20 Aluminum Boat Build

Discussion in 'Metal Boat Building' started by Gnohk_Tad, Feb 25, 2018.

  1. Gnohk_Tad
    Joined: Feb 2018
    Posts: 35
    Likes: 0, Points: 6
    Location: NJ

    Gnohk_Tad Junior Member

    Ok it's terrible but why ? Please elaborate
     
  2. Ad Hoc
    Joined: Oct 2008
    Posts: 6,971
    Likes: 912, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    far too much to go into and would only lead to an endless stream of yet more Qs...

    However, just image you have 2 plates forming a sandwich, a composite. Whilst the periphery is welded, what is connecting the two plates internally?...and then what is the space or 'gap' that is called in other situations if it were a solid piece of ally...a void..or...a crack awaiting propagate! It is terrible on so many levels it is hard to know where to start...but it is your choice.
     
  3. Gnohk_Tad
    Joined: Feb 2018
    Posts: 35
    Likes: 0, Points: 6
    Location: NJ

    Gnohk_Tad Junior Member

    Before sandwiching the plate, it was welded together and re ground to allow the two plates on the outside to lay flush. Then fully welded around the keel plate. The two plates sandwiching the keel together was placed there in the event the original weld connecting the keel failed. Normally only one plate is used as support for this type of joint, but I used two.

    By the way what is the correct way of constructing the keel by the way?
     
  4. Ad Hoc
    Joined: Oct 2008
    Posts: 6,971
    Likes: 912, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Without knowing what your design plans show and call up for the structure...not easy to answer.
     
  5. Gnohk_Tad
    Joined: Feb 2018
    Posts: 35
    Likes: 0, Points: 6
    Location: NJ

    Gnohk_Tad Junior Member

    For the keel the plan called for one backing plate to be used to help support the keel where the two sections are welded together. I used two just in case :).

    Yes I deviated from the plans by adding two instead of one. Is there a negative effect by using two?

    If you had two pieces of plate to join together for the keel, what is your method of choice ?
     
  6. Ad Hoc
    Joined: Oct 2008
    Posts: 6,971
    Likes: 912, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Im not sure I fully understand your question.

    Can you provide a sketch of what you mean, for 100% clarity. Otherwise we may end up going off on different tangents.
     
  7. Gnohk_Tad
    Joined: Feb 2018
    Posts: 35
    Likes: 0, Points: 6
    Location: NJ

    Gnohk_Tad Junior Member

    Sure I'll draw up a sketch , but remember 5 post back you had strong opinions about the third picture (keel) being constructed wrong and gave me a hard time about how I constructed it
     
  8. TANSL
    Joined: Sep 2011
    Posts: 6,625
    Likes: 444, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Try something similar to the figure. This solution is designed to join reinforcements to a plate but it would also serve to join two plates.
    Snap14.jpg
     
  9. Gnohk_Tad
    Joined: Feb 2018
    Posts: 35
    Likes: 0, Points: 6
    Location: NJ

    Gnohk_Tad Junior Member

    Good idea, updates for to today.

    Did some grinding to allow aluminum angle to fit flush frames. The cross bars you see here help stiffen the frames but primary purpose is to add support to the interior floor.
     

    Attached Files:

  10. Ad Hoc
    Joined: Oct 2008
    Posts: 6,971
    Likes: 912, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    G_T

    I applaud your efforts. My welding is rubbish..but im not a welder!
    But, sorry to say, with ecah picture you post, you're not painting a very good picture of quality at all. The first image...wooaah....!!!

    I will bow out..as im sure my comments will make you paranoid. Since i come from a very different background and hence very different level of quality control and acceptance standards, Class builds, not home builds.
     
  11. Gnohk_Tad
    Joined: Feb 2018
    Posts: 35
    Likes: 0, Points: 6
    Location: NJ

    Gnohk_Tad Junior Member

    Anyone interested in this boat build just let me know. It turning out better then I expected. Estimating to be completed in April :)
     
  12. Gnohk_Tad
    Joined: Feb 2018
    Posts: 35
    Likes: 0, Points: 6
    Location: NJ

    Gnohk_Tad Junior Member

    Hey Adhoc dont forget I am just trying to build a boat that floats and maybe last 5 years. I'm not trying to build a spaceship.
     
