A Bizarre Question

Discussion in 'Boat Design' started by Rurudyne, Dec 8, 2014.

  1. Rurudyne
    Joined: Mar 2014
    Posts: 1,170
    Likes: 40, Points: 48, Legacy Rep: 155
    Location: North Texas

    Rurudyne Senior Member

    Okay, I'm guessing there would be absolutely no effect on any boat with a wide transom, like a Cape Cod catboat, but when a double ended boat or one with a narrow transom has, as has occasionally been the fashion on some craft like some sidewheelers, an unusually long rudder that is also above water would such a thing affect the boat's wave system?

    I can see why a normal transom should void any such benefit since the water is likely going to 'see' the edge of the transom as the end of the boat.

    Just something really, really random I've been wondering about that touches on hydrodynamics.
     
  2. NoEyeDeer
    Joined: Jun 2010
    Posts: 983
    Likes: 32, Points: 28, Legacy Rep: 300
    Location: Australia

    NoEyeDeer Senior Member

    Short answer: no.
     
  3. doug9694
    Joined: Dec 2014
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Temperance

    doug9694 Small Engine Mechanic

    A slow moving boat would set deeper in the water so a narrow transom would let the water flow back more gradually reducing drag. As you get up on plane a wider transom would push the boat higher decreasing surface area and drag. Some cigaret types have stepped hulls to decrease
    surface area. At least that is what I think is the reason for the steps. Others have what was described as whale tail. The transom is a foot or two higher for a couple feet. This I think is so when you are on plane the rest of the boat is lower.
     

  4. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I think you're talking about a barndoor style of rudder on displacement craft. In a technical sense it would have a very slight affect on the wave train, but at displacement speeds not something you'd notice over say a well immersed spade. On a small light boat, you would feel a difference at the helm if you switched from a barndoor to a spade, though the affect on the wave train would be minimal.
     
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.