How to Design a Boat from a Half-Hull to the Line Drawing
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- เผยแพร่เมื่อ 26 ก.ย. 2024
- Designing a boat from a half-hull model is covered in full in this episode of the Art of Boat Building. Boat Builder, Bob Emser, discusses Nathanael Herreshoff's old master way of designing a boat straight from a wooden model. He shows us Capt. Nat Herreshoff "Offset Measuring Instrument" and his modern replica of one. Made from off the self materials Bob demonstrates how the offset device is use to take off the body plan measurement.
Bob and Steve Denette have discussion on the layout of the new tender Victoria.
We also go on a field trip to the Wooden Boat School where Paul Gartside, Naval Architect, teaches about spline weights. We then see the production and casting of the lead spline weights (Ducks) by a fellow design class mate, Matt Moeller.
All is finished up with the line drawing being completed.
“If you’re going to make it, make it beautiful.”
Bob Emser
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This is just about the best TH-cam channel on boating. Sharing such knowledge is so rare, but wonderful.
Wow, thank you!
As a 3D mechanical designer who has operated SolidWorks for over 15 years, I immensely enjoyed this video! I began my drafting education back in the days when we still learned on the drafting table with a T-square, parallel bar, or drafting machine. I couldn't help but think through the process of creating this design in the 3D realm while watching you work on the board. Bob, you do FANTASTIC work! Thank you for sharing that with us!
Thanks Craig!
Fully agree! I was a draftsman prior to my engineering profession, so I learned to use a drafting board, write neatly in block letters, and so on. Not a bad start to a professional life as a snot-nosed 18 year old kid!!
What a great video, Bob! I've met many people who will tell me they have found half-hull models in old houses or barns, and have explained to them that what they might have is THE DESIGN, and not just a decorative nautical carving. I knew this in theory, but not how it actually worked, per se. Next time someone asks, I've got a resource to share. Cheers! -Annie B
Thanks Annie!
I had made a whole board of them, scaled out for 1"/1' scale. Somehow they got thrown in the trash when someone got angry for some reason---I think, although I would laugh uproariously were I to find out that someone had bought them for decoration.
There's nothing like sitting down and drawing up some plans for something.
Its just so relaxing.
And Steve asked Bob to build Victoria why? Here's the answer. In video. Excellent! Precise and beautiful. With functionality being key.
Thank you, Bob, for the simple, to the point lesson on lofting. You made what I used to think of as black magic much easier to understand. Thanks again
It is fantastic to me that you can do this with a fairly minimal amount of mathematics! Thank you for showing this.
Side remark: It is very nice, hearing the crickets in your video. Sitting here on a rather cold, dreary evening, it makes the summer come back at least in my mind.
This was very insightful, I have always had a problem trying to understand how this was done. You have made it a lot more clearer, will I still need to take a class on this ...oh boy yes but I should not be swimming so hard when I do. Thanks for sharing Bob.
As a retired sculptor from General Motors, and also a boat builder and a sailor, I really appreciate the way you have explained the lofting process. It is identical to the same process we use in the design center to model a full size clay model of an automobile. Of course our equipment is much larger. You’re doing a fine job of explaining how the process works and it is very understandable for anyone who has not done it. Thanks a lot for what you are doing. It bring back a lot of memories and it’s fun to watch.
Spline fitting with ducks…a new insight to the phrase “getting one’s ducks in a row”. 😊 Thanks for sharing the details.
Another fascinating video, Bob. Also, I'm the proud owner of a "The Art of Boat Building," and "Long Live Victoria" T-shirts!
Happy Fall!
My partner did an apprenticeship in naval architecture with the Royal Navy, then went onto be sponsored to do a Naval Architecture degree. He has worked on many projects in his working life but still recalls the time he spent as an apprentice making a small tender from line drawing, lofting, making forms etc etc right through to the finish and launch. It is fascinating to me to watch the process on video. My partner, now retired from many years working on moorings and stability issues in the North Sea oil fields, would love to do a job like this tender once more.
Hey Bob,
Just thought I would mention that I made mine by carving a wooden pattern and casting high heat silicone moulds.
So wonderful to see your ingenuity in action.
