# Delft series

Discussion in 'Boat Design' started by willfox, Aug 28, 2009.

1. Joined: Oct 2008
Posts: 79
Likes: 1, Points: 8, Legacy Rep: 22
Location: southampton

### willfoxJunior Member

I am currently workng on a delft series excel program. I am using the regression coefficients which were based on pre 1992 yachts as i am designing a heavier displacement classic cruiser. Im not too sure if I have got the correct equation.

has anyone got a link to this equation. I seem to be getting silly figures such as 1500kN at a Fn of 0.35 for a 13 m lwl and 20 odd tonne yacht?!!

2. Joined: Jun 2003
Posts: 512
Likes: 40, Points: 28, Legacy Rep: 506
Location: Kotka, Finland

### terhohalmeBEng Boat Technology

The residual resistance number is more or less on the spot but not kN, just N. Don't forget viscouse resistance.

Terho

3. Joined: Oct 2008
Posts: 7,666
Likes: 1,550, Points: 113, Legacy Rep: 2488
Location: Japan

can you post the output?

4. Joined: Jul 2003
Posts: 3,056
Likes: 343, Points: 93, Legacy Rep: 1306
Location: Thailand

### AlikSenior Member

I always use 2-4 methods for resistance prediction (of course, proper methods with matching parameters). Never trust only one method to predict the resistance...

For heavy displacement boat - try trawlers/tugs series. Delft series is known to underevaluate resistance of heavy motorsailers, while formally parameters of series match.

5. Joined: Jul 2003
Posts: 3,056
Likes: 343, Points: 93, Legacy Rep: 1306
Location: Thailand

### AlikSenior Member

This is sample for 16m trawler-style boat powerboat, calculated by same software.

Need to say that formally boat fits in parameters of Delft series, but resistance is very different due to variations of hull shape.

#### Attached Files:

• ###### Resistance_O1600.jpg
File size:
324.8 KB
Views:
897

6. Joined: Oct 2008
Posts: 79
Likes: 1, Points: 8, Legacy Rep: 22
Location: southampton

### willfoxJunior Member

Im not too sure how i would attach the spreadsheet unless i could get email numbers?

Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.