How do we compare two hulls?

Discussion in 'Hydrodynamics and Aerodynamics' started by tea, Apr 15, 2017.

  1. tea
    Joined: May 2016
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: usa

    tea New Member

    Say one hull is one hull is slender (∇/L^3)= 8, in nature and another one has slenderness ratio of 4.5. If I were to make them a full model of 40m and test for resistance and motions, This could be an unfair comparison. Say I may later one slender its length will decrease. SO whats are the parameters to be kept contents to make a fair comparison. Assuming The bulky hull's initial parameter are double the slender ones. ?
     
  2. jehardiman
    Joined: Aug 2004
    Posts: 2,827
    Likes: 383, Points: 83, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Hullform is never selected in vacuo. Transport capacity, propulsion, accommodations, tankage are all in the trade space.

    Also, for what it is worth, slenderness ratio is only relevant between like hullforms, not equal displacements. So depending on the two hullforms, slenderness ratio could just be a meaningless factoid with no relevance for comparison, like the admiralty coefficient between a planning boat, VLCC, and a torpedo.
     
  3. oataru
    Joined: Nov 2010
    Posts: 8
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: Thailand

    oataru Junior Member

    Note that Slenderness Ratio (SR=Lwl/Vol^0.333 ; SI units)

    Once you fix the full model length as 40 m for both hull,
    The more slender hull (SR = 8) would have displacement as 125 t in fresh water while the other hull would have 1,000 t.

    Obviously, the smaller boat, which is the former one, would have lower resistance but larger motion at sea.
    Anyway, you are comparing apple with durian.
     
Loading...
Similar Threads
  1. MoeZ
    Replies:
    0
    Views:
    271
  2. myszek
    Replies:
    5
    Views:
    594
  3. xanthar
    Replies:
    1
    Views:
    919
  4. Will Fraser
    Replies:
    13
    Views:
    1,886
  5. big_dreamin
    Replies:
    19
    Views:
    2,909
  6. Jgerstemeier
    Replies:
    8
    Views:
    1,473
  7. laserek
    Replies:
    20
    Views:
    4,722
  8. jcamilleri
    Replies:
    18
    Views:
    5,348
  9. John Perry
    Replies:
    89
    Views:
    19,151
  10. Erwan
    Replies:
    12
    Views:
    2,505
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.