I too would like to acknowledge Matt’s Drafting whales. When you unwrapped them my first thought was “what a great colour choice!”.
So funny, red is my favorite color, but as I imagined a critique, I was sure people would say it is distracting to the task of evaluating the fairness of the spline-paper color would be best. Classic case of over-thinking.
Great video, Bob. Nice to see, Paul's cameo too.
I like your precision 3D measuring instrument. I already have all the components necessary in my shop and never knew it.
Thanks for sharing.
I designed the very first boat that I built, but in full size with no lofting, no plan, nothing. It floated but was generally a disaster and I swore that I would forever more, leave designing to the pros. I may change my mind! This is quite inspiring! I want to go take Paul’s class. Good stuff Bob!
Thanks Chuck! Paul’s class is awesome I think you’d really enjoy it.
Bob, I'm not an engineer like many of your fans, but a humble Acorn To Arabella fan, so I say, how inspirational it is to follow what you do, how you do it and the support you have of your followers. I'm so glad you support Steve.
Great tutorial on a subject that was a mystery to me. As always a pleasure to watch you work. Cheers!
I am very happy and satisfied with your videos class. as I am a naval designer and model maker, this video helped me a lot. the resourcefulness in the explanations They are very detailed. Thanks.
about 5 months late !! when viewed from above the "tab" / "pointer" really brings to mind a Duck Bill. Even the color of the wood duplicates a duck build. I also see a resemblance to a Whale shape. I spend too much time on you tube but there is so much to see "learn". I have watched all of the Arabella and tally ho videos. I have already too many hobbies, but I do mess around with a bit pf wood working. Just restored an old Craftsman Joiner and working on a Craftsman turning lathe, probably from the 1950s. I have watched your other boat videos and will continue to "catch up" on Victoria.. Thank you for sharing.
The suspense thickens
Quite interesting, particularly the “duck” tale. Very nice set created for your project.
Clear and concise explanation of method.
Thanks Bob.🙂
Exciting stuff! Thanks for sharing. 🇨🇦
The phrase "Getting your ducks in a row" comes to mind.
That's awesome of Pat being able to volunteer his time in scraping off that old paint off all that wood ..love your half hull measuring device you made up out of a speed square and a digital caliper and a ruler to get your offset measurements. That's a good idea Bob. Whatever works right?
Great video Bob. Thanks for sharing.
Amazing work! But I just keep wondering how much easier all that would be with... (no, not with computer, well, yes ;) ) ...but with millimeters! :D
The answer is at 1:17 I'm more interested in the process than how fast it can be done. I've used the Imperial System of Measurement my entire life. Most all of the boat plans I own are in inches and feet as well as the Table of Offsets. The metric System has many benefits! However, for me too mentally, or with a table, convert measurements would not be faster or easier.
Thanks for watching.
Bob
Depends on which system a person is most familiar, and how long they have lived with it. The imperial system is the standard in maritime design in our part of the world. Conversion would be a whole lot of extra work. Not to mention, most tooling and materials available in the U.S. is imperial, not metric.
I find this stuff kind boring but I recognize the importance of this knowledge set & am glad to have some experience with it even if it isn't the most riveting thing to me.
Good job & the Half-Hull models are beautiful works of art
I love this channel! Just a thought on an alternative approach to drawing your curves - instead of using lead weights, as beautiful as they are, would we not consider placing a metal sheet beneath the drawing and use neodymium magnets? You could keep the points of contact incredibly close and at a high resolution, while also staying out of the way so you can draw freely. Just a thought…
Interesting, I’ve never seen or heard of that approach. I don’t see why it wouldn’t work. Fortunately for me Matt gifted me the spline weights so this is what I’ll stick with.
Thank you I’m so happy you’re enjoying the channel.
Thanks for watching.
Bob
Great video as usual Bob. I'm curious about one thing and it's likely because I don't understand something: It seems to me that you could have taken your initial table and just put it in a spreadsheet then multiply by the scale to convert your measured dimensions to the full size dimensions which, if I understand correctly, would have given you the same results as the Herreschoff device.
@@ralphgesler5110 I know that. The difference is that, as Bob stated, the Herreshoff device provided the full size dimensions where Bob's only provides the model dimensions that need to be converted to full scale measurements on a lofting floor. Putting his measurements in a spreadsheet and doing the conversion there, I think, would allow you to go straight to the lofting floor. I think it would make the small scaled drawing unnecessary.
