Winyacht Advanced VPP Who makes it?

[ErikG]

As I'm trying to roundup all info I can get my hands on about diferent makers and programmers of VPP's (just got started though :-).

i'm curious about the above mentioned VPP. Blakewell-White in NZ say that they are using it on their website . But I can't find any info about it anywhere else. Any pointers?

If anyone has webpages or links to other VPP's that are not mentioned on the boatdesign.net website please let me know.

ErikG

[yipster]

Eric,

Not being an expert in this I do assume that most velocity prediction programs come with the better design software and are listed as such. Another way to go is by calculating the many variables for a specific design using formulas the D.I.Y. way, witch I think is wise to do anyway by rule of thumb.

Yipster

http://www.bakewell-white.com/facilities.htm is using winyacht as I now see you mentiont, clever aint i? cant find more eighter, maybe give them a call or mail? also see http://ds-t.com for phaser (a rhino3d plugin) and fastyacht for their VPP that includes one or more heel angles (needs a VCG). as does hullform free even on cats! together it’s offered for $1500 but I’m still thinking… a VPP search on this forum also gives 15 results (now 16), "velocity prediction programs" on alta vista over a hundred. want to keep us informed what design your brewing up?

[yipster]

...

just found a nice free calculator, a hull resistance aplet that calculates frictional wave and total resistance (air not included) against length, beam, weight, Cp, Cp1 and speed. ah, that does save calculating as i was was at. and wow, frictional resistence (for my purpose) is so low i want to check it the D.I.Y. way. great toy, check it out! http://www.users.globalnet.co.uk/~fs...reads/fred.htm

[ErikG]

I have several designs in my "pipeline"

As I'm still learning, mostly from books but I have started with YDS although I'm progressing very slowly. Since I'm a computer buff I have a hard time leaving the computer and boatdesign programs aside and really spend as much time handdrawing as I should.
Having two small children and more than a full time job doesn't help either...
Enough excuses already! I need to find another type of job that lets me do more of what I want to do.

The design ideas are mainly three at the moment...
1• 33 foot sailboat, lightweight cruiser racer for ordinary people. that is for people like me. A design with lots of fun built in :-)

2• 25-26 foot sailboat, mini cruiser for the beginner sailor/sailing family. With some but simple comfort and dead cheap.

3• 44 foot sailboat, bluewater cruiser for around the world cruising but with an emphasis on speed and "liveability"/comfort (I know that is a contradiction).

And eventually I want to design and build my own Open 650 Mini Transat,but to be really competitive I need to learn a lot more so design 1 & 2 above will probably come first.

That's it for now. When I get far enough on my designs I'll share the ideas more thoroughly with you all.

Erik

[Laz]

Hi Erik;

I'm sort of doing the same thing as your option #1, except I'm planning to take an existing hull and redo the insides, basing my modifications on several different boats that I have chartered. I am hoping to use Rhino to help with the CAD work.

I've got the kids too, so I understand what you're going through. Our timetable is a bit slower, 5 years at least, but by then I'll be really good at the computer programs.

I'm looking forward to reading your ideas.

-Laz

[Matthew]

Forgive my ignorance but what is Cp1 in the calculator formula?

[yipster]

prismatic coeficient, try the calculater, see the differences in the wireframe this makes, read the info and see the results, try and enjoy! how to set this CP to a froude nr. as done here for a racing canoe i'm still studying.

[giramonti]

My advice to someone interested in VPP's is to write your own. Use VisualBasic, which is a very easy programming interface and can be used for many quick and dirty little programs. It's very easy to learn if you've done any programming, and may take several weeks of regular use if you are a newbie.

Basically you'll need to create a solver algorithm that finds equilibrium of lift and drag, at a given windspeed, resulting in boatspeed. Simple VPP's will estimate difference in lift and drag due to heel by empirical formulas, others will, like mine will work with three dimensional vectors. It sounds a complicated, and it is a little a bit, but the rewards are worth it. It took me about a year to write my VPP and make sure it came out with reliable numbers, vis a vis the IMS VPP.

That's sounds like a long time, but what I learned about the inner workings of a VPP, and in turn, what I learned about the hundreds of different aspects of a design that can be manipulated towards a faster boat was invaluable for my skill and knowledge level.

The guide which I think is indispensable in writing a VPP is van Oossanens "Predicting the Velocity of Sailing Yachts." The formulas you need to write a VPP are all in there. But, be warned, I've known some very sharp designers who have trouble with understanding this paper. So, there are two other books that I recommend to go alond with this paper, which by the way is about fifty pages, they are Larsson and Eliasson's Principles of Yacht Design, and Claughton's Sailing Yacht Design: Theory. Both books can be used to write a VPP. The former is easier than the latter, and both are easier than van Oossanen's paper.

Good luck.

[nico]

Hi

i am myself in the process of writing a vpp under excel ( with the help of VBA) . The paper from Van Oosaanen is really nice, everything is in there. Do you know anymore papers interesting ?

Thanks

Nico

[dionysis]

hello all,

I have searched the net for the Van Ooosaanen's paper on vpp formulae you are referring to, but have not been able to find it.

Where does one get this paper? Do I have to subscribe somewhere?

thanks in advance, dionysis

[nico]

The piece of art is called:

Predicting the speed of sailing Yachts
Sname Transactions vol 101, 1993 pp.337-397

It is probably difficult to get it. You should try to contact SNAME.

Nico

[dionysis]

thanks again nico.

dionysis

Anybody out there who wants to share a (home made) VPP.
I think a lot of people do understand what a VPP does and how it works and would like to play around with a vpp for design, discussion or improvement purposes.

Try a search on Hans Zwakenburg or Zwakenberg.
He programmed a vpp that uses Van Ossanen logaritmes.
Found it: http://www.zwakenberg.de/hulldrag
I know at least one respected designer use this stuff

How smaller the boat how more the fault though. I made some models that are used in the studies (that are going on for years and years)
Maybe you can find the Delft University Press, they have all the Ossanen papers for sale
I must have an excel spreadsheet lying around with the same stuff, but hans did a good job, better then me.

[Repelsteeltje]

Is there a program of the same type that can calculate for sial dag and lift as well?