There is hard competitive environment in production industry and shipyards have a lot of competitors. Under these circumstances, the process improvement operations are very significant in shipbuilding industry. In recent years, shipyards have been attempting to improve their processes by investigating their current production system so that they can keep their competitive power in global extent. Shipyards seek to decrease the cycle time of the interim products in order to increase the annual production capacity and the market share of the shipyard. In order to do this, shipyards have to analyze their own production system and perform some improvements on the current production system. In this study, the process improvement model is presented. The process improvement model consists of the continuous improvement method, OPT (Optimized Production Technology), and simulation. The phases in the model were implemented for a double bottom block of a container ship. As a result, by doing some improvements on the current production system, the cycle time of the double bottom block was shortened. The rate of the improvement of the cycle time is about 100% in theory. The results of the study are discussed in the final section.