Is it stable enough for a powerboat?

[magwas]

Originally Posted by Alik

Why are You using this Sedov's method? it is 60-70 years old; the results are based on flat plates and thus not realiable. Use Savitsky for planning mode.

Okay, here is the result using Savitsky.

[magwas]

The 3 chined version seems to have the least resistance in this speed range according to both computing method.

[Alik]

Originally Posted by magwas

The 3 chined version seems to have the least resistance in this speed range according to both computing method.

Oops, it is 3-chined!

Then no method will take it accurately. Savitsky is for prisms with V-bottom.

[magwas]

Oops, it is 3 straked, meaning two- chined, and only one chine is under waterline.
This one:
http://www.boatdesign.net/forums/att...t-neptune4.png
http://www.boatdesign.net/forums/att..._linesplan.png

Still no applicable method?

[Alik]

Strange shape for planning boat...

There should be chine flats and hull from middle to transom should be parallel.

[daiquiri]

Magwas, I hope that you will understand that what I'm going to write is not a downplaying of your efforts or of the job done so far. It is just a (hopefully) positive and constructive criticism.

I see a lots of enthusiasm in what you are doing and that's a good beginning, but it is not enough. I truly believe that it would be appropriate for you to concentrate more on studying the principles of boat design and power prediction before continuing to post graphs like these. Hull design, stability, construction techniques, power prediction, just to name few fields where you should deepen your knowledge before going further into this project. You need to read some books first - about history, theory and practice of boat design and boatbuilding. There is a thread in this forum about recommended books, you'll find indications to some excellent texts over there.

This forum should be the last resource for you, useful when (after basics have been well digested) there will be some constructive or design details to clarify. Right now you are wandering through the muds of basics, apparently without knowing what direction to undertake and which tool to use. You have even asked about planing properties of canoe-stern hulls (example: Wanted - Somebody to enter data onto a software program for a few $$$), which means that you are at a very beginning of a learning process. Don't give up, but do it in the right direction - start studying in an organized and systematic way.

The graphs and hull lines posted so far may be a nice exercise in usage of Freeship, but these efforts will not translate into a good boat (probably neither into a real boat) if you keep going this way. Which is also a much harder way, imho.

Cheers!

[Alik]

Originally Posted by daiquiri

Magwas, I hope that you will understand that
....
Cheers!

100% agree.

Take Sorensen's and Marshall's books on powerboats as first reading, before trying to play with software and graphs.

[daiquiri]

Originally Posted by vazer

hahaha what kind of bunch of idiots you are
I am living this ****, warp drive

<mod note: for obvious reasons vazer has been banned>

The only thing I can reply to this is - have a nice voyage.

[magwas]

Originally Posted by Alik

Strange shape for planning boat...

There should be chine flats and hull from middle to transom should be parallel.

Well, I don't know much about planning hulls. The 5-strake version was an attempt to draw something similar to norman 20, but developable. Also I have just ignored the chine flat. To be honest, I did not even heard the expression chine flat until you have raised it.
Here is a page about chine flat: http://www.bowdidgemarinedesigns.com...ine_flats.html
Here is an in-depth discussion about Chine and strake design

I am back to the drawing. This one will have a V bottom (maybe slightly flatter than in the neptun4 version, so it will reach to beam), a chine flat, and nearly vertical sides. Also, it will be a simple extrusion from midship to stern.
Maybe vazer won't like it, because building this will require much fiddling around chine flat

Originally Posted by daiquiri

The only thing I can reply to this is - have a nice voyage.

More important: a immediate and fast one!

Btw.

Magwas has got some proper advice in private lessons from Ad Hoc.
But then, it needs one to teach and one to listen, the former was there.........

[magwas]

I ask you again not to accuse me falsely. You might don't know what really happened.
The conversion went somehow like this:

Ad Hoc: You do it in the wrong way, you should first produce a general arrangement
Me: I don't know what a general arrangement is, could you tell me?
Ad Hoc: figure it out
Me (after hours of googling and drawing): I came out with this is it okay?
Ad hoc: No.
Me: What the problem with it?
Ad Hoc: I already said, listen to me
Me (more googling and drawing): Here is one. Please tell me what is wrong with it?
Ad Hoc: You don't listen to me

I have given up at the end.

[Alik]

magwas, do You really expect someone will teach You the basics that are well expalined in books (not in Google!), step by step?

Pls take few books and read them; this will answer 80% of Your questions. Knowledge can not be downloaded together with software

[magwas]

Originally Posted by daiquiri

Magwas, I hope that you will understand that what I'm going to write is not a downplaying of your efforts or of the job done so far. It is just a (hopefully) positive and constructive criticism.

I see a lots of enthusiasm in what you are doing and that's a good beginning, but it is not enough. I truly believe that it would be appropriate for you to concentrate more on studying the principles of boat design and power prediction before continuing to post graphs like these. Hull design, stability, construction techniques, power prediction, just to name few fields where you should deepen your knowledge before going further into this project. You need to read some books first - about history, theory and practice of boat design and boatbuilding. There is a thread in this forum about recommended books, you'll find indications to some excellent texts over there.

This forum should be the last resource for you, useful when (after basics have been well digested) there will be some constructive or design details to clarify. Right now you are wandering through the muds of basics, apparently without knowing what direction to undertake and which tool to use. You have even asked about planing properties of canoe-stern hulls (example: Wanted - Somebody to enter data onto a software program for a few $$$), which means that you are at a very beginning of a learning process. Don't give up, but do it in the right direction - start studying in an organized and systematic way.

The graphs and hull lines posted so far may be a nice exercise in usage of Freeship, but these efforts will not translate into a good boat (probably neither into a real boat) if you keep going this way. Which is also a much harder way, imho.

Cheers!

Thank you for your advice. However in the last 20 years I have learned everything this way: depending on internet resources, and when I could not find good structured documentation, struggling through the learn-while-doing-it way or reading conversations of someone else doing it. This is why I try to post references to pages I have learnt something from, so the next one reading this will find the info easier.
Due to the fact that everyone asked about only design details here, it is very hard for a beginner to wander through the first part of the learning curve: you can find plenty of info about the details in this forum, but introductory stuff is very scarce, and there just isn't a thread which goes through the design of a boat starting with a clueless designer like me, and producing a set of useable plans.
I know it is something unheard of in this forum, (I have managed to gravely piss off apex1 with my first attempt, and as you can see he still does not understand what I am trying to achieve), but I think it would be helpful for others.
Two notable good stuff for beginners are Eric Sponenberg's thread with design figures and Vulkyn's http://www.boatdesign.net/forums/ope...uff-33407.html but those both started after I first started trying to figure out what boat design really is (and I still don't know )

Originally Posted by magwas

Don´t overestimate your power magwas, you did not.

The latter being based on my recommendations!

And it was me who asked Ad Hoc to give you a helping hand when you joined the Forum!
But soon was clear that you are not willing to do some legwork yourself, and the 101 for Naval Architects cannot be spoonfed to anyone.
And that is the crux, you are trying to study something like heart surgery over the internet! A dumb attempt.

Richard

[magwas]

Originally Posted by apex1

And that is the crux, you are trying to study something like heart surgery over the internet! A dumb attempt.

Don't underestimate the power of internet. I have managed to do that with IT security (another interdisciplinary topic which needs deep knowledge of multiple disciplines) with a great success.