FAT BOY DESIGN "what do you think ?"

Discussion in 'Boat Design' started by Buckie, Sep 30, 2007.

  1. Basjan
    Joined: Sep 2007
    Posts: 25
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: South Africa

    Basjan Basjan

    Hi buckie

    Still to much boat that will be under the water.
    Have you looked at cat or tri hulls, they could reduce the amount of boat that is submerged and still offer you the freedom to apply curves in line with your design.
     
  2. marshmat
    Joined: Apr 2005
    Posts: 4,127
    Likes: 149, Points: 63, Legacy Rep: 2043
    Location: Ontario

    marshmat Senior Member

    Bucky,
    From a styling and aesthetic standpoint, you generally need concern yourself only with what's above the waterline. While the shapes you depict aren't what many of us would consider practical, they are definitely distinctive. Above the waterline, you are free to do more or less whatever you want.
    Below the waterline is a different story. Nobody will see this most of the time, but this is what determines how the boat will perform. Look at boats of similar weight, length and speed to what you are thinking of, without considering appearance. Look only at how they perform at their design speeds, and how the hulls are shaped, not at how fancy the styling is or what features they have.
    What you'll find is that the lines you have drawn in your most recent post are more closely related to a semi-displacement hull, something that does about twelve knots, than to a fast planing hull. To plane, you need enormous, fairly flat bottom panels, so that the bottom loading is low enough and the dynamic lift high enough to lift the boat above its bow wave. In particular, planing a heavy boat requires tremendous lift right near the stern. The physics of the problem have, over time, resulted in variants of the shallow-V (for heavy boats or calm water) and deep-V (for high speed in rough water) forms as the best compromise solutions for these types of boats. Working from an underwater shape known to run acceptably will prove worthwhile in the end, even if it's not as creative or new.
     
  3. rotfix
    Joined: Oct 2007
    Posts: 19
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: austin

    rotfix Junior Member

    'nother newbie here. a few observations about the general size is that docking space will be difficult with a beam of that size. you'll end up at docks for much larger boats which won't be cheap. looks like you'll draw too much water to enter many smaller marina's, you'll be limited to areas for the big boats again. you'll still need to give consideration to the slings that marinas use on boats of that size, will they damage your hull? will you be able to rest it on land somehow for repairs/maintenance?

    from the overhead drawing, the large bulbous protrusions on the sides will severely affect performance. you're not only going to have a bow wave but the sides will create another side wave of sorts.

    last for me, the bow area looks similar to a ball in that it's rounded. would be difficult to get up front without sliding off. you might consider incorporating some walkways or flattened areas that would facilitate things such as anchoring, mooring, handling lines at docks, laying out in the sun, etc.

    i agree with the semi-displacement comparison. also, you might consider IPS, pod-style drives instead of conventional propulsion. performance is much better and efficiency is also improved. thx
     

  4. messabout
    Joined: Jan 2006
    Posts: 3,368
    Likes: 511, Points: 113, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    Buckie; I do not mean to discredit your efforts. Please do not take the cricisim from me or the other guys as a personal affront.

    Your drawings are imaginative, to be sure, but the things you have drawn will not work well as a boat. There are many principles of physics and Hydrodynamics that must be addressed when doing responsible boat design work. That stuff has been pretty well established over the last two hundred years or so. One may not stray very far from those generalities and expect favorable result. I respect your artistic flair, but art alone does not make a good boat. If you wish to do design work then you must become aware of the rules. That is why I suggested that you read and comprehend.
     
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.