Design of a lock gate for Nieuwe Zeesluis in IJmuiden becomes a challenge when the boundary conditions limit the choice for the conventional types of the gate. The available width of the lock does not allow a straight rolling gate to be considered as a possible alternative as it is in most similar cases. All the initial efforts of this study have been made in search of a new alternative to solve the space limit problem. After assessment of a number of feasible type of gates, finally, when the curved gate concept was introduced based on the concept of rolling gates and sliding gates, all the functional requirements of the design had to be met. This study investigates in three different structural alternatives for the curved gate in the concept development stage as well as three different operating systems and two different supporting systems. Based on certain design objectives, a final concept is chosen and is developed into a preliminary design. The design objective have been defined based a simple criteria of achieving the most benefit with the lowest investment possible. In this manner it is tried to increase the functionality of the design for gate structure. These objectives are basically: - Minimum use of movable devices - Minimum necessity of maintenance - Innovation - Simplicity The main challenge in the conceptual design is to find the optimum combination within the alternatives for the main compartments of the gate while every advantageous solution for a compartment, introduces a new problem in another. For making a better decision a framework is defined for the evaluation of the solutions and alternatives with the help of a score system which enables us to see which alternative is in line with the design objectives the most. Furthermore, the study presents a rather detailed design of certain compartments such as operational equipment, guidance devices, tracks, hydraulic bearings and sealing system. Structural and stability checks are done for the extreme load conditions, loads during the special combined movement and construction of the gate. This results in a preliminary design which is integrated and consistent in satisfying all the functional requirements of the design. The final and most important evaluation of the research study discusses the costs, safety, reliability and availability of the gate structure by means of a qualitative RAMS analysis accompanied by a cost comparison table. These two outcomes provide insight on applicability of the gate into the different situations but especially in this case study. This report will discuss the approach and steps in which the idea was developed and it answers the feasibility and applicability questions by the help of final results and evaluations. Report ends with presenting the conclusions of the work and giving a number of recommendations.