@@erickuehne4194 Mathematically scaling the original boat would make the new boat smaller abreast as well. Steve wanted it shorter fore and aft, but not narrower abreast. So, this was the path to take to lessen the length without making the tender skinnier. An overall spreadsheet calculation would reduce all aspects of dimension.
@@thomasarussellsr I don't know how you drew that conclusion. First, I was just thinking that this as a possible way to avoid having to create a scaled line drawing. Second, it is a suggestion for technique and is independent of any particular design. And I'm aware of the dingy's requirements. Third, I'm not suggesting he takes and existing design and extrapolating from that but using the half hull model for the actual design and going from there. As there are no half hull models for the 8 and 10 ft designs I'm curious as to how you thought he would pull spreadsheet data from them.
This is a very interesting hobby . I'm building a RC logging tug boat in 1/16 scale. I could use my FreeCAD program but doing it the hard way is more fun.
So I clearly missed something: didn't you already have a line plan, that you built the half-hull model from? Fascinating video; I particularly admire your Home Depot Herreschoff device.
Victoria is based on two Atkins plans, one shorter, and one longer, than the tender needs to be. So neither line plan suits and this is why Bob is taking us through the whole process.
Victoria is being designed as a modified Atkins boat between the sizes of two similar boats that Atkins designed. Plus the requirements mentioned in this video and a couple others mentioned in other videos on both channels require changes to the plans that neither boat's plans include. So Bob is taking a bit from both plans and meeting somewhere in the middle and adapting/redesigning to meet the laid out criterion Victoria must meet for A2A's tender. Basically designing a whole new boat. So, "back to the drawing board", so to say. The half hull just took the over-all shape that Steve liked and then Bob adjusted the stations to fit requirements as needed. The old drawings, after the redesign, are basically worthless for the newly designed boat to be built from.
Wonderful instructions! But please look again at your cwl aft. Between stations 9 and 10 this line seems to be a bit flat. Could it be that you ended the line a bit too far aft? Love your channel!
Seeing the way the “ducks” work with the batten (especially for long curves) makes me wonder if this is the origin of the expression “to have your ducks in a row”.
That looks falimar, I took the layout class with Greg Rossel.
There is not many videos on this. Thank you, this is exactly what I was looking for. But how and where would you find plans?
The Wooden Boat store is a good place to start. go to www.woodenboatstore.com/ and click on plans.
Thanks for watching
Thanks.
Cool video. We still have some ducks on the drawing boards at Boeing, for the airplanes still in service that have not been converted to digital drawings/loft lines/etc.
Since I’ve been working there since 1988, when an early career engineer sees a duck, they need an explanation as to their purpose. I think I’ll push them to this video, because you show they’re used (which now is quite infrequent in aircraft design).
very interesting. I wonder though if a boat designer cannot just draw the lines on a plan and go from there. You should be able to visualize the boat's shape as well as with a half model. Do I miss something?
Also, wouldn't I build a 3D model on the computer to fully appreciate the lines?
Did Herreshoff made any calculations to improve the sailing speed of a boat or is it "just" experience?
Hi! I work in a shipyard and do a lot of reverse engineering of linesplanes for hull damage repair.
My mentor and available lecture have prescribed that the station marks indicate major changes in the hull shape. You are approaching it a different way, where did this method come from and how do you integrate major plane changes in the fabrication if not by stationed sections?
Really great content. It's great to see the Herreshoff method. Head's up, I see a very minor error in your placement of the waterline at the transom. The LWL should intersect the centerline at station labeled "S1", and as drawn, it intersects the transom at the top of the transom. Any chance your friend from the class wants to make more of those drafting ducks ;-)
Hi Matthew, Yes, I caught it while editing. You have some keen eyes!
This is the maker of Bob’s ducks. I already have an extra ten more like his. How about I mail them to you with three conditions: 1. You are a patreon 2. You donate $350 to the WoodenBoat School Scholarship Fund (tell me if this is a hardship for you), and 3. You live in the United States (flat rate USPS shipping would be on me).
