Affordable seaworthy cruiser

Discussion in 'Boat Design' started by goodwilltoall, Jul 31, 2010.

  1. mydauphin
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    mydauphin Senior Member

    Ah, my chance to get in on this one. If you believe in the Bible literally then you also believe that Noah had God's Holy Spirit helping him every step of the way.
    Do you believe you do? If so build whatever you want... else save your life and get a proven design. Don't put God and the Coast Guard to the test otherwise.

    That said let me talk about the dimensions, etc...
    My first boat was a card board box painted with fiberglass resin inside and out. I was 10, I think. When I stepped in it, it was crushed by the weight of the water trying to get in. It had no internal support.
    So I built an internal structure, found out had to make boat bigger so I could fit in it. Then it got heavier, had to make structure and walls stronger. This happen several times, and I still had a boat that would not travel well until I figured It was easier to follow someone else's design.
    You don't design a boat by its dimensions, this is meaningless. Start from the inside out. What do you want boat to do. And you keep changing things until everything fits and works correctly. A boat is either a displacement or planning type. Your boat is neither. It should be a displacement boat, it needs to weight more, it will weight more. On home depot wood... You can use any material you want but Home depot will change its shape on you by the time it gets wet a couple of times. I believe Noah didn't buy his wood at HD. Check into marine plywood and epoxies. West systems website used to have some good procedures description and explanation. Also always cheaper to buy a used boat than build one from scratch. Later... Good luck
     
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  2. Eric Odle
    Joined: Jul 2010
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    Eric Odle Tugboat Mariner

    Noah used gopher wood, which was a kind of laminate held together with God only knows what... No really, only God knows...

    The proportions of this boat sound like a canal boat or a Dutch barge to me. Maybe there's your proven design concept to start with and modify as necessary.
     
  3. SteveMellet
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    SteveMellet Senior Member

    This thread is too good not to watch. Carry on, please.
    With a 3-masted-tree-trunks-for-masts-50foot-narrow-boat, you will need so much lead under the boat to stop it lying on it`s side, that you`ll sink it on launch. It`s ok though, the masts will float.
     
  4. mydauphin
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    mydauphin Senior Member

    Just for fun... Next time I go to Home Depot I am going to special order counter and ask for Gopher Wood. The looks will be priceless.
     
  5. SamSam
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    SamSam Senior Member

    The point of the thread is to gather knowledge but so far there has not been one question mark used or any questions asked by the original poster. It is all in the form of a stringent proclamation, flavored with superstition. This invites negative comments.

    I have a question that I can't find an answer to. What does the word 'design' entail, in relation to boats. Is a vague idea and a few concept drawings enough, or does it entail structure, materials, plans and projections? How far along the path does an idea become a design?
     
  6. SteveMellet
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    SteveMellet Senior Member

    "How far along the path does an idea become a design?"

    In my opinion, when it floats.
    Only then can it be established if it`s a good, bad, or ugly...design.
     
  7. apex1

    apex1 Guest

    Hmm,

    one might not be enough to handle that nonsense in #38........:D


    A vague idea and some stylish drawings don´t do Sam.

    A vessel floating right side up and performing as predicted is what makes a design.
    And of course materials, structural calculations, hydrodynamics etc. etc. are part of the game.
    Therefore the average amateur is not capable to "design" his boat, although almost all of them believe so. (and they pop up here twice a week with that beliefe)

    Regards
    Richard
     
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  8. kerosene
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    kerosene Senior Member

    I think the masts will have plenty of time to dry before the boat is done btw.

    When I was a kid we replaced our flag pole with new one made of spruce. Had it laid on supports every few feet and spun it around every few days to make sure it dried as straight as possible. Especially if skinned (which is much easier when the wood is fresh) the wood dries easily too fast and cracks.
     
  9. DennisRB
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    DennisRB Senior Member

    This thread rocks. A seagoing hyrofoil ark with green tree trunk masts, 8" draft and a flat bottom with Jesus as an autohelm. You should be looking at getting some investors to help finance this fine project. Maybe hand over some flyers at Christian fundamentalist churches and maybe get the kids at Sunday school to help built it. You could organize some sort of a friendly boat building competition with other religions. You could go to your local Mosque and see if you can get an Allah guided vessel built by your friendly local Muslims. When both boats are completed you can have a round the world race which will compare both the building and design skills of Muslims and Christians and the power of both of your Gods to guide your vessels safely. This would make an excellent reality TV show!

    :D
     
  10. Pierre R
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    Pierre R Senior Member

    Now Now let's be nice on this religious thing. Although I am a secular I am sensitive to the beliefs of others. No need to mock religion and no way to win.

    This guy is sitting in my backyard. I have to be nice :)
     
  11. Pierre R
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    Pierre R Senior Member

    Give Goodwilltoall a break. Right now he doesn't know enough to even ask what he really wants.
     
