Posts: 31
    Likes: 10, Points: 0, Legacy Rep: 160
    Location: New Caledonia

    Eric DEBORDE Junior Member

    MWatts / Sandwich plywood or foam

    I had fun to work with plywood and fiberglass for the proto.
    For the next one I will use sandwich core construction with fiberglass laminates inside and out and uni carbon in some special places. Those foam or honeycomb sandwich are Weigh Less than glassed plywood and I espect 700kg for the 12m hull. You can keep the concept of selling the boat as a kit, consisting of pre-cut sheets of sandwich.

    ref : http://www.diabgroup.com/europe/literature/e_pdf_files/man_pdf/sandwich_hb.pdf
     
  4. mwatts
    Joined: Jul 2009
    Posts: 66
    Likes: 1, Points: 0, Legacy Rep: 28
    Location: Netherlands

    mwatts Martin

    I don't know the sandwich material. How thick are the plates? Will it bend like plywood or steel? Could you construct a hull like in my design (for instance the twisted bottom plates) from sandwich?
     
  5. FAST FRED
    Joined: Oct 2002
    Posts: 4,519
    Likes: 109, Points: 63, Legacy Rep: 1009
    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    I Wonder if the central hull (similar to a Box Keel) provides lift at speed?

    As a water ski would?

    If it does , do the amas hold any weight at speed , or just stabelize the vessel?

    FF
     
  6. mwatts
    Joined: Jul 2009
    Posts: 66
    Likes: 1, Points: 0, Legacy Rep: 28
    Location: Netherlands

    mwatts Martin

    FF: Are you referring to my design or Eric's? As far as I can tell, Eric's central hull is very narrow, so I would not expect much lift. I think the speed advantage is mainly in the high Froud numbers.

    The central hull of my design is approx. 20 cms wide, which isn't very much either, but I estimate more than Eric's. So there could be a little more lift, but my expectation is not that it will be very much. If you can compare it to a mono ski: you need quite some speed to keep a grown man out of the water.
     
  7. Eric DEBORDE
    Joined: Oct 2009
    Posts: 31
    Likes: 10, Points: 0, Legacy Rep: 160
    Location: New Caledonia

    Eric DEBORDE Junior Member

    3/4 cm lift at 18 knots with 2 deg hull trim

    At speed amas are dynamic stabs only.
    I have tried to limit wet surface has much as possible on amas.
     
  8. HJS
    Joined: Nov 2008
    Posts: 332
    Likes: 44, Points: 28, Legacy Rep: 288
    Location: 59 45 51 N 019 02 15 E

    HJS Member

    Box keel and planing amas


    Like this one?!
    With my expierience, the amas do not hold much weight, mostly stabilizing.
    Therefor is the ama position importend, both longitunal and vertical.
    And that is related to the designed speed.
    Remember that the amas are planing at very high relativ speed, FnV.

    js
     

    Attached Files:

  9. erik818
    Joined: Feb 2007
    Posts: 237
    Likes: 20, Points: 0, Legacy Rep: 310
    Location: Sweden

    erik818 Senior Member

    I've read all posts on "faux tri" power boats with great interest. What I have in mind is a 10 m long, 3 m wide boat with a displacement of typically 2.5 tons (minimum 2 tons, maximum 3 tons). Max speed would be 15 kn and typical cruising speed 12 kn.

    How should the results obtained or predicted with faux tri hulls of similar length be scaled to get a first estimate of the power requirements for this hull at these speeds?

    Erik
     
  10. Guest625101138

    Guest625101138 Previous Member

    Eric
    I have made quite a few stabilised monohulls in the form of pedal boats. This is a nice scale to work with and gives me a lot of feel for how the hulls perform. I can get 6kts with 130W from the latest. I have been using GODZILLA to generate the lowest drag hull form for the design displacement and power level. This is the latest:
    http://www.boatdesign.net/gallery/showphoto.php/photo/15138/size/big/cat//ppuser/18624

    My eventual aim is a solar powered coastal cruiser. One variation linked here is designed for 8kts with 1kW, one up:
    http://www.boatdesign.net/gallery/showphoto.php/photo/15019/size/big/cat//ppuser/18624

    You have achieved much the same results as I have demonstated. My interest is in a zero fuel boat so my speeds are a little lower.

    I design and build the complete system. With easily driven hulls like this you can get much higher propeller efficieny using low area blades. I am using ratios less than 10%. There is a lot of information on the pedal power thread on the props I design. The WHIO uses a hand fabricated prop to improve efficiency. With props like this you can get efficiency around 90% compared with about 70% from a typical outboard prop in your speed of interest.

    Rick W
     
  11. Eric DEBORDE
    Joined: Oct 2009
    Posts: 31
    Likes: 10, Points: 0, Legacy Rep: 160
    Location: New Caledonia

    Eric DEBORDE Junior Member

    Pics collected on the WEB

    Pictures are better than words so voila my collection
    1
    [​IMG]
    2
    [​IMG]
    3
    [​IMG]
    4
    [​IMG]
    5
    [​IMG]
    6
    [​IMG]
    7
    [​IMG]
    8
    [​IMG]
    9
    [​IMG]
    10
    [​IMG]
    11
    [​IMG]
    12
    [​IMG]
    13
    [​IMG]
    14
    [​IMG]
    15
    [​IMG]
    16
    [​IMG]
    17
    [​IMG]
    18
    [​IMG]
    19
    [​IMG]
    20
    [​IMG]
    21
    [​IMG]
    22
    [​IMG]
    23
    [​IMG]
     
  12. Eric DEBORDE
    Joined: Oct 2009
    Posts: 31
    Likes: 10, Points: 0, Legacy Rep: 160
    Location: New Caledonia

    Eric DEBORDE Junior Member

    24/47

    24
    [​IMG]
    25
    [​IMG]
    26
    [​IMG]
    27
    [​IMG]
    28
    [​IMG]
    29
    [​IMG]
    30
    [​IMG]
    31
    [​IMG]
    32
    [​IMG]
    33
    [​IMG]
    34
    [​IMG]
    35
    [​IMG]
    36
    [​IMG]
    37
    [​IMG]
    38
    [​IMG]
    39
    [​IMG]
    40
    [​IMG]
    41
    [​IMG]
    42
    [​IMG]
    43
    [​IMG]
    44
    [​IMG]
    45
    [​IMG]
    46
    [​IMG]
    47
    [​IMG]
     
  13. Eric DEBORDE
    Joined: Oct 2009
    Posts: 31
    Likes: 10, Points: 0, Legacy Rep: 160
    Location: New Caledonia

    Eric DEBORDE Junior Member

    48/53

    48
    [​IMG]
    49
    [​IMG]
    50
    [​IMG]
    51
    [​IMG]
    52
    [​IMG]
    53
    [​IMG]
     
  14. Eric DEBORDE
    Joined: Oct 2009
    Posts: 31
    Likes: 10, Points: 0, Legacy Rep: 160
    Location: New Caledonia

    Eric DEBORDE Junior Member

    Some new pics of Crossbow 12m

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    Toilet on front, then shower, then master bed room and guests beds.
     

  15. WestVanHan
    Joined: Aug 2009
    Posts: 1,374
    Likes: 56, Points: 0, Legacy Rep: 746
    Location: Vancouver

    WestVanHan Not a Senior Member

Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.