Welding processes play a major role in ship production. If the welding process can be performed in less time, ship fabrication can be completed in a shorter time. Therefore, it is a significant issue for welding time to be ended as soon as possible. For this, the operator factor, which is a component of welding time calculation, could be increased. If this is done, welding time could be decreased. The purpose of this study is to determine the effects of operator factor on the production quantity of a panel line. Here, the panel line of a shipyard situated in Turkey was illustrated as an example. Whole workstations of a panel line were taken into consideration and modeled in a SIMIO simulation environment. By changing the operator factor in a web welding work station on a panel line, different welding time values were achieved. These welding time values were then inserted into a simulation model and the model was run for a specified period. Finally, the production quantities of the panel line were obtained as an output. Thus, the effects of a changing operator factor on panel line throughput were determined. (C) 2013 Sharif University of Technology. All rights reserved.