Principles of Yacht Design as design manual???

Who is using or plans to use Principles of Yacht Design by Larsson & Eliasson as their primary guidance to design a boat? What other sources of knowledge are you using? Do you have experience in engineering or design?

 

i have studied more than a thousand hulls and rigs, study everything

 

Are you referring to Skenes? The title is Elements of Yacht Design. If so, my answer would be that it is a valuable resource but by no means all that is needed to do adequate design work.

Yes I have an engineering degree and my extensive design work has been for machinery and instrumentation, not boats. I have done numerous designs and builds for small boats but never have I represented myself as someone who knows what he is doing. The more one studies, the better to realize that there is so much more to learn. That is why we would need more than one book along with some analytical skills, and a well developed capacity for objectivity. We learn from this forum if we are able to discriminate between knowledgeable postings and crackpot ones.

 

Principles of Yacht Design is a good book, but it is not a bible of yacht design. It should be integrated with info from other books, technical papers, data sheets etc. It is particularily lacking the info about powerboat design.

My technical library is about 2 meters tall and 1.8 meters wide and it covers nearly anything one should know (for practical use) about math, physics, chemistry, materials science, electrical engineering, hydraulics, aero and hydrodynamics, turbomachinery, numerical analysis, boat (sail, power) design and building, ship stability, shipbuilding, propulsors, etc. etc. Oh, I even have few volumes about helicopter and airship design - one never knows...
But just as the curiosity never sleeps, so the library keeps growing year by year.

Of course, I'm not saying that everyone should go to these extremes, just that PYD is not enough, perhaps not even for a backyard boatbuilder.

A lots of info can be found in internet too, but the more I look around the more I see that the big part of that info is just a marketing hype. The rest is a copy&paste work from one website to another, or just a hearsay-based chatting.

I am talking just about books here, since the question was about a book. There is an equally important knowledge database called "practical sailing". It is not more nor less important than the above. They are complementary to each other.

Cheers

 

No, I was refering to Principles of Yacht Design by Lars Larsson & Rolf E. Eliasson. Originally published in 1994, the third edition was published in 2007.

 

And this is much more than any library. I'm sure one could learn a lots from your practical experience, peter.

 

Out of curiosity i measured mine. It is some 20.0m long of books, journals, tech papers etc etc. That doesn't include the many thousands of papers i have electronically (and some books too)

Can never have too many ref books etc.

 

I have only 1.2m of books (including Larsson&Eliasson and Skene), journals and papers about the same.. but I'm an amateur.. Agree with Ad Hoc "Can never have too many ref books etc"

 

Principle of yacht design is a very good preliminary book, but is missing very important features for a real boat.

Such as : bulkhead/hull juntion, hull/deck junction, chainplates local strengthening etc ... (think of forestay chainplate).

See figure 12.15 page 256 to see what I mean. (2007 edition)

Second, all manufacturing constraints are missing. A boat you can design, but not build at correct price is of rather limited interest.

 

I would say the book is good introduction for hydro- aerodynamics section, and a guide for FRP boat calculations. Say, they touch design loads and their first principles that has never been featured in Elements of Boat Strength. In terms of general planning/architecture the book is loose; there is a lot of sketching and work before calculations described could be done.

I often use Principles as reference for some issues, it is quite handy.

 

Principles is not an exhaustive naval architecture tome, and it's not suited for power boat design.

I'd recommend 'Principles' as a primary reference for smaller sailboats, it does a very good job of cramming a lot of subjects quite succinctly into 300 or so pages.
But note that it's mostly oriented towards a particular type of sailboat.

If you were designing a heavy displacement 20 meter schooner for example you wouldn't find much directly relevant material in that book. You'd then be better off with books like Chappelle and Skenes.

Fundamental NA books will teach more about design influencing factors like RAO's with respect to comfort, performance and maybe related hull and even the importance (or not) of issues like foil design.......For example Principles devotes a chapter to foils without for example warning the reader just how applicable those low drag bucket foils are once you get away from smooth water.
I've seen several times now, designers who have read nothing other than Priciples for an understanding of foils propose 5 digit NACA shapes on long chord short span keels on an ocean cruiser.

Good books for sailboat desgn apart from Chappelle Skene Skene/Kinney are books by Gutelle, Marchaj (particularly seaworthiness) and there's a nice little book by Teale called 'How to design a boat' that gives a clear overview without the maths background being assumed. Then there's a plethora of books and papers all with slightly better coverage of each subject.

So for a fair comment here it really depends what you want to design. Most designers would use class rules a lot as reference material for the engineering and prelim structural design.

 

I agree with the comments that Principals of Yacht Design is a useful but not comprehensive reference, but oriented towards the recent cruiser-racer and similar designs. I do not consider is to be sufficient as the only guidance to design a boat from. I also have a large number of books on the technical aspects of boat design, naval architecture, aerodyanmics, and a number of other topics, and more on small boat designs and and other related topics.

The reason for my question which started this thread was I've gotten the impression that there are some folks who are trying to design boats using PYD as their primary guide, and don't recognize what it doesn't cover.

 

Not even now.

When you look at recent design, such as Elan 310, Elan 350,Beneteau First 30 , First 35 you see some common characteristics:

T bulbed keel . This is a way to reduce overall boat weight, but keeping stability. Hydrodynamic of bulb not handled in PYD.

Single chainplate for shrouds, located on the hull plating, with aft swept spreaders. Structural of plating, without any bulkhead not handled in PYD.

If you look YD40, with its heavy fin keel and 6 inboard chainplates for shrouds, it will be simply way too expensive to build and sell.

Competitors will be 1 ton lighter, meaning less material, less sail area, less engine power. And way easier to build : less chainplates, and structural bulheads. and way easier to fit layout, not required by structural bulkhead position.

Among the 4 boats I have listed, it is probable at least one will reach the thousand units produced and sold.

 

Why are YOu comparing designs? Should they re-publish the book with new design every year, to beat the competitors?

With this logic, Skene's book is useless as designs published there are outdated. Just note that those Elans and Firsts are just part of the market, and still slower than some other boats

 

I am not truly comparing designs.

I am just saying that "features" that are currently mandatory for a cruiser racer design are not handled by the book. (bulb keel and chainplates on hull plating , among other). The book is not wrong at all, it just not handle these points when DCockey said the book was oriented toward recent cruiser racers.

And yes, First and Elan are only part of the market, and they are not the fastest. But sailboats over 30' that sell over 1000 units are rather few. Former model First 31.7 sold 1600, and I guess one of these newer 4 will replace it.

Now, if you look at the new Xp 38, you will also see bulb keel, and single chainplate on the plating.