Amateur design insulting to pros?

[Scot McPherson]

chebacco is popular

 

[Todd Beckett]

 

[Todd Beckett]

This is the blue moon I built, ( first Try at boat building) admittedly the cabin is pretty square but I think it looks OK with the porthole & sliding cabin top.

 

[M&M Ovenden]

Murielle (My wife and one of the M's..), designed and built our boat. Lots of research ,reading and work, but not impossible. If there is a stock design that meets 90% of your criteria I'd say just go that way to speed things up. We haven't launched yet, so the jury is still out

Mark

 

[Ilan Voyager]

Build and enjoy. Just use common sense. Remember there were no naval architects building for the Vikings, just smart carpenters who studied out the problems. Ask questions and welcome to the forum!

Youŕe mistaken. Vikings had master builders who were also naval architects/engineers with an enormous experience. Very empiric, the bad designs and or poorly built boats would eliminate by themselves sinking and drowning the crew. The builder would be eliminated by different means as hanging or beheading. That should be applied to bankers nowadays, and the financial system will improve..
That behaviour pushed to a quest of quality in the Viking context, as everybody knew that the boat made by Olaf was a piece of s**** while seeing his smelly rotting corpse devoured by the crows. Instead Thorsten, master builder, heir of six generations of master builders, 25 years of experience of making the finest trading and raiding boats was a prosperous guy. They were naval architects and good ones.
I had the honour to know and to have worked for two master builders, and they knew perfectly how to design a wooden classic fishing boat. Alexandre Tertu designed and built fishing boats until 120 feet long and 700 metric tons in classic wood. Asked to design and make a 15 m sail yacht, he answered I can build it but the design has to be done by a NA of sailing boats, in this case Eugene Cornu. More you know, more you are cautious...
To give an advice to Sobell. Theoretically as retired NE Im very able to design a retro 20 feet monohull sailboat, but I would prefer to buy a good set of plans, complete , well detailed and to pay the small price compared to the overall cost. There are plenty, and the choice is vast. Many hours are saved. I'd prefer to keep my mind focused on the building with the best standards with my personal touch.
How to overbuild? easy. A NA knows that a 1/2 plywood with 3/4 by 3/4 stringers will do the job safely. An anxious amateur will use a 3/4 inch and stringers 1.25 by 1.25. Besides the weight and cost, he will discover that the plywood refuses totally to bend, and that scarfs on a 3/4 are a costly pain to make...

 

[BayBoater]

My name isn't Olaf, and I'm still alive. I recently delivered an 8' "Viking boat" that I designed and built to my small nephew named Torsten.

Before painting I got in it and tested it out a bit. It is big enough for an adult and stable enough that I could turn around in it. It is made with a 3/4" thick solid wood dory bottom and 4mm marine plywood sides and was sturdy enough that it remained unscathed when the wind blew it around my yard a bit. Crash landings through surf pounding a rocky shore weren't part of its design brief, but getting dragged and maybe even blown around the ground at the cottage is expected.

I didn't know this before, but the master boat builder at our wooden boat museum told me that they had to beef up the scantlings of the framing in their banks dory replicas because they ended up getting shaken apart during trailering. The costs of deferred road maintenance offloaded onto the taxpayers. A stitch and glue plywood boat wouldn't have such problems even if the plywood is just 1/8" thick, but would try to get airborne if not strapped down well.

If you find the design process as rewarding in itself, the design homework will not feel like work. By the time I'm ready to build one of my designs I have a pretty good idea how comparable my boat is to the similar designs out there, and I will stick with similar scantlings. When trying something radical I do it with a "low risk" boat like a small rowboat.

For example, I'm working on a boat that will be a prototype in two ways, a new building technique and a new design, both of which are further developments based on what I have successfully completed before. An origami plywood design that will be fastened using a quadruple system of screwing into butt block framing, cable ties, marine sealant and Gorilla tape. This is meant to be a temporary boat; its cheap plywood isn't waterproof and I expect it to last a few years at best, just long enough to teach me about how the shape will behave in a variety of conditions.

I started corresponding with an eminent designer about one of his books that I purchased and sent him examples of my designs. He thought enough of my approach and one of my sail/oar designs to send me an 80 square foot sail plan for free even though I mentioned that I've never really sailed before. That isn't a trivial amount of sail; it will require a 14' mast and a tiller extension for hiking. Needless to say, this boat will be built in standard stitch and glue technique once I'm convinced from a paper model that the shape will come together well. I'm not putting that much sail on anything held together with even a super redundant combination of relatively flimsy fasteners.

Trick is figuring out how many baby steps you need to get to a safe design. The risk goes up with size and speed and the real danger is when people think they can save money and time by designing their own. Even if you save money, you don't save time. If in the end the boat doesn't perform as hoped, then no money has been saved either and a complete amateur might not even know if that would be the fault of the design, the execution, or the unrealistic expectations of the user.

 

[Ilan Voyager]

BayBoater, you have an excellent approach. And the last paragraph is gold.
Yes, there is a pleasure of designing, I have committed a few in fast sport catamarans, 18 square meters and 20 feet raid cats, plus some F40 modified, but you must have a serious amount of knowledge, theoretical and practical even for a simple retro style 20 feet, if you want a good mannered and safe sailing boat

 

[Rurudyne]

The builder would be eliminated by different means as hanging or beheading. That should be applied to bankers nowadays, and the financial system will improve.