  12. goodwilltoall
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    goodwilltoall Senior Member

    sals dad,

    The design if obviously bolgeresque, have written to Suzanne with no response back. Understand the advice given and its not bad, but at this stage the baby steps are not necessary. Kind of like lets build a hut first, then log house, then a real house and pay architect even though you can do the same work. The site here is called boat design and you would think its geared to figure out solutions to boat design problems and then incorporate the solutions into the design.

    kerosene,

    The point of comparing balsa thats used in core structures is just to point out that the highest quality wood does not have to be used. The method is definetely different from sandwich construction. The first method as explained is basically oversized stringer construction which takes the longitudinal stresses. The 2 layers of ply stiffen the stringers and are the skin, the minimal lateral stresses are handled by it. It is not necessary to have characteristics of sandwich construction and reinforcement for the exterior skin other than to provide abrasion resistence at the bottom and chines. Interior skin is not need at all other than moisture barrier.

    Also since you do bring up sandwich construction as stated previously the overall hull thickness at sides will be 1.5" and the whole of the material used
    for construction will contribute to strength not just the skins. Not sure what thickness sandwich construction would require for a hull this size but it probably would be less than 1.5".

    The second method described is traditional coldmolding, both methods use epoxy which is profoundly more secure to build with than polyester. mydauphin voiced concern about home depot lumber getting wet, which I hope the epoxy will keep from happening, if it does get wet, plywood using the first method will swell more than expand and with frequent checkups any leaks could be addressed as with any other boat construction. The coldmolded way of building uses 3/8" x 1.5" strips which can have bigger distortions than prime lumber, but being so small dimensionally they cause small distortations and areas were water would enter would be visible and able to be corrected before major problems develop.

    Getting back to proportions, I would like some of you to consider a measurement to test the quality of the hull to make it seaworthy, efficient, and seakindly. Lets take the 50 footer and take away all appendages (fins, rudders, masts, keels, ballast, etc.), next take the three dimensional numbers every hull has(lenghth, height, width) and multiply which gives the number 2083 cubit foot for the 50 footer.

    Use that number and take any other hull and proportion it to equal it 2083.
    Now this I hope can be a starting point where certain qualities can be compared to each other. Keep in mind this will be only overall dimensions that you use to compare hull shape and nothing else. Know qualities can be made, for example "making it wider will result in either shorter hull, shorter height, or both. So if you make it wider what positive and what negative qualities will that add to the hull, or this hull is longer than that one and this is how they compare in this quality.

    Even though is simple, its a good way to compare. So think of any boat you can and see if it can stand in a head to head comparison with the Ark.
    You'll be surprised and I hope some of you can gracefully accept defeat.

    BTW, the 50 footer is not an extremely narrow shape. Successful boats such as International 110, Scandanavian square meter, Heresshoff "Marco Polo, MacGregor65, Spencer "ragtime" all had similar 5.5-6.0 to 1.0 length to beam ratios.

    From now on I will refer to the 50 footer as Jubilee, its easier.

    Jesus Christ, the Way, the Truth, and the Life.
    Peace.
     
  13. goodwilltoall
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    goodwilltoall Senior Member

    kerosene,

    Correct, masts do have to dry somewhat before they are put on, no mast is perfectly plumb, just not sure how much out of plumb is acceptable.

    Sals dad,

    Not trying to go my own way, going wherever the wind takes me. Hoping to use past proven designs and add them to Jubilee to make it better.

    Take a look at Ruell Parkers book cover "Coldmolded Boatbuilding" the shoal draft ocean going sailboat resting right up to the beach is beautiful.
     
  14. Pierre R
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    Pierre R Senior Member

    Goodwilltoall you seem to be seem to be making rhetorical statements with the idea of bringing consesus to your side. You will not find consensus here on your ideas. You know a few things but the gaps in your knowledge are chasms. You don't have enough here to even help you with the design.

    The design that you have will have you upside down in Lake Erie on a typical afternoon of 15-20 knots of wind and seas runing 2'-4'. The very steep short wavelength of the waves in Lake Erie will roll your design should you try to reach.

    The problem is not you're 6:1 length to beam ratio, your ark porportions or your Home Depot approach. The problem is in the lines of the boat and how it will react in waves. This is pretty basic stuff.

    I would heavily question a lot of the construction methods you seem to expouse but I have seen worse.

    A few suggestions. Get in your car and go over to Vikery and take a look at some decent materials. If purchase in quantity the cost is minimally more. http://marine-plywood.us/

    Second, go to the Cleveland Public Library and get a few books. "Seaworthiness The Fogotten Factor" By C.A. Marchaj "Yacht Designs" By William Garden. "Buehler's Backyard Boat Building" by George Buehler. "The Nature of Boats" By David Gerr. That would be a start.

    And go bug these guys. http://www.cabbs.org/
     

  15. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    Excellent points... one more..


    If you think building a boat is easy... Build the dingy first, about a 10 footer. When you can build it to your satisfaction and it works properly- build a 20 footer, when that works build a 30 footer... etc... You will find a huge difference every 10 feet. A 50 footer is a ridiculously hard challenge even for experienced boat builder to build on budget or time. Their budget is at least $75k just for the hull. We are not trying to discourage just help be realistic as to what it involves.

    This reminds me of the story of the guy on a deserted island that kept praying for help from God to send him a rescue boat. God sent him a helicopter, dropped him a radio, etc... Finally God got mad at him and said, "Dude are you dumb or something", The guy answers, " I was waiting for the rescue boat".

    Buy a boat hull - save your time and money for everything else...
     
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