Boat design with no to little curves?

Discussion in 'Boat Design' started by Xyberz, May 23, 2014.

  1. Ike
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    Ike Senior Member

    Xyberz, I am not an unbeliever. I have been around boats all my life, everything from dinghies to ocean going ships, sail and power, and canoes. I never liked kayaks. I just didn't seem to get the hang of it. I spent 20 years in a Coast Guard uniform, and another 14 as a civilian USCG engineer in boating safety. I suppose I am on the over cautious side because of my experience but just the same, I have seen people do things the average boat owner wouldn't even consider doing. It's amazing just how stupid some people are. Ever hear of the Darwin Awards?

    But you are not one of these. You have the good sense to ask questions of people who have the knowledge and experience.

    I have been to Hawaii (my brother lives on Kauai). I went sailing in Pearl Harbor. It is truly beautiful there. Yes I do know about people fishing from kayaks. But I also have an online feed of the Coast Guard's Search and Rescue cases and darn near everyday they are looking for someone who took a Kayak offshore. Not necessarily in Hawaii though. You normally don't see any of this on the mainstream news, it isn't dramatic enough, unless it 's a local station with a local news item, or the Coast Guard Channel on Cable. It has to be something catastrophic like a Cruise liner or a massive oil spill to make the evening news.

    What we are saying is that it would be simpler and safer for you if you went with a design done by a professional. Actually someone mentioned the 13 foot Boston Whaler. It's probably one of the few boats I would use the term unsinkable for. Perfect for what you are proposing. But they are not cheap. Even used ones. There are similar designs for wood. They are easy to build and don't require any special tools or molds. You can build them in your garage (or on a picnic table like my 12 foot rowboat).

    Good luck. Let us know what you pick, and post your progress building it here. We love to see boat projects, especially with lots of photos and/or video.
     
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  2. Rastapop
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    Rastapop Naval Architect

    One more vote for buying something already built to a proper design here.
     
  3. upchurchmr
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    upchurchmr Senior Member

    Everyone starts somewhere.
    No telling where the OP will end up.
    All we can really do thats valuable is to give reasons for our opinions.
     
  4. NoahWannabe
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    NoahWannabe Junior Member

    It also depends on what fishing is.
    Four guys (160# each) with a burlap and sandwiches for lunch in 14 footer with 10 hp OB would be 750# load. Doable.
    Three guys (230# each) with Yeti iceboxes full of ice, 2 case of beer, bbq for lunch, in 14 footer with 225 hp OB would be 1200# easily. Yes over loaded.

    Curved flat bottom (good rocker on flat dory bottom) with moderate speed can be very seaworthy.
     
    Last edited: May 27, 2014
  5. Xyberz
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    Xyberz Junior Member

    Wow, already a nice wealth of information! It's greatly appreciated towards getting me toward the right direction. I just recently found this website that seems to talk about "stealth" boats and it seems that most of these already built boats have the very little to maybe no curves. I'm not sure how practical it would be to be used as a fishing boat

    http://covertshores.blogspot.com/2010/06/alligator-sea-lion-class-semi.html

    It seems that it's safest to have a boat that has high walls, well for at least ocean going fare. Bass boats that I see are very shallow hull design with very small degree of hull "V" angles. Would this be terrible for ocean use?
     
  6. upchurchmr
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    upchurchmr Senior Member

    Please don't pay attention to anything about stealth boats.
    The reasons for stealth will always compromise a good boat. To just be "good" while having stealth you will have to go to extremes. Unless you want to do a little dope running on the side.

    Higher walls or more "freeboard" prevents bigger waves from coming in the boat. That's good when you can't swim in easily, or someone else can't swim easily, like children or older people (like me :()
     
  7. ondarvr
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    ondarvr Senior Member

    I always ask the person what the reason is for building their own boat, if you want a project, love doing this type of work, have a good deal of time and like to build your own toys, then go for it.

    If you're looking for a less costly way to get on the water and think this will be cheap and easy, forget about building it yourself.

