Self Design.

Discussion in 'Multihulls' started by redreuben, Jul 31, 2013.

  1. redreuben
    Joined: Jan 2009
    Posts: 1,788
    Likes: 123, Points: 63, Legacy Rep: 349
    Location: South Lake Western Australia

    redreuben redreuben

    It seems that many types of people have designed boats, the knowledgeable sailer, those with a good eye and drawing skills and those who just stand up the frames and design as they build. And of course the fully trained professionals.

    Reading the posts here people who are contemplating their own design are warned off by the experts and others to either buy existing plans or engage a professional.
    But many good boats are designed by amateurs, what if there just isn't a design that meets your needs and you can't afford a custom design ?

    Is it feasible to say make a model of what you envisage, take the lines off it and then have a professional tidy up the lines and balance out the foils and sail plan ?
    Would this go some way in ameliorating custom costs ?
    Would a professional take this on ?
    I would only consider this approach for boats under 9m.
    Look forward to your thoughts.
    RR
     
  2. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 341, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    A model, partiularly an rc model, is a very good way to test some aspects of your design and to see if it looks as good on the water as you want it to. If you do it carefully a good NA might appreciate it but , for sure, you will learn a lot.
    RC models have been used by many designers to try out concepts before building full size. Build the largest model you can....
     
  3. redreuben
    Joined: Jan 2009
    Posts: 1,788
    Likes: 123, Points: 63, Legacy Rep: 349
    Location: South Lake Western Australia

    redreuben redreuben

    I was thinking 1/10th ? Being a metricated man !
     
  4. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 148, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    If you an afford to build a 9 m boat, you can afford a properly designed plan. Surely you can find something close to what you want in existing plans, that would save a lot of design cost. Consider how costly a major design mistake would be.

    what is it you are considering building, what kind of boat, construction methods, etc?

    If you want to learn how to design boats so you can do your own, there is nothing stopping you. Lots of people do it, sometimes they even made some decent boats, likely you could too. But it is a false economy if you think it will save you money. Several years of spare time yacht design study could be done and you could design a decent boat, but you would do it just for the intellectual challenge and joy of learning how do design a boat, not because it saves you money. That time invested in learning how do make proper and safe plans to get a boat you will be happy with would better be spent building the boat or with a second job earning extra income to build it. consider that you will get your build started a year or two sooner than if you decided to learn how do design boats first and than get started. Only do the design yourself if you really want to learn how do design boats as a goal in itself, not because you want to get something different or think you will save money.

    I have 30 years experience as an engineer in aerospace, automotive, structural design and some marine design, professionally educated and know a lot about ship design, but I do not think I would design a boat that large on my own. I have also built over 20 small boats of my own design, mostly as experiments and I take the good with the bad, expecting occasional mistakes. But none were very costly to build so I was not concerned, they were just fun experiments in boat design. There is a lot to know to make a boat larger than a dingy or sea kayak, and with that much time and money invested in a build on something larger, I would want someone who specializes in yacht design to at least look over my ideas, and give me a dope slap if I am doing something wrong. I am saying this as someone that likes to design my own boats.

    Here is an idea that might get you what you want: find a current design that is similar in size, type and construction method that you want, and develop some ideas and drawings around it about what you want, and than contact the designer and have him or her go over your ideas. And than pay the designer to develop a full set of plans as a variation of their existing design. This will keep you from making a very costly mistake, and likely get you something that you want faster and for less than doing a new design from scratch.

    If the navel architect has a good reputation, than if and when it comes time to sell the boat later, it will have more resale value than just something an amateur put together. The cost of the custom plans would be an investment in the finished value of the boat, and it likely will save you a lot of construction costs in wasted materials and mistakes during the build. A good designer will not only make you a more valuable design, but will also likely save you more in construction costs than their fee.
     
  5. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 341, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    --------------------
    2m model would be better for a 9m boat...
     
  6. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 148, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    if you are going to go that large might as well go 3 meters and get a man carrying dingy out of it. More fun to test too.
     
  7. kiwi_bob
    Joined: Aug 2011
    Posts: 18
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: New Zealand

    kiwi_bob Junior Member

    Go for it

    All depends upon your risk profile and why you are doing the designing. The fact is that building a boat doesn't make a lot of financial sense anyway so, if you're feeling creative and have the confidence, go ahead and design something unique. If you are building a racing boat and get engineers and pros involved, your boat will probably not break but may be too heavy (compared to gung ho amatures) as pros are going to be conservative and don't want you coming back to them with a broken boat. There are also shades of grey here - you can buy a design and pervert/modify/pimp it too - the original designer may get huffy but will probably get over it, esp if you start scoring some good race results and some of your ideas may get incorporated back into the core design - it happens a lot.

    I'm coming from a racing angle here - for a cruising boat or if you see it as an "Investment" (even professionally designed and built racing boats are about the worlds worst investment) then another set of priorities may apply.
     
  8. daiquiri
    Joined: May 2004
    Posts: 5,373
    Likes: 252, Points: 93, Legacy Rep: 3380
    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    In short - if you can't afford a designer you probably cannot afford a boat too. Because the cost of building a boat is several tens of times higher than the designer's fee. ;)

    It can be done, of course, but it has to be a two-way exchange of ideas with the designer. Your design will very probably have deficiencies which will be noted by the experienced eye of the professional. They will be discussed with you and a solution shall be identified and agreed by both parties.

    What you can't expect from any serious designer is to have a boat with evident design errors accepted as it is and just signed off without objections. Not even if you are the guy who signs the check. Maintaining a good name is much more important to a serious designer than receiving a check for a single job. A check is a short-term benefit, a good name is a difference between sinking or staying afloat in the business. ;)

    Cheers.
     