For some time now I've maintained that some "professions" just do not have a decent claim for respecting their "credentials" given that it is difficult, sometimes even impossible, to test the soundness of their decisions and proposals until long after they've been gone, at which point it's often too late and the damage is done.

In finances, for example, it is relatively easy to doublecheck an accountant's work as these ultimately rest on the numbers but extraordinarily difficult to check an economist's. As for those who live off of the churn on so-called money products (ways to manipulate money that don't actually produce goods and services) they're even worse.

The same can be said of engineers, doctors, chemists and so many others whose efforts or professional judgments can be reasonably double checked by others just on an examination of the available facts and numbers ... these have great claims for professional credentials where many others, like aforementioned economists or any number of humanities topics (especially the -insert here- Studies sociology phenomenon that has proliferated), just do not.

 

[Sobell]

This is the blue moon I built, ( first Try at boat building) admittedly the cabin is pretty square but I think it looks OK with the porthole & sliding cabin top.

Todd, thank you so much for posting a pic of your Blue Moon build. I'm so excited to find that somebody built to those plans. Do you mind if I ask you some questions about the building process, and the finished boat, and how she is on the water? BTW, I think you did a terrific job! Do you mind if I copy/paste your photos in other boat forums I'm a member of?

 

[alan craig]

Rurudyne, your post above; what an excellent and concise summing up of some professionals.

 

[Rurudyne]

Rurudyne, your post above; what an excellent and concise summing up of some professionals.

Thanks.

More relevant to this forum and thread would be the difference between a NA who for a client may agree to dabble in unusual styling (still fully functional and safe as a boat) and some stylist/graphic artist who dreams up bizarre dysfunctional engineering (like that large flying sailboat).

 

[Sobell]

I've been looking at this photograph. I'm amazed at how many frames there are, and the scantlings. This boat was designed in 1972 or so, and I'm wondering if the advances in plywood and adhesives would allow modifying the plans to eliminate every other frame, and to change the scantlings of the ones that remain. According to the plans, frames are made from 1x2s and 1x4s. These appear to be 1x4s and I wonder if 1x2s could be substituted. Seems to me that widening the available cabin space by 4 inches would be quite an increase.

Blue Moon inside Cabin | Boat Design Net https://www.boatdesign.net/gallery/blue-moon-inside-cabin.26120/

 

[troy2000]

There are plenty of well founded designs that are likely to provide exactly what you're looking for, just needing some aesthetic upgrades to suit your whims. Designing a 20' sailboat isn't a great feat, though you sure can build an ill handling beast if you don't know what you're doing. Most of these older designs can be converted to taped seam or other build type, with some education or help. Pick up the book "Elements of Boat Strength" to get a handle on some of these conversion processes and a general idea of what might be involved with your self designing a fresh new boat.

Find a design that is close and make the appropriate modifications, so it suits your needs. Try to avoid reshaping the hull other than a 10% - 15% straight stretch (if desired) and you'll probably float upright come launch day. Screw with the hull shapes and rig balance very much and you might have extreme difficulty, trying to quantify any changes and modifications, to address issues (there's always issues).

Lastly, yes there sure is such a thing as overly or too strong. A perfectly engineered structure will suddenly, explode when it reaches its failure point. This means all the elements of the structure were sized appropriately for their loads, no heavier than necessary and contributing equally to the whole. If an element is "too" strong, it will transmit higher loading to less substantial surrounding elements, forcing them to tolerate more than they can take and now you have an often difficult to diagnose, localized failure.

Are you familiar with Oliver Wendell Holmes Sr.'s poem,
"The Deacon’s Masterpiece
or, the Wonderful "One-hoss Shay":
A Logical Story"?
It's about a chaise carriage that was built with no weak points: each part was as strong as every other part. It lasted a hundred years, and then...

"All at once the horse stood still,
Close by the meet’n’-house on the hill.
First a shiver, and then a thrill,
Then something decidedly like a spill, —
And the parson was sitting upon a rock,
At half past nine by the meet’n-house clock, —
Just the hour of the Earthquake shock!
What do you think the parson found,
When he got up and stared around?
The poor old chaise in a heap or mound,
As if it had been to the mill and ground!
You see, of course, if you’re not a dunce,
How it went to pieces all at once, —
All at once, and nothing first, —
Just as bubbles do when they burst.

End of the wonderful one-hoss shay.
Logic is logic. That’s all I say."

Poem: The Deacon's Masterpiece, or, the Wonderful One-hoss Shay: A Logical Story http://holyjoe.org/poetry/holmes1.htm

 

[jehardiman]

When a total amateur attempts to design a boat (say, a sailboat < 20 feet), or a tiny houseboat/shantyboat -- a box, basically, on a scow hull or pontoons), is that an insult to professional naval architects and yacht designers who have been properly educated/schooled/apprenticed, etc.?

No, what is scary is when a professional tells an amateur that they need to correct something to prevent loss of life, and the amateur thinks that they know better. Really, anyone can build as boat, and I will venture to say that 75% of boats built and used are built by people who do not have "school recognized" ability. That's OK. What really irks me is when someone comes to this forum looking for approval and doesn't find it, then begins to disparage those who have gone through all the classes. Physics doesn't care if you think you are correct.

 

[Ad Hoc]

What really irks me is when someone comes to this forum looking for approval and doesn't find it, then begins to disparage those who have gone through all the classes. Physics doesn't care if you think you are correct.

Yup..those searching for their own like minded echo chamber, and dismisses anything else, because it doesn't align with their planetary signs on the day!

Engineering has not emotions...just facts.