Hard or soft chines & their effects on rolling

Discussion in 'Boat Design' started by Parke Brinkley, Jul 20, 2004.

  1. I plan to have a new fishing boat built & I need help deciding on which hull design to go with. Stability, crew comfort and fuel economy are my main objectives & I'm looking for a cruising speed of at least 20 knots with a 220-330 Cummins diesel. My two choices are:

    1. 26' x 9 1/2' Lobsterboat design with a deep forefoot, relatively no deadrise at the transom, unweighted keel, soft bilge, semi-displacement.
    2. 27' x 9 1/2' caroline style fishing design with sharp entry & 12 degrees of deadrise at the transom, lots of tumblehome, but hard chines.

    Which design would roll the least?
     
  2. mmd
    Joined: Mar 2002
    Posts: 378
    Likes: 18, Points: 0, Legacy Rep: 309
    Location: Bridgewater NS Canada

    mmd Senior Member

    I prefer the motion of the lobsterboat hull over the chined hull. While the chine boat will have a better speed potential, the chines cause rapid decelerations in the rolling motion, which can get rather fatiguing to those on deck.
     
  3. Parke

    Thanks MMD. From what I have heard the lobster boat keel also helps to reduce the rolling somewhat.
     

  4. dereksireci
    Joined: Jun 2004
    Posts: 163
    Likes: 3, Points: 0, Legacy Rep: 37
    Location: South Carolina

    dereksireci Senior Member

    Rolling

    In general a round bilge design will produce a longer period of roll compared to a hard chine hull. The semi-displacement hull will roll to a further angle of heel, but the vessel will return more slowly. A hard chine hull will tend to want to snap back much more quickly, producing discomfort for the passengers, especially with 12 degrees at the transom.

    I think the chosen power is better suited to the round bilge hull form too considering fuel consumption.
     
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.