  9. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 148, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    I have another thought on your idea of building a model first. what do you hope to learn by building a model? If you do not have something to compare it to than it seems to be a meaningless exercise, how would you know if it performs better than a conventional design unless you have a conventional model, at the same scale, to compare it to? Do you expect your ideas to make the boat faster, easier to handle, safer, carry more passengers or what? what is your baseline? What is it you are trying to accomplish with the new design?

    And I do not think having a professional design you a boat from your model will save you much, they still have to develop full size plans, all the structural details and scantlings for the full sized boat. These do not scale well from your model and have to be developed for the forces on the full sized hull. You likely will find an NA to do your design work, particularly if you have starving NAs around (which is likely), but all he would have is a scaled hull to work from, little better than a sketch. Most of the work is not so much the shape of the hull, but developing all of the other details, structural design, rigging, appendages, etc that go with it.

    So I suggest you either do it all yourself, or find something similar and have the designer incorporate your improvements into his design.
     
  10. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 482, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Because of some seemingly quirky physics, models don't offer as much as you'd think to real live examples. If you look at a pond yacht, you'll quickly notice it has a huge rudder and fin, compared to a similarly shaped full size yacht.

    No self respecting designer will work from a clients drawings or models. They will take styling clues from these, but that's about it. This is simply because the provided information has to be checked, all the way around the spiral. Nothing can be assumed correct, so every aspect is questioned. This is especially true of this type of work, whereas on the other hand, if the design was the designer's own development, some things could be assumed, from prior experience with similar hull forms or rig types and the process is quicker and cheaper.

    Simply put, if you force a designer to use your models or drawings, most will bug off, unless you can prove the validity of the choices, made around the design spiral. Anything short of this, causes the job to take a lot longer (validating someone elses work), so most just tell you to look for someone else on this project.

    Look at it this way, if you brought a design for a new house, to an architect. He'd have to check the validity of each and every stud location, every header, every sill plate, etc., but if it was his own work, he'd already know the sills, studs and headers are designed properly, so much of the work can be assumed proper for the loads involved, saving him a lot of time and effort. It just costs a lot more to use someone elses work as the basis for a new design, then just starting a whole new designed based on a comprehensive SOR from the client.
     
  11. DCockey
    Joined: Oct 2009
    Posts: 4,945
    Likes: 463, Points: 83, Legacy Rep: 1485
    Location: Midcoast Maine

    DCockey Senior Member

    My guesses at answers to your questions:

    It should be feasible to use a model as a starting point for a professional to design a boat. Emphasis on starting point. The model could serve the same role as sketches and photos of other boats do in helping to communicate what the client wants.

    There is much more to designing a boat than tidying up the lines and "balancing out the foils and sail plan".

    Unlikely. Even if the model represents a well thought out, balanced and coherent concept there still will be time required to understand and evaluate the concept and translate it into the designer's ways of working. And that's just to get started.

    A more effective way to reduce the cost of a custom design would be to start with one or two of the designer's existing designs.

    Would probably depend on how interested the professional is in the concept, how they evaluate the person making the request as a potential client, and how much other work they have.
     
  12. redreuben
    Joined: Jan 2009
    Posts: 1,788
    Likes: 123, Points: 63, Legacy Rep: 349
    Location: South Lake Western Australia

    redreuben redreuben

    My main motivation for using a model is to use the Gougeon's methodology of using birch modelling ply to represent full scale plywood sheets.
    The boat I have in mind would be 7.5-9 meter hash up of a Crowther Buccaneer and a Horstman, a modern sleeker Horstman or a fat Buccaneer lol.
    Basically I feel the Horstmans are are bit old and could use a modern revision and the current crop of contemporary trimarans are too performance orientated for my needs.
    Searunners ? Nuh sorry don't appeal, at all !
     
  13. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 341, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Just a bit on the model side: some of the most well known designers and innovators have used RC models to test their concepts including:
    1) Dr. Sam Bradfield, who used a 5' model to test foil placement and rig placement for his 40' SKAT. He also discovered a 1:1 correlation in the model foils area as compared to the full size.
    2) Yves Parlier with his planing catamaran,
    3) Bill Burns for testing models using CBTF(canting ballast twin foil) technology,
    4) Hugh Welbourn for testing early ideas for DSS(Dynamic Stability Systems).
    5) Greg Ketterman to develop his foiler concepts.
    And there are many more......
     
  14. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 482, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    It's one thing to test design elements on a model, typically with focus in a specific area, but another to use it as the concept for a full design. We all use models of some sort for aspects of a design.

    You can use scale plywood models to test "buildability" like Ian and Jan have done at West, but these were truly experienced builders and designers, with much understanding of the engineering a hydro portions of these projects.
     

  15. El_Guero

    El_Guero Previous Member

    OK,

    Few decent engineers will take over someone else's mistakes - that is a design issue prone with problems.

    First, the time it takes to 'understand' the other person's work, can normally allow the engineer enough time to design a better design model from scratch.

    BTW, this is design model, not necessarily a physical model.

    But, some engineers will accept the challenge, if the idea intrigues them, enough. Like trying to get a corn kernel from between your teeth at the theater, it just will not leave you alone.

    Having said that.

    You need an engineer with products you already like.

    The cost to have an engineer take what you like and add it in would be much more valuable to you.

    And the overall cost of your project would be MUCH less than building two or three dream boats and then having an engineer look over your dreams.

    BTW, it typically costs as much to have an engineer to look over and approve a dream as it does to build the dream with you.
     
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.