1. ADAM4EVE workshop on Adaptive Ship Hull Forms
Adaptive Stern Geometry
Thomas Stoye, Knut Frömming
Flensburger Schiffbau-Gesellschaft
June 4th, 2015
VTT Technical Research Centre of Finland, Espoo

2. Table of Contents Motivation & Objectives Evaluation Methods
Evaluation Results
Demonstrator
Statement from class societies
Conclusion
Source: CALMAC

3. Motivation Design to specific design-point
Operational profile consist of many points
Adjustment of hull-form to actual operation point
Stern part promising
Adaptation physically feasible
Source: FSG

4. Objectives Stern wedge change possible Large impact on resistance
Identification of movable part
Variation of length and angle within boundaries
Change hydrodynamic body
Movable duck-tail
Source: FSG

5. Evaluation Methods CFD-study to determine parameters of variable part
Viscous flow methods for resistance evaluation
Selection of promising parameters
Design of steel structure and piping-system
Structural evaluation by class-rules and FE-Calculations
Further evaluation of performance by model tests
Resistance, open-water propeller and self-propulsion tests

6. Evaluation Results - CFD
Variation of length and angle within boundaries
Movable duck-tail with fixed angle selected
Resistance reduction of up to 3% for some operational points
Longer flap for larger speed
Shorter flap for slower speed
Flap Length [cm]
Flap Angle [°] 80 7 14 20 30 40

7. Evaluation Results – Model Tests
Source: ADAM4EVE-WP10 - VTT
Verification of CFD-Results for resistance by model tests
Additionally open-water propeller and self-propulsion tests
Savings for large draft and high speed up to 7% of PD
Fuel Savings for machinery arrangement and given operational profile ~3-3.5% per year
Larger Benefit when implemented in new design
Source: ADAM4EVE-WP06 - FSG

8. Model tests
A new modular ship model, scale 1:16.697, was built for model tests
Model propellers from FSG were used.
The model scale resistance and propulsion tests were performed for the RoPax ship model with an adaptable stern geometry. 8

9. Draft in the resistance tests [m] Draft in the propulsion tests [m]
Model test program
Test program for the resistance and propulsion tests
Speed points:
The model test speeds: 13, 14, 15, 16, 17, 18.5, 19.5 and 20.5 knots in full scale, (1.637 – m/s in model scale).
In the CFD computations the selected speed points were 14 and 19.5 knots.
Measured quantities:
Open water tests of the propellers.
Resistance test: towing force, sinkage fore and aft.
Propulsion test: towing force, number of revolutions, thrust and torque of the propellers, sinkage fore and aft.
The analysis to the full scale was made using ITTC-78 method.
Hull version
Flap length
[m]
Flap angle
[°]
Draft in the resistance tests [m]
Draft in the propulsion tests [m]
Initial aft (no flap)
0.0
4.8, 4.2
Short flap
0.4 20
4.8
Long flap
0.8 14 17 9

10. Resistance tests results T=4.8m
Opimum flalp angle depending on speed
max. Flap angle is never the best => optimum within measured range 10

11. Propulsion test results T=4.8m
Propulsion optima are not always euqal to resistance optima:
=> Pressure field of propeller influences trim/draught of ship 11

12. Resistance tests results T=4.2m
A significant influence of the draught on the working principle of the flap can be seen
=> Adaptable system useful 12

13. Propulsion test results T=4.2m13

14. Evaluation Results – Structure
Steel structure designed in 3D
Class-Rules as basis for design
Slamming loads determined by CFD
FE-model used for direct calculations
Critical areas identified – No show-stoppers
Steel structure to be improved in next stage

15. Demonstrator Visualization of principle Steel structure with actuator
Simplified 1:5 model
Production ongoing
Source:
ADAM4EVE-WP06

16. Demonstrator Installation of pneumatic actuators Functional test
Identification of robust pneumatic system

17. Class Societies Evaluation
No major HAZIDS identified
All risks are of controllable extend
Details of fixation, dimensioning of piping-system to be looked
Control-system and maintenance to be designed more detailed
Evaluation for each individual application to be examined
Source:
ADAM4EVE-WP06 FSG

18. Conclusion Performance of idea very promising
Implementation feasible and realistic
Results certain due to model-tests
Structural challenges can be solved
No major HAZIDS identified
To be developed and evaluated for each individual ship

19. Thank you for your attention!
Source: VTT
Thank you for your attention!
The Project is funded in the Seventh Framework Program of the European Union - Contract No.: SCP2-GA

20. The Project is funded in the Seventh Framework Programme of the European Union
Contract No.: SCP2-GA