New watches with vintage design: Fortis B-47 Calculator

There it was! A bulky multi-purpose two crown calculator watch by Fortis. They call it he B-47 Calculator, and this is what it looks like.

The first question that comes to mind when coming across a watch like this would be, "Is this for real?" The next question would be, "What is it designed for?" The many bezel rings on this watch are actually a compilation off different features often found in vintage watches. On the outside, there is a ring that indicates minutes/seconds along with a 24-hour scale. This is the same as the inside scale next to the chapter ring on the dial. The purpose for the outer bezel is to permit a second time zone for the red hand that is actually a 24-hour hand in purpose: The red hand hand rotates in 24-hour mode instead of the normal 12 hours.

Below is a chronograph by Ollech & Wajs. It has a readable calculator scale, also known as a slide rule. Slide rules are used to make simple mathematical calculations. There is an entire website devoted to this specific piece of technical equipment, featuring watches among other things: The Slide Rule Universe

The two middle scales of the Fortis provide a slide-rule function. This function was integrated with several watch from the 1950's onwards until the 1970's, when real calculators began to appear on digital watches. Some brands like Breitling still produce these watches, such as the Montbrillant models.

This B-47 is not the first slide rule watch by Fortis. In the 1960's, Fortis produced a watch named the "Easy-Math":

In addition to the slide rule, this Fortis features a compass—a rare feature in any watch. By using the hands and the sun, North can be determined. This is an interesting feature in a complex two-crown watch with calculator, something I am sure was the starting point for creating the new B-47 in vintage style!