Hull Design

[bobber]

exactly. if you come up with a hull that is most efficient in all sea states and against all parameters, id be interested, and im sure a lot of companies will be very interested!
so definitely need to set some boundries.

im sure interested in the results. ive never really looked into sailing boats deeply, and so would be interested to see what comes from it.

 

[Pierre Badin]

This version of SHDM program really requires some kind AutoCAD (version 2000 or newer one), that is product of AutoDesk. You should have to provide it, but the problem after that is using AutoCAD because you are probablly beginner with it.
What kind of software you use at the moment?

That's the problem, I don't use any for the moment, and I'm looking for a good compromise between simpleness, price, and quality... :-s

 

[Pierre Badin]

Ok, I'll post the essay once it's done (first copy's not due until the end of the summer holidays.) But you have to keep in mind that I don't have much knowledge in this area, hence I am not planning to spend £1000 for a high-tech program used by the NASA, that i won't be able to use to save my life. So this is why I am looking for a rather simple program to help me with the experiment.

It is true that I won't probably come up with anything new to the boat designers (heh, what do you expect...) but all I am trying to do is to prove the theories and to apply them to models.

About my variables, I think I will forget about the waves already existing on the water. I will also probably do the testing with sea water. (although I am not sure it will make such a difference... Maybe the density of it...) About the problem of the wind direction and force, I won't take it into consideration. To give you an idea, I will simply investigate the displacement of such hull on SEA water (by the way, is it simply a quesion of concentration of salt per water, or do should other factors be taken into acount?)

The experiment will therefore consider only water drag. I will assume that the force comes from behind the boat, and pushes it straight forward, creating a feedback of current, which will be what I am going to investigate.

Next time I connect, I'll register because I'm not going to have this whole debate just as a guest.
Good night

Pierre

 

[grob]

To my mind the most interesting results might come from studying the effect of different sea states on the efficiency of the hull, As a physicist you may have come across experimental design and parameter design techniques (also called Taguchi methods), a field of statistics used for determining the effects of noise factors on an experiment. In this case your noise factor could be the sea state. We used to do a lot of this when I worked for Ford. Its powerful stuff.

You could set up a fairly simple experiment, get a couple of popular hull shapes, perhaps even model boats and test them in calm and rough seas then use taguchi methods to "prove" which is more efficient. The great thing about this is the experiments which are usually the expensive bit could be fairly simple. The guts of the project is in the statistics used to interpret the results. Who knows you may be able to come up with something "new to the boat designers".

There is plenty of free software for these experimental methods take a look at http://www.isixsigma.com

All the best

Gareth

 

[Stephen Ditmore]

I think if I were doing this essay I'd try to relate any experimental component to a discussion of Froude number and Reynolds number (with a sidebar on the men for whom they're named). Those two concepts are really important to knowing how to scale your result, and are worthy of a paper in themselves.

Best,
Stephen

 

[DJPierrot]

Yes, I know. But you see, the problem is the following, I am only in high school, hence I don't have access to university material. It's therefore hard for me to do a very elaborate research.
I have already designed it more or less simply, on which you can see the current coming in the water tank, applying a pressure on the hull (which is attached to the side of the tank by a newtonmeter), and passing beside it. The current would be considered as constant, so would the length and the mass of the hulls designed (the shape varies but always the same length) An instrument measuring the tension between the side of the tank and the hull will determine how much drag the hull makes.
By the way, as you can see, I've registered, so i'm now officially a member of this forum.
Tell me what you think of it. It is only a draft, I am open to suggestions.
Good evening,
Pierre

 

[Rrobert Carelli]

I am not planning to spend £1000 for a high-tech program used by the NASA, that i won't be able to use to save my life
Pierre

Hey Pierre,

I am also doing an extended essay in the same field as you, so I think I can help you with the software problem. I used Maxsurf Academic, which hyou can download at this site, http://msacademic.formsys.com. Then i entered my high school and IB candidate number. Its free and easy to use, so it should help some.

Also, you might look into asking to usue a towing tank at a university. this is how i carried out my testing.

Good luck,

robert carelli