We report on a dynamic simulation of defective color vision. Using an RGB video camera connected to a PC or laptop, the captured and displayed RGB colors are translated by our software into modified RGB values that simulate the color appearance of a person with a color deficiency. Usually, the simulation of deficient color vision is restricted to static images and to dichromats (lacking one cone type). We are now able to also simulate color blindness in near real time video, and for both dichromats and anomalous trichromats. We discuss how these techniques were applied in a field study into color vision requirements in Dutch maritime practice and present visualization examples thereof.