IWC Aquatimer Split Minute Chronograph

Countdown chronographs. Chronograph watches were design to measure short intervals of time like the period of time it takes a runner or race card to finish as lap. With the addition of sub-dials, chronographs now are useful for measuring and displaying periods of time of up to 12 hours.

Recently, there has been a trend to use chronograph watch designs more clearly display a period of time relevant to some sports activity. The Rolex Yatchmaster II and Omega Seamaster NZL-32 were designed to display more clearly the 10 minute countdown to the start of a regatta. The Omega Seamaster Apnea to countdown a period of 14 minutes.

The IWC Aquatimer Split Minute Chronograph tries to bring more functionality to the divers watch.

IWC Aquatimer Split Minute Chronograph. The IWC Aquatimer Split Minute Chronograph follows the same general design as their Aquatimer Automatic 2000 divers watch. It is a divers watch, which instead of having a rotating outer bezel, it has a rotating ring behind the the sapphire glass cover. The bezel can be rotated by twisting the crown at the 4 o'clock position. This crown does not screw in, and thus can be used even under water.

However, the Aquatimer Split Minute Chronograph, is as its name says a chronograph, and has three sub-dials: one to displays continous seconds at 9 o' clock; and two to display elapse times of 30 minutes and 12 hours, at the 12 and 6 o' clock respectively. Like a conventional chronograph the main seconds hand is used for the chronograph function, and the buttons at 2 and 4 o' clock are uses as Start/Stop and Reset buttons. The reset button of the chronograph is the same button used to rotate the inner 60 minute timer ring.

What makes the Aquatimer Split Minute Chronograph unique is the little rocker switch on the left hand side of the watch. The watch has two main minute hands (one yellow and the other black and yellow), superimposed over each other. When the rocker switch is activated, one minute hand stops moving, and this can be used for measuring the period between the stop hand and moving hand. IWC designed this so that the the rotating ring could be used to measure overall dive time, while the split minute function to measure another relevant even like the period of ascent or the length of a decompression stop.

Specifications. The Aquatimer Split Minute Chronograph is a large watch with a 44mm case diameter. Despite its size it is a light watch thanks to its titanium casing. The case can be mated to your choice of either a titanium bracelet or rