What is world's biggest planning hull boat and how fast?

Discussion in 'Boat Design' started by Squidly-Diddly, Sep 16, 2020.

  1. baeckmo
    Joined: Jun 2009
    Posts: 1,654
    Likes: 670, Points: 113, Legacy Rep: 1165
    Location: Sweden

    baeckmo Hydrodynamics

    Thanks John, (both of you....!). That warms a frozen heart, now let's get on forwards :)
     
    DogCavalry likes this.
  2. gonzo
    Joined: Aug 2002
    Posts: 16,790
    Likes: 1,714, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    That was in response to your claim that burnt fuel is KE. It appears that it meant that in that context it was the energy in the fuel converted to kinetic energy.
     
    DogCavalry likes this.
  3. BMcF
    Joined: Mar 2007
    Posts: 1,173
    Likes: 182, Points: 63, Legacy Rep: 361
    Location: Maryland

    BMcF Senior Member

    I worked with Rolf back in the 80s as we sorted out the various issues encountered in getting the KaMeWa jets properly integrated with the SES vessels we were developing and building back then.
     
  4. BMcF
    Joined: Mar 2007
    Posts: 1,173
    Likes: 182, Points: 63, Legacy Rep: 361
    Location: Maryland

    BMcF Senior Member

    Bodo is indeed that....which is why I've enlisted his help and expertise on occasion. When it comes to propulsion..it vastly exceeds my own.
     
  5. BMcF
    Joined: Mar 2007
    Posts: 1,173
    Likes: 182, Points: 63, Legacy Rep: 361
    Location: Maryland

    BMcF Senior Member

  6. DogCavalry
    Joined: Sep 2019
    Posts: 3,076
    Likes: 1,570, Points: 113
    Location: Vancouver bc

    DogCavalry Senior Member

    You are right. Brevity is only the soul of wit if you're Oscar Wilde. I meant to say that, all other things being equal, you vessel is driven by reaction forces from momentum imparted to the working fluid (water or air), but the power required to accelerate that fluid depends on the kinetic energy imparted to the fluid, so half the fluid at twice the velocity gives the same thrust, at twice the power requirement.

    Of course Baeckmo very eloquently expressed exactly that in his first post in this particular exchange. Jehardiman's contribution expanded on that. To the effect that while generally speaking, I was correct. An open prop can be substantially more efficient. However.... there are regimes where the limitations on props are not the same for pumps, and under those conditions, a pump is the correct answer for the system as a whole. Well, it only takes a boot up the arse from a guy in Japan, and even an old Dog(cavalry) can learn something new.
     
  7. Squidly-Diddly
    Joined: Sep 2007
    Posts: 1,958
    Likes: 176, Points: 63, Legacy Rep: 304
    Location: SF bay

    Squidly-Diddly Senior Member

    anyone got a basic graph/chart of power to weight ratios required for planing boats, especially at the higher weights?
    Maybe a 3D graph that also factors in hull size/planning area?

    Maybe with flat, shallow and deep Vee hulls?
     
  8. DogCavalry
    Joined: Sep 2019
    Posts: 3,076
    Likes: 1,570, Points: 113
    Location: Vancouver bc

    DogCavalry Senior Member

    Savitsky pointed out that hull size is irrelevant, only weight, beam, and deadrise angle.
     
  9. jehardiman
    Joined: Aug 2004
    Posts: 3,762
    Likes: 1,152, Points: 113, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Generally results like those are presented as a graph of total resistance/weight vs volumetric Froude number for standard series hull forms. Try the DTRC (or whatever DTMB was calling itself at the time) Series 62 (codified into SNAME Bulletin 1-23), the DTRC Series 65 papers, as well as Hadler's expansion of Savitsky's work (SNAME Trans. Vol 74).
    The fact that planing hull data is presented as Rt/W vs. Fnv allows us one last touch on the whole propulsor-prime mover- bunker issue. Yes, specific energy of the fuel plays a part, but only in the weight of the overall vessel. Because in actual practice there is not really that much to choose from in the weight of installed propulsor(s). It is only the weight of the prime mover(s) and the bunker that actually drive overall displacement (i.e. weight) assuming that the rest of the loadout is identical. This means that a more power dense fuel results in higher speed and/or longer range. This is why the gasoline engine supplanted most others in the small planing vessel market.
     
    bajansailor and DogCavalry like this.
  10. HJS
    Joined: Nov 2008
    Posts: 481
    Likes: 128, Points: 43, Legacy Rep: 288
    Location: 59 45 51 N 019 02 15 E

    HJS Member

    ...... and LCG which indicates the bottom aspect ratio.
     
    Last edited: Jan 31, 2021
  11. gonzo
    Joined: Aug 2002
    Posts: 16,790
    Likes: 1,714, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Small planing vessels are usually designed for a short distance range. When vessels are designed for longer range, diesel fuel is customary because of its higher energy density.
     
  12. TANSL
    Joined: Sep 2011
    Posts: 7,369
    Likes: 699, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    I'm curious, how does the design of a planing hull change (hull not a boat) depending on whether it is for short distance range or for long distance range? And, on the other hand, how is energy density measured?, amount of energy, joules, per cubic meter of ship ...?
     
  13. gonzo
    Joined: Aug 2002
    Posts: 16,790
    Likes: 1,714, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Energy density is measured as energy/volume or energy/mass. The units are irrelevant as long as they are consistent. Diesel fuel has a higher density than gas by either criterion.
     
  14. TANSL
    Joined: Sep 2011
    Posts: 7,369
    Likes: 699, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member


  15. bajansailor
    Joined: Oct 2007
    Posts: 3,596
    Likes: 1,560, Points: 113, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Just an observation - sadly so many threads on here nowadays invariably stray away from the original topic and develop into a peeing contest about semantics and definitions with subtle insults being hurled around - please, lets just stay on topic?
     
    Ad Hoc, jehardiman, BlueBell and 3 others like this.
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.