    Most older glass boats turn into an eyesore in the side yard and start to rot away, and can be had for little or no money, the no money ones are what you're looking for.

    If you want to build or customize a fishing boat these old rejects can be a good platform to start with. Find a hull that fit's your needs and rebuild the interior to whatever you want it to be, this saves you a ton of time, money and labor. Sometimes you can use more than just the hull, other parts and/components can be good also, frequently they even come with a motor.
     
  8. philSweet
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    philSweet Senior Member

    Xyberz, get over your fear of curves. Any low powered boat needs its curves to be seaworthy, and even high powered ones troll slowly and benefit from them. At 10 hp or so, you are stuck at hull speed with four aboard (6mph). You are probably looking at >1400# all up, and 75# per hp is a reasonable small craft number for getting up on a plane.

    I converted a 16' plywood sailboat that I built into a motor skiff for fishing and trap tending in Florida. Usual crew was 2, but often 3 (200 - 300 pounders). Add 400# of traps, 150# of misc. gear, a 125# motor, and a 400# hull (too light for the job, hull designed for sailing power and less weight, but top quality material, custom plywood manufactured for me by Bruynzeel - all A surface veneers with no joints at all in 16' lengths - and Honduran Mahogany frames. It cost a small fortune, more than I spent on four years at college; but it gave me a better education over the 25 years I kept it.) It could barge along at about twelve knots heavily loaded and cruise at 16 knots with an ordinary load with a 25 hp Yamaha 2 stroke outboard. The one thing that it was in spades was seaworthy. Pulling traps oceanside in thirty knot trade winds, I'd be ten feet shorter than anything else out there. None of the twenty foot runabouts would go out. And Floridians aren't shy about running offshore in small craft, either.

    So study the small craft that have been used in your area for the work you want to do and copy them as well as you are able to. Forget about customizing anything for now. You can begin to do that when you start the first round of major maintenance in three or four years time. My skiff was quite a different beast after 25 years compared to what it was when I splashed it.

    Traditional boatbuilding in wood has 4000 years of process development behind it. It is in fact a very easy thing to learn how to do, and can produce virtually any boatlike shape you want. It is also very cost efficient.

    Plywood is a good deal trickier, and it is quite challenging to produce the shape and the look you want. I would strongly recommend using proven plans, of which there are hundreds to choose from, for your first build. I think this would be far more satisfactory than trying to avoid learning to build boats by assembling boxes.
     
  9. johnhazel
    Joined: Jun 2008
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    johnhazel Senior Member

    If you ease the length requirement to 24ft then you might look at a banks dory type design. That would be a few frames and plywood sheets. 5 hp would push it much faster than it would a 12-14 f one. And, a banks dory has a real manly look and history.

    http://en.wikipedia.org/wiki/Banks_dory
    http://4.bp.blogspot.com/_3D7r7cBXdMs/S9e-NRVVDGI/AAAAAAAAB9g/oU1g1YJjnBM/s1600/banks dory60.jpg
    http://www.spirainternational.com/images/gl_labr_a.gif

    http://www.spirainternational.com/study/LabradorAluminumStudy.pdf
     
  10. Xyberz
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    Xyberz Junior Member

    Man, such awesome replies and suggestions guys! I apologize if I don't respond to every person and I appreciate every little bit of input. I've been doing an insane crash course over boat designs and what has worked and even though a little more difficult, finding out what doesn't work.

    You guys are very right about the boat not having curves. As you may have guessed as soon as you saw my title, that I have absolutely 0% knowledge about boat building and design in general besides what I typically see out there.

    Just like all things in life, I've learned that there are many different ways to go about certain subjects like boat design. Each has it's own pros and cons. Since I'll be most likely using a boat in the ocean maybe about 90% of the time, it should be focused on being able to safely traverse what the ocean can throw at you. Well at least to a certain extent. I mean even a ***** wouldn't go out in a small or maybe even a big boat in a raging storm with choppy and insane waves.

