Hello all just thought I'd show some pictures of my new acquisition. The Pattern 3169 is designated as a 1/5th second stopwatch, believed to be for use in naval gunnery, and Helvetia supplied an adapted version of their 'Stop' stop second chronograph to the Royal Navy for this purpose. This one is the same as the one in Konrad Knirims book and the RN serial number is only 11 earlier. As you can see the navy specified that the normal time telling hands be removed to just leave the seconds hand. The 8 o'clock pusher stops the seconds hand when pressed and when released it starts again. The 2 o'clock pusher resets to 12. When you push the pusher the lever at the top pushes against a spring and the two small wheels move upwards disengaging the centre seconds hand. When released the spring pushes the lever back down and the wheels re-engage and the hand starts again. The serial number on the back has been removed but in the right light I can see enough of it to date it to 1941. Here is a pic of a standard 'Stop' and some ads. They are small at 30mm but in about 1942 Helvetia came up with a larger, 35mm, version that also had a tachymeter scale. If anyone is interested in the Helvetia 'Stop' generally or its cousin the 'Sport' have a look at my page here: https://www.helvetiahistory.co.uk/th...ronostop-watch Thanks. Carl
Yes, it runs continuously and is stopped by pressing on the 8 o'clock pusher and starts when you release it rather than needing a second push to start again. It is reset by the 2 o'clock pusher. Thanks. Carl.