The Deltar (Delta Getij Analogon Rekenmachine, English: Delta Tide Analogue Calculator) was an analogue computer used in the design and execution of the Delta Works from 1960 to 1984. Originated by Johan van Veen, who also built the initial prototypes between 1944 and 1946, its development was continued by J.C. Schönfeld and C.M. Verhagen after van Veen's death in 1959.
The Deltar was first put to use in 1960, and was the successor to a previous analogue computer, the larger Electrisch model van waterlopen (English: Electric model of watercourses).[1]
The Deltar was specifically designed and built to perform complex calculations necessary to predict tidal movements and the effects of interventions such as the construction of compartmentalisation dams in the Delta area of the Netherlands. The Deltar's design was based on the hydraulic analogy between the phenomena of water and electricity. Analogous to water level, flow, inertia, and water storage, the design of the computer used electrical phenomena such as voltage, current, self-inductance, and capacitance.