    With all the suggestions given so far and with my own research, how do you guys feel about twin vee hull designs? Apparently from the video from a manufacturer, it's supposed to be considerably more stable than your deep vee hulls in rough and choppy water yet still offer even better efficiency and have higher speeds than flat bottom boats. The only thing they didn't touch upon is the loading capacity. But I'm thinking that this is a good design since it's technically a catamaran and has been used in the Polynesian culture for centuries.

    Also for boat design on the computer, I see that some people use Rhino 3D. Is that the best software for boat building? I've used Autodesk Inventor before to design an invention that I was working on and got used to it. Rather than looking to learn something completely new, I'm hoping I could just use what I have experience to save some time and effort.
     
  11. upchurchmr
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    upchurchmr Senior Member

    Such a boat is called a catamaran.

    The only problem is that if you sit in the middle of the boat between the hulls you will be sitting quite high out of the water. Also the connecting structure needs to be above any waves you will be in or it will not have less drag.
    If the boat is wide it will certainly be more stable or less tippy, but the hulls have to be big enough for you to walk to the edge of the boat without being completely sunk. Probably for 2 people at a time to be safe. Normally it has to be wide because a narrow gap between the hulls also increases drag.

    Last, there is typically more weight of hull - more surface area to build.
    Here is a boat just to look at. You would need something bigger I think, and it looks a little narrow to me (because it is designed for one person rowing not a motor).
    http://www.duckworksbbs.com/plans/gumprecht/cat12/index.htm
     
  12. John Perry
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    John Perry Senior Member

    I have used Autodesk Inventor myself in the past and I think its excellent software but needless to say, its not the only option. More recently I have been using Solidworks and that is also good and provides a broadly comparable range of features to Inventor, as do various other alternatives.

    Since you are already familiar with Inventor, and assuming that you want to make a prompt start on your boat designing, I can't see a reason to start by switching to software that you are not familiar with.

    As I said in a recent post in the 'Software' section, I would not want to be without the parametric modelling capability included in both Inventor and SolidWorks. I didn't think Rhino offered that but I am advised that Grasshopper (sounds like a rather different kind of animal to Rhino!) can be used with Rhino and is parametric. However, looking at webpages about Grasshopper I am not sure how it compares to Inventor or Solidworks, at first sight it looks totally different but maybe I am missing something.

    Best wishes for your boat designing and building, reading between the lines I suspect that you may be more familiar with boats than you let on. Even if that is not the case it is a potentially interesting learning experience.
     
  13. Xyberz
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    Xyberz Junior Member

    Nice link and that'll help better my understanding of catamaran's for sure. Is there a certain formula to figure out how much width catamaran's I need to support a specific weight? I'm thinking it's not your conventional calculation used for typical monohull design?

    One of the links I went to in research of catamaran power boats is in http://twinvee.com

    From looking at the pictures and reading more about their design, it seems like it probably won't hold as much in internal cavity as a monohull normally would figuring the same overall width. But there are some sacrifices that need to be made right? I like their first video in their videos section describing the benefits of a cat over mono.

    I know this is a little more advanced, but I'm thinking that eventually, if not at the same time when I finally get to building anything, of adding a hydrofoil to further increase the efficiency of the design as they stated it does with TwinVee's cat. With the additional added lift with the hydrofoil, it will help ensure that the center section doesn't touch the water like you said thus causing drag.
     
  14. Xyberz
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    Xyberz Junior Member

    Ah, thanks for the input. Seems like what I've used before will work well with my endeavour.

    P.S. Trust me, when I meant crash course on boat building I really meant it! Hahaha, what you think I know so far is the great info you have all given to me and what I've only researched so far since I've started this thread literally. Before this I never thought or wanted to build a boat in my entire life. But my passion for fishing calls for something that seems I can't do without to further my fishing experience. Also fishing by yourself is great, but fishing with friends and family is something truly worth treasuring in life. Sadly you can't land the really big ones from shore unless you're maybe one in a million/billion. Unfortunately I don't have that much patience but I do to learn something like boat building!!! ;)
     

  15. Rurudyne
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    Rurudyne Senior Member

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