Boat Hulls Pro's and Cons

[Boorman]

Hello all!

I am new here and am currently working on a "custom" boat design, however I am also writing an essay in realtion to the whole project and am in DESPERATE need of help from people with more know how than me!

I am hoping that someone would be so kind as to help me with the pros and cons of each of these hull designs.

I asked on Yahoo answer but the reply was of no help.

These are the hulls I need help with.

Smooth Curved Hulls pros and cons please?

Chined & Hard Chined Hulls pros and cons please?

Flat Bottomed Hulls pros and cons please?

Many thanks and no doubt I will again be in need of your thoughts and opinions.

Boorman

[river runner]

It depends on what kind of boat it is and what you want to use it for, but here are a few generalities. I'm no expert, by any measure, but there is one thing I think I can say with certaintly. The more chines, the more choices you have in shaping the hull, but the more work it is building it. "Smooth curved hulls" basically have an infinite number of chines. The simplest boat to build is a single chine, flat bottom, stitch&glue. There is a lot to be said for simple.
A flat bottom has three potential advantages. I say potential because it depends on other factors. But generally speaking a flat bottom boat has less draft, good primary stability (doesn't feel tippy), and works better when beaching the boat. But it also has significant disadvantages.
I think a lot can be said for a V-bottom boat if you don't intend to beach it and draft isn't as high a priority.
Most high end canoes have a shallow arch bottom. This has been found to be the best all around shape for this type of boat and probably works well for most displacement hulls.

[PAR]

Boorman, this isn't meant as a personal insult, but frankly if you have to ask as basic a set of questions as these, you are no where remotely close to having the skills and understanding necessary to - - -

Originally Posted by Boorman

. . . am currently working on a "custom" boat design . . .

The best advise you could receive at this point is to continue your studies in yacht design fundamentals, which will provide the answers you need. Of course this will take some time, likely not soon enough for your essay, but a quick and simple answer to your questions isn't possible, without considerably more understanding on your part.

For example Froude numbers often dictate hull form choices as does the design's SOR specifics. With an application specific SOR in hand, you have natural choices available and the differences between hard chine or round bilge or other hull form configurations, become moot considerations.

[Boorman]

Hi you guys, much appreciated on the advice and trust me I take no insults to being told whats what, in the end I am a novice, so it's best i be informed.

I have tried to view online plans and have viewed several images of various different hulls and what not, but none of them are very fourthcoming on their advantages and disadvantages.

My essay states only that I need to show 4 pros and 4 cons for each, I admit thats a hard task for someone such as myself, because I usually only ever draw images of boats and custom design boats. (Not sure if they'd ever work) but I like different.

I appreciate the input so far, thank you.

[eyschulman]

As a none professional in this feild I veiw boat design in two major components. The art and the engineering. I judge a boat good when both are right. If you can draw artful boats and have no clue about the engineering part either get educated or find a partner to do that aspect of the design. I suspect it works that way in large design firms where there are multiple inputs into a project.

[tom28571]

There is a book on this subject written for the layman that introduces the factors you wish to address. It in no way will qualify anyone to design a boat but will make some of the differences and their effects on the overall performance of the boats more clear. It is an easy read and might just be what you need to get started on your project.

"The Nature of Boats" by Dave Gerr. Available on amazon or ABE books fairly inexpensively. After going through that one you should be able to tackle "Skenes Elements of Boat Design" or similar. If you are still game after that, there are a number of more technically advanced or specialized books available.

This forum is good for specific questions and discussion but is a poor resource for basic information that must be mulled over and devoured if you are to understand the importance of it.

[DCockey]

Gerr understandably does some considerable simplification of the physics in his explainations in The Nature of Boats along with various assumptions. These work okay for the boater who just wants a better understanding of how boats work. My criticism is that he doesn't come close to making it clear that reality is considerably more complicated so someone may read the book and assume they then know more than they do.

[tom28571]

Originally Posted by DCockey

Gerr understandably does some considerable simplification of the physics in his explainations in The Nature of Boats along with various assumptions. These work okay for the boater who just wants a better understanding of how boats work. My criticism is that he doesn't come close to making it clear that reality is considerably more complicated so someone may read the book and assume they then know more than they do.

Undoubtedly true David. The main thing is that they will know more than they did before reading the book and, I think enough to go into more meaty material. I also have a couple of quibbles with some of his statements or computations but is there a better introduction to the material for a beginner? I don't know of one. On the whole, I think it is an excellent introduction.

[PAR]

Agreed Tom, particularly when the words "esoterica" and "obsessed" are included in the book's title.

[cyclops2]

Are you, Boorman, related to the Boorman boat builders of the 1920s ?

[Boorman]

Hi again you guys, much appreciated the continued thoughts.

I shall have to look for that book "The nature of boats" to see what I can learn from it, again i am grateful for all the feedback, its just what I need to be honest.

This project is only to express a demonstration of creatability and will by no means be full scale. It will hold no passangers and have no working parts.

A much as that is a disappointment to me, i will want to do my best to pass this essay.


Its interesting and again agreed by myself about people's thoughts on getting a partner and help on the project etc, the problem with that is outside of the class, I cannot find anyone who has any interest in boats or amphibious craft at all.

I am not sure if any of my classmates have a partner to help them, but sadly I do not.

Its rather weird I feel, I have always liked boats and watervraft in general yet, not many others do!

I have always found this to be a major dissappointment really.

[Boorman]

Originally Posted by cyclops2

Are you, Boorman, related to the Boorman boat builders of the 1920s ?

No relation my friend,