@@matthewmoeller821 That's awesome of you. No money into your own pockets, but supporting the school. As a matter of fact, money out of your pockets for material, supplies, time, shipping...
You're good people!
I am a big fan of the Paul Gartside!⛵️
Me too!
I have a question to ask you! If you were to build a sailboat with an engine, how would you know the exact location of the waterline? Do we need to calculate the weight of the entire ship and calculate the displacement based on this weight, and then obtain the waterline height of the entire ship based on the cross-sectional area and displacement of the bottom of the ship.
So, I may have missed something - was the half-hull model made from a line drawing as well? Did you go from line drawing to half hull model to line drawing?
A viewer recently answered that question.
"Victoria is based on two Atkins plans, one shorter, and one longer, than the tender needs to be. So neither line plan suits and this is why Bob is taking us through the whole process."
In addition, as you could see by my conversation with Steve, The are many unique parameters to the design of Victoria. This is why I've essentially started from scratch.
I hope you are enjoying the process.
Bob
@@TheArtofBoatBuilding Ah, yes, I had forgotten that Victoria was a hybrid of two plans, that explains it. Thanks, Bob!
@@captainpanda5533 A hybrid of two plans, plus adaptations of the stations for specific needs.
How were the offsets taken off the half model by those working without Herreshoff's device? You could saw the model up down the station lines...?
Cutting up a half-hull would be a way to do it.
Not to be a stickler but your last drawn WL intersected the shear of the transom rather than the LWL, hope you caught it before making the table of offsets. Thanks for the lessons, I look forward to these videos.
Bob replied to another comment that he caught it in editing the video.
@@thomasarussellsr oh good, thanks.
Not to be “that guy” genuinely curious. When you measure station 6, you don’t round up to 2.73. Would that make a difference when converting up to life size?
I was thinking the same thing. However, in other measurements he only took the hundredths spot when the thousandths spot was an 8. So he stayed consistent with dropping the thousandth spot completely. Fairing the wood hull with plane and sanding board's should make up any difference. Besides, I think it is going to be fiberglassed, in which case the epoxy will float the low spots for the most point. Good eye though.
Good question! This is a 1:8 drawing. Scaled up, a maximum rounding error of 0.01 becomes about 5/64 inch. Which, yes, is measurable with the human eye - but there are limits to the precision of even very fine carpentry, and so the construction will involve a lot of sanding down to fair curves anyway, as the other @thomas notes.
Also, the next step is lofting: scaling the lines up to a full-scale drawing. This involves reconciling the coordinates from the different views, and re-fairing the curves with a batten at full scale. I wouldn't be surprised if a lot of points move at least 1/16 inch during that process.
At the end, your line on the left should not go right to the end, it should be the next one in! Great video!
Am just a little confused Bob. From your half model you seem to have made a table of off sets for the scale model. As you know the
scale of the model, can't you just multiply your measurements by the scale factor to get a full-size table of offsets?
❤️
19:00 How is the correct name of the "system" for the manufacture of frames (body) from plywood ???? No where to find study material
I just don’t know how to correctly calculate and make such frames for my needs (models)
Those measurements are call offsets. So the table of those dimensions is call a Table of Offsets.
👍👍🙂
I want to sculpt a model for those ducks that look like whales, for casting.
You need to build a half tub of water to float them.
Almost as difficult as building a chair if your knees bent the other way.
almost too painfully slow to watch
this is a video about producing line drawings from half hull models. what were your expectations? Perhaps you are in the wrong place.
Maybe you would be better suited to a CAD drawing channel?
Great video Bob. Very good example of developing the lines from the half model. Thank you for the two inset videos on the making of the ducks (beautiful work and my favorite color) and the demonstration with Mr. Gartside. My first experience with drawing lines for boats was sparked by reading Francis Kinney's 'Skien's Elements of Yacht Design.' I still have most of my curves from that adventure. Will have to get them out and try my hand at it again. Thank you so much for bringing us along on this new adventure.
Thanx for sharing this very educational Information. Very useful!
great video! I was using the same process when building a 500 fot long destroyer ship for yhe US Navy
I see by the spelling typos that you have meaty thumbs, just like this Army guy. Thanks for your service, Sailor/ship-maker.