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 Halda Twinmaster |
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 Curta calculator (Type II) |
Prior to the invention of electronic equipment for rallying, rally teams relied on mechanical devices to help them determine whether they were on time. In most rallies, the average speed is given, and the navigator calculates the whether the team is early or late at each point on the course by knowing the mileage. The more accurate the mileage, the more accurate the calculation.
When I began rallying in 1970, the top Equipped teams preferred the Halda Twinmaster (or its single counter sibling, the Tripmaster) for measuring distance and the Curta Calculator for calculating time. Heuer watches were the preferred timepieces for accuracy.
An accurate clock has always been a necessity for staying on time. Before electronic clocks, accurate timepieces such as those made by Heuer were preferred, and there were several models made specifically for rallying.
For those who could not afford a Curta, books of tables or circular slide rules were often used to assist the navigator in making the calculations. There were also mechanical computers, such as the Kearfott Rally Computer, that would make the calculations based on the speed and distance traveled.
