Pointers about my 6.7m sailing boat design (total noob)

Discussion in 'Boat Design' started by ArchiSail, Mar 21, 2020.

  1. clmanges
    Joined: Jul 2008
    Posts: 308
    Likes: 19, Points: 18, Legacy Rep: 32
    Location: Ohio

    clmanges Senior Member

    Well, let's give him a little room to grow. He did say he's a noob, and he did have at least one design goal, and he followed it. Now it's been pointed out that his design goal led him to a powerboat instead of a sailer. Based on that, I'm going to say he's on the steepest part of the learning curve, which is where you don't know how to ask the right questions.

    Can somebody steer this guy toward a good beginning resource on sailboat design? Or should he just build and sail a PDRacer first? That would test his commitment, at least, and he'd learn the rudiments.
     
    bajansailor likes this.
  2. Ad Hoc
    Joined: Oct 2008
    Posts: 6,269
    Likes: 441, Points: 83, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    He is getting some good advice already.
    The problem is he is so only just at the beginning stage, which means endless Q&As, which leads to more Q&As and so on. His questions have far too many variables to begin with for him to narrow down and understand some basics.
    We can't tell him what he must do with his design, we can only offer guidance. But the guidance is already going over his head... that's the problem.!!

    It would be, as you suggest, worth the OP buying a book on yacht design and read, digest it, and read it again. Then look at what he's drawn and come back with more reasoned, structured and rationale questions, rather than a blunderbuss type approach - which won't help him much at this stage.
     
    bajansailor likes this.
  3. Mr Efficiency
    Joined: Oct 2010
    Posts: 8,133
    Likes: 393, Points: 83, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    OK, but probably a case of being cruel to be kind, if there is serious intent to proceed to the stage of building.
     
    bajansailor likes this.
  4. TANSL
    Joined: Sep 2011
    Posts: 5,899
    Likes: 233, Points: 73, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    In reference to post # 30 : Thank you Ad Hoc for your invaluable words, you do not know how much and how I appreciate it. Do you really believe that you cannot talk about technical questions of naval architecture, or whatever, without knowing the meaning of the word "noob"?
    At what point have I criticized anyone in this thread? I have simply warned that longitudinal imbalances must also be solved, that not only transversal ones must be considered. If that constitutes a criticism of someone, then, yes, I have criticized.
    Thank you, again, for your incalculable help analyzing my comments, and always with that generosity that characterizes you. "Superatis hostibus, regium est abstinere" and, of course ...IF IN DOUBT, ASK. :D
     
    Last edited: Mar 23, 2020
    bajansailor likes this.
  5. gonzo
    Joined: Aug 2002
    Posts: 13,934
    Likes: 481, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Before going any further, we could talk about getting to the stage of building. Since he is not a boatbuilder, he will make the usual mistakes that will have to be fixed as he goes. Realistically, the boat could be completed by an amateur in 8 to 9 months of full time work. To the OP: what is your time and money budget?
     
    bajansailor likes this.
  6. clmanges
    Joined: Jul 2008
    Posts: 308
    Likes: 19, Points: 18, Legacy Rep: 32
    Location: Ohio

    clmanges Senior Member

    Don't you think it's a little early to be talking about building? Maybe he'll learn really quickly, but at this point I'd have my doubts that he'd know a halyard from a downhaul. Look what's missing from his original post, for example: any mention at all of the sailing rig. And he drew a powerboat hull. Give him time to learn some of the basics first. For all we know he might decide he doesn't want a sailboat after all.
     
    bajansailor, TANSL and Ad Hoc like this.
  7. gonzo
    Joined: Aug 2002
    Posts: 13,934
    Likes: 481, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    I was responding to Mr Efficiency's post.
     
  8. ArchiSail
    Joined: Nov 2019
    Posts: 12
    Likes: 0, Points: 1
    Location: Stockholm

    ArchiSail Junior Member

    done some revisions to the hull, any thoughts??

    anny good resources to calculate waterline?

    upload_2020-3-27_14-5-17.png upload_2020-3-27_14-5-27.png upload_2020-3-27_14-5-37.png
     
  9. bajansailor
    Joined: Oct 2007
    Posts: 633
    Likes: 151, Points: 43, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Any thoughts?
    Sorry to be blunt, but how about starting from the beginning again?
    Use an existing boat as a reference to start off with, and then you can tweak it slightly to suit what you want.
    Can you honestly tell me which boat you find more attractive - your design, or the Red Fox 200 (re the link I posted previously)?
    That chine is going to metaphorically smack you in the chops every time you see the boat.
     
    BlueBell likes this.
  10. clmanges
    Joined: Jul 2008
    Posts: 308
    Likes: 19, Points: 18, Legacy Rep: 32
    Location: Ohio

    clmanges Senior Member

    Thoughts?
    I think you're still getting ahead of yourself, especially since you can't seem to make even a rough approximation of where the waterline would be. That's doable for anyone who knows algebra and basic solid geometry. You don't need many decimal places at this point, but you should be able to get within plus or minus ten percent. Hint: you have to know what it will weigh fully finished, provisioned and crewed, as well as where its fore/aft center of gravity will be.

    Go try that, and if the result has your transom below the waterline, you win the prize of having to scrap the design and start over. But by then you'll at least know what a quantity of anything weighs (be sure to record all that information). And the next time around you can get a little better precision in your calculations.
     
    BlueBell and bajansailor like this.
  11. BlueBell
    Joined: May 2017
    Posts: 1,018
    Likes: 147, Points: 63
    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Thoughts?
    Listen to the advice you're receiving,
    it's way better than you could ever imagine...
     
    bajansailor likes this.

  12. gonzo
    Joined: Aug 2002
    Posts: 13,934
    Likes: 481, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    It is still a terrible hull. There are so many fundamental errors that it is beyond just giving advice on how to fix it. The waterline is easy, although tedious. Add the weight of everything on the boat and the submerged volume multiplied by the density of water will equal it. The calculate the center of gravity of the boat and the center of buoyancy; they will be aligned vertically. That will give you the waterline. However, you first need to design a boat so you can have the structure, rig, hull thickness, etc. to be able to calculate weights.
     
    bajansailor and clmanges like this.
Loading...
Similar Threads
  1. newkid1
    Replies:
    5
    Views:
    1,397
  2. RatliffFranklin
    Replies:
    5
    Views:
    1,640
  3. jacob1234
    Replies:
    7
    Views:
    511
  4. almoniyot
    Replies:
    13
    Views:
    870
  5. gray duck
    Replies:
    6
    Views:
    524
  6. Cheapster
    Replies:
    6
    Views:
    604
  7. laukejas
    Replies:
    18
    Views:
    1,977
  8. Dolfiman
    Replies:
    13
    Views:
    914
  9. CaptJamesOBX
    Replies:
    24
    Views:
    866
  10. Angélique
    Replies:
    5
    Views:
    1,158
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.