Small Craft Data Sheets

[Hannu Rantala]

Hello!

Does anyone know where to get SNAME "Small Craft Data Sheets" and "How to Use the SNAME Small Craft Data Sheets for Design and for Resistance Prediction" for free? It would cost 100$ to buy it as a nonmember.

Hannu Rantala

[CGN]

for free????,....university library or maybe in your local library.

[Davor]

Mr. Rantala,

If you need any resistance calculation and recomendation of propeller just pass the data to me for calculation.

If you are interested in calculation of resistance and propellers visit my web site www.sea-power.net

best rgds

Davor Ogresta

[Hannu Rantala]

Mr. Ogresta

I am doing my final year project of predicting resistance of planing hulls. It is a review on common methods and concentrates closely on Savitskys method. I have been doing excel based program which calculates resistance values for given speeds. I will give you data of certain hull and maybe you calculate values with your program. Your program is interesting me. It is not impossible to buy it.

Maybe we can discuss resistancen prediction more on this page? It is very interesting. I have also got acquainted with speed estimations of sailing yachts using DSYHS method. Is it familiar to you?

Originally Posted by Davor

Mr. Rantala,

If you need any resistance calculation and recomendation of propeller just pass the data to me for calculation.

If you are interested in calculation of resistance and propellers visit my web site www.sea-power.net

best rgds

Davor Ogresta

[Davor]

First of all I must tell you that last year I met an engineer Hannu Rantala, working for Kone cranes in Finland,and I tought that it is him.
But now it is clear that there is another Hannu Rantala, and it will not change our discussion on resistance.

As you saw I have programmed 14 methods for different hull forms, and you can pass me a data of the hull you want to test and I will pass you my results.

Regading Savitsky method I found one Excel spreadsheet on the forum, There were 3 methods for semidisplacement hulls (Savitsky, Wolfson and YP series).
You can look for and download it (Design > Software...)

For sailing yachts I have Delft series and it works well.

rgds

Davor

[Hannu Rantala]

Thank you for the tip! I hadn't got these spreadsheets yet and the may be of good value for me.

I have thought about one detail regarding Savitsky eguations. When calculating increase in wetted length to beam ratio, there is one given graph for increase in function of trim angle. But somewhere is told that increase shouldn't be taken in calculations when trim angle is less than 4 deg. But if you program equations like this, there is sudden uncontinuity in graphs.

How has you cleared this?

[Davor]

Go to :

Boat Design Forums > Design > Software

and than look for:

Savitsky Power Prediction ( 1 2 )

Regarting 4 degrees angle you are commenting I do not have these information, but regarding the sharp change of the power curve it is o.k.

Something like that you can find at Radojcic method at speeds around Fn_del=4.


rgds

Davor