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2. Background. The project was initialized by Sintef Fisheries and aquaculture AS together with Rolls-Royce Marine AS.A reference group of eight ship owners with one or more stern trawlers in operation were established. The main objectives of the project were to develop new and improved techno
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1. 1 The Next Generation Stern Trawler Birger Enerhaug, Roar Pedersen
SINTEF Fisheries and aquaculture
Norway
1th International Symposium on Fishing Vessel Energy Efficiency, Vigo, Spain, May 2010
2. 2 Background The project was initialized by Sintef Fisheries and aquaculture AS together with Rolls-Royce Marine AS.
A reference group of eight ship owners with one or more stern trawlers in operation were established.
The main objectives of the project were to develop new and improved technology in the trawler fleet in order to reduce the fuel consumption, and improve the safety and working conditions on the trawl deck.
3. 3 Fleet data From 1974 to 2000:
Engine output increased by 275%
Tonnage increased by 209%
The vessel length, however, increased by only 18%.
The majority of the last generation of stern trawlers were built between 1986 and 1990
The installed main engine power in these vessels is between 3-4000 kW
Gear: Single trawl ? Twin trawl ? Triple trawl
4. 4 Goal To improve:
Hull form and propulsion parameters with respect to energy consumption,
as well as the possibilities for improving manoeuvrability and energy saving by transverse and longitudinal transfer of the trawl/towing blocks.
5. 5 Profile of models
6. 6 The Next Generation Stern Trawler
7. 7 Rudder arr. on the twin skeg hull
8. 8 Main particulars of models
9. 9 Propeller and nozzle data
10. 10 MARINTEK Towing tank
11. 11 Test programme Calm water
Resistance: 10 - 18 knots (full scale)
Propulsion: 10 - 18 knots
Towing pull: 0, 4 & 7 knots
Trawling: 4 knots
Trawling w. driftangle: 4 knots (0, 7 & 15 degr.)
Regular waves
Propulsion: 4 & 8 knots
Irregular waves
Propulsion: 4 & 8 knots
Trawling: 4 & 8 knots
12. 12 Propulsion tests in waves
13. 13 Trawling arrangement
14. 14 Trawling arrangement
15. 15 Trawling with drift angle
16. 16 Towing point arrangement
17. 17 Results – Calm water
Resistance ( Effective power, Pe =Rts·Vs )
Brake power (Pb = Pd/?M)
(Pd = Pe/?D = Delivered power)
Towing pull
18. 18 Effective and brake power
19. 19 Wave profiles – Calm water, 10 knots
20. 20 Wave profiles – Calm water, 16 knots
21. 21 Propulsive coefficients, ?0 and ?D
22. 22 Towing pull – 4 knots
23. 23 Towing pull – 4 knots
24. 24 Thrust calculations – 5 knots, D=3.8m
25. 25 Results – Power in waves
Regular waves
Irregular waves
26. 26 Delivered power (PD) in regular waves
27. 27 Power in irregular waves and calm water
28. 28 Trawling in calm water and irregular waves – 4 knots
29. 29 Yawing moments for twin skeg hull
30. 30 Delivered power (PD ) at 15 degrees drift angle - twin skeg hull
31. 31 Conclusions There is a potential to improve the propulsive coefficients and the resistance of the twin skeg hull.
The bulbous bow did not work properly in the low speed range and should be redesigned to be more optimal in the low speed range and at the normal steaming speed of 12 knots.
The open water efficiency is increasing when trawling or advancing in bad weather. Based on the experience with twin screwed anchor handling vessels there should be a potential to improve the quasi-propulsive coefficient ?D from 0.41 to approximate 0.5.
It is possible to reduce the power demand by 20 to 25 %.
32. 32 NGT – Gear handling
33. 33 Thank you for your attention!