Full scale ACS test 1 full year before STENA E-MAX model / Toyship...

1. Telefax
Kgs. Lyngby, 11-11-2008
Sea Trials with ACS Demonstrator
To: DK-Group Fax. No.: -
Attention: Christian Eyde Møller Order No.: 108-29210
Sender: TEF Number of
pages:
2
Executive Summary on Sea Trials with ‘ACS Demonstrator’
Starting in 2005, DK-Group has made an extensive research & development study at FORCE Technology on
application of ACS-technology on tanker vessels. Based on their previous studies and knowledge DK-Group
has made a comprehensive model test programme for large tankers hull forms and the resulting figures
proved a potential for reduction of the resistance by means of ACS technology. However, in order to analyse
the scaling effect of the air and water interface one of the main recommendations from the model testing
studies were to test and verify the technology on a larger vessel.
Based on this advice, DK-Group in 2007 purchased the ‘ACS Demonstrator’, which is a suitable 83m Multi
Purpose Vessel for demonstration of the ACS Technology. A comprehensive sea trial test programme of the
original reference vessel was conducted in the Oslo Fjord in June 2007 in perfect weather conditions.
Hereafter, the vessel were retrofitted with ACS during the early 2008, and subsequently tested in full scale in
September 2008.
Prior to the retrofitting of ACS, a large model testing programme was carried out for optimisation of the
design of the air cavities in the flat of bottom. The tests were made with an approximately 8m scale model
of the ‘ACS Demonstrator’.
After the completion of the conversion, sea trials were made with the ACS system activated. The tests were
made on the same test track in the Oslo Fjord, also in perfect weather conditions. The sea trials of the ACS
Demonstrator was a success, and the results of the trials showed a clear constant reduction of the
propulsive within the range as expected from model tests. Furthermore, video recordings showed a smooth
and stable flow within the air cavities.
FORCE Technology, Kgs. Lyngby
Hjortekærsvej 99
2800 Kgs. Lyngby, Denmark
Tel. +45 72 15 77 00
Fax +45 72 15 77 01
FORCE Technology Norway AS
Claude Monets allé 5
1338 Sandvika, Norway
Tel. +47 64 00 35 00
Fax +47 64 00 35 01
info@forcetechnology.no
FORCE Technology Sweden AB
Tallmätargatan 7
721 34 Västerås, Sweden
Tel. +46 (0)21 490 3000
Fax +46 (0)21 490 3001
info@force.se
FORCE Technology, Headquarters
Park Allé 345
2605 Brøndby, Denmark
Tel. +45 43 26 70 00
Fax +45 43 26 70 11
force@force.dk
www.forcetechnology.com

2. The tests also demonstrated that the automatic control system for the air supply worked perfectly in both
calm water and in waves. Based on continuous measurements of the water level in all cavities, the system
continuously adjusted the air flow to the cavities.
It is concluded that the tests with the ACS Demonstrator has been a success, and based on the
measurements the scaling method of ACS technology from model tests to full scale will be developed
further.
Sincerely yours
FORCE Technology
Thomas Eefsen
Senior Project Manager
Hydro and Aerodynamics