  13. Barry
    Joined: Mar 2002
    Posts: 1,426
    Likes: 229, Points: 63, Legacy Rep: 158

    Barry Senior Member

    This from Gnoch-TAd

    What quality are you talking about ?
    I would imagine the weld quality. The stops show craters which can lead to cracking. It does not appear to be cut back before the next weld. These are generally accepted welding
    practices so you don't get discontinuities etc.


    You never even answered my question on why the keel was built wrong.
    The explanation for this, again under generally accepted engineering practices, GAEP, is that when you join pieces of material , you try to minimize the areas where you can introduce stress concentrations,
    or "hard spots" Tansls solution, and proper fish plating is another, would have been a better practice. Will you have problems, probably not, only because you will have a factor of safety inherent in the build that will minimize problems. But if you were an engineer/naval architect designing a boat, whose income, reputation, and adherence to sound principals, you would not have done it like you did.



    Its great that you come from a background with "quality" , but I'm sure 99 percent of the people on this forum are home builders. Most people don't care about getting it perfect. The real goal is to build a boat and if it floats lol. Most of you guys just sit around and respond to post, but funny thing is you probably never even try to build a boat. All you guys do is recommend YouTube videos and buy books to read. I can tell You guys have no real boat building experience at all, it's really sad to see.

    I would like your crystal ball where you have somehow have deduced that the contributors have never built or designed a boat. If you have followed the forums or even gone to the
    search forum, upper right side, and enter aluminum boat building etc, you will see contributions that would have helped you out with your project. While you suggest that "you guys have no real boat building experience" you have admitted that this is your first build and first time welding. Books to read, yes some were suggested as they are written by people who have had a lot of experience building boats and several are a few hundred pages long. Providing input to you is difficult without, well, writing a book. Re aluminum welding, it is a quite different from steel welding, less forgiving, to failures than steel


    I really question if you guys even ever built a boat or do you guys just sit around all day giving generic answers on this forum and just hating on other people's builds.

    I don't think that anyone hates other peoples builds. All the replies have tried to provide information to you. If you do not believe the inputs, why are you on the forum? To criticize those
    who mainly are trying to help? And many of the contributors here have built boats, many for a living and some with their own naval architect companies. and you?


    Also I don't get Paraniod , all it does is stop progress. I'm going to countinue to build this thing and not worry about what you say bc it so obvious you have no idea what you are taking about.



    You guys just read random stuff online and regurgitate it on this forum. So sad to see
    What is sad to see is your response to people who are trying to help you. For free, with hundreds of years of cumulative experience.

    One comment about "most people don't care about getting it perfect"
    Maybe, but getting it right is a goal. When you get caught in 6 foot waves, with your family aboard and having to get back to shore, you might reconsider your comments.
    Getting it right costs about the same amount of money as getting it wrong, initially.
    Getting it wrong, well the cost can be much larger.

    And hope that when you ride in a Boeing, that the engineers got it almost perfect


    One last comment
    The hull is only one part of your build. Knock books all you want. Assume, that you might spend 30,000 or more on the build by the time you get it finished and over a thousand hours of time.
    For about 400 bucks you can buy a set of standards from ABYC. I expect that it is 400 pages in length but it will give you guidance on things that will be difficult to get from forums. Type of wire, type of hose, electrical considerations, especially fuel tank installation information, and the list goes on.


    Re fuel tanks,
    Hate to be rude, but get a ticketed welder to tig weld your tank. Your welding procedures are not up to the quality required from the pictures that you have shown.
    As the lives of your passengers will rely on having tanks that do not leak, please take this piece of advice.


    View This Thread
     
    Last edited: Mar 13, 2018
  14. Ad Hoc
    Joined: Oct 2008
    Posts: 6,971
    Likes: 912, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    What he said...
     

  15. Gnohk_Tad
    Joined: Feb 2018
    Posts: 35
    Likes: 0, Points: 6
    Location: NJ

    Gnohk_Tad Junior Member

    Thanks for the clarification .... again if it floats I'm happy. Also only a idiot would take his family out in 6 foot seas in a 20 foot boat.

    Again not trying to build a rocket ship, just trying to build a boat guys.
     
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.