chine height at bow and at transom

Discussion in 'Boat Design' started by Hunterr, Jul 15, 2015.

  1. Hunterr
    Joined: Jun 2015
    Posts: 29
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: Korea

    Hunterr Junior Member

    When making Chine height at bow or transom higher, What is pros and cons?
    Is the chine relating to only rolling period?
    Now i intend to make chine height at bow higher in order for boat to have fine visual.
  2. Rurudyne
    Joined: Mar 2014
    Posts: 1,170
    Likes: 40, Points: 48, Legacy Rep: 155
    Location: North Texas

    Rurudyne Senior Member

    Two things: First, I just listened to How to Talk Minnesotan so even though I'm a Texan there are similarities so I hope none of that seeps in, though it probably will.

    Secondly, this is something I've wondered about myself. I mainly have approached it with relation to slamming, which may be odd given that I'm not looking to go fast. As I've tried to get a v-berth situated as far forward as I can in my DelftShip model it does seem apparent that that lovely high chine cuts in on your space a bit; however, it seems to me that not slamming and v-berths are a good combination, especially if the slamming happens while at anchor in the ICW because you've slipped away from where you thought you were and there's some weather about that could be better. Now others have praised the far forward head as was the fashion with those lovely Lake Union boats and with these, which will actually be used underway, I can see a good argument to having a high chine line even if it means you're reaching behind you for the toilet paper unless, of course, you are okay with your problems coming back to visit you. Naturally if you only plan on going slow in a lake you can choose without fear of making a wrong choice. I'd like to say I'd thought deeper about the subject but if I acted like I had I'd be just fooling myself. Whatever.
  3. Grant Nelson
    Joined: Feb 2005
    Posts: 210
    Likes: 12, Points: 0, Legacy Rep: 163
    Location: Netherlands

    Grant Nelson Senior Member

    Keep your chine a pecent or two of beam below the watterline aft. Forward your main concern is keeping a sharp enough 'V' to avoid pounding. I. Believe its around 50 degrees in section view where the keel comes out of the water. You can go dwn to 40 in protected waters and up to 60 in open seas. As Rurudyne indicates this means also the higher your chine at the bow the less beam you will have for accomidations. I assume you are talking about a plannong speedboat.
    1 person likes this.
  4. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,401
    Likes: 1,035, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Chine of what ?
  5. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 494, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The best advice for this poster maybe just rude, simply put, open your textbooks and keep studying. In a nutshell there are so many variables, that questions like these all but impossible to answer and the sign of someone, very early in their studies. Keep studying and we will not tell anyone you asked, a few years from now when you realize the answers and that you asked this, a few years prior.
  6. Jamie Kennedy
    Joined: Jun 2015
    Posts: 541
    Likes: 10, Points: 0, Legacy Rep: 117
    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    I think Grant Nelson answered it well but it is difficult to discuss the chine in the absence of context. The chine is primarily a consequence of what you are trying to achieve in terms of overall hull shape and volume, for both hydrostatic and planing and handling characteristics. The distribution of weight is also significant. Putting a bridle and saddle on a pig does not a race horse make.
  7. Hunterr
    Joined: Jun 2015
    Posts: 29
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: Korea

    Hunterr Junior Member

    recommanding book plz.
  8. SaltOntheBrain
    Joined: Feb 2007
    Posts: 123
    Likes: 7, Points: 18, Legacy Rep: 87
    Location: crosbyton, TX

    SaltOntheBrain Senior Member

    Start with Dave Gerr's "The Nature of Boats".
  9. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 494, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The Nature of boats, will not provide the subtle design answers he's been looking for. He needs a full blown course or an apprenticeship.
  10. kerosene
    Joined: Jul 2006
    Posts: 1,262
    Likes: 187, Points: 63, Legacy Rep: 358
    Location: finland

    kerosene Senior Member

    But nature of boats is a good 1st book nevertheless.
  11. gonzo
    Joined: Aug 2002
    Posts: 15,935
    Likes: 1,287, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The profile has to be considered in relation with the beam and entry angle. A very narrow hull will handle waves well with a relatively flat bottom.

  12. Eric Sponberg
    Joined: Dec 2001
    Posts: 2,010
    Likes: 216, Points: 73, Legacy Rep: 2917
    Location: On board Corroboree

    Eric Sponberg Senior Member

    Interestingly, no one that I know of in the modern world of boat design has ever written or discussed any guidelines as to how to make a chine line and at what heights the chine should be from bow to stern. I have always advocated that this is an excellent field of study for someone doing a master's or doctor's thesis in college.

    That said, if you are working on a powerboat design, then the chine at the stern should be just slightly under water, as Grant said, and then a mix what looks good and what the requirements would be for the deadrise of the bottom surface in the forward half of the boat, also as Grant alluded to. The sweep of the chine line is done pretty much by eye as anything else, kind of by a gut feeling for what you think is going to work. There are very few guidelines to follow.

    In the last two decades or so, some designers, myself included, have added chines and lifting strakes to sailboat hulls. Actually, chines go back much further--centuries--when boats were made of planks and the some of the butt joints between planks were chines. But the modern era of the last few decades the designers have been putting chines and strakes in rounded hullforms simply to benefit from the hydrodynamics that chines and strakes provide. Witness the last few runnings of the Volvo Round the World Races--almost all chined hull forms. For these boats, the styles vary--some will have the chines partially submerged at amidships or aft, some will not be submerged at all anywhere along their lengths when in the upright position. Again, there are no hard and fast guidelines--you draw what you think looks right, try to justify your choices one way or another, and move on. That is one of the nice things about boat and yacht design--you can let your imagination go with the flow, so to speak, and come up with intriguing vessels.

    Good luck,

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.