One of the great things of simulation studies is the possibility to perform trial and error exercises over and over again, until you are perfectly ready to perform the operation at sea. 

For example testing of procedures and possible tug configurations in order to identify the most optimal and safe operations.  

Offshore Design Engineering Ltd. (ODE) was assigned by Vattenfal to ensure the tow-out of the A2Sea owned jack-up barge Sea Jack from the port of Belfast. Performing tow-out from the port of Belfast is a bit tricky as the barge has to pass near the oil berths placed in the bend of the Musgrave Channel. Therefore, it was pivotal for ODE to be absolutely certain that it was safe to tow out the barge from Belfast and also find the most suitable tow-out strategy in relation to safety. 

SimFlex Shipyard 

FORCE Technology was chosen to perform simulation studies of the tow-out using our in-house advanced full-mission tug simulation system. A database modelling the Belfast Harbour and navigable surroundings was developed on the basis of available sea charts and input from the client. Also, three ships were developed for the project using the SimFlex Shipyard software a jack-up barge named ’Sea Jack’, a conventional tug called ’Beaver’ with 70 t bollard pull and a conventional tug called ’Sea Golf’ with 40 t bollard pull; all part of A2Sea’s fleet. Additionally, two ASD tugs were chosen from FORCE Technology’s database of more than 500 ships. 

All parties participate 

Besides FORCE Technology’s experienced captains and naval architects, ODE, Vattenfall, A2Sea, Belfast Harbour tug masters, Belfast Harbour Authorities and Svitzer participated in the simulations. The procedure of gathering all the involved parties ensures that decisions are based on an a common experience and understanding, and it is therefore easy to agree on the best tow-out strategy.

Normally it takes some time for everyone to obtain a common ’language’ and get into a routine on a large project. But after three days in the four coupled simulators where the participants sailed in/out of Belfast Harbour several times, the communication was running smoothly as if they had worked together for months. Therefore, the testing of the different tow-out strategies and tug combinations also went smoothly, and the outcome of the simulations was that a combination of two conventional tugs connected aft and fore of Sea Jack and at least one ASD tug connected to the side was sufficient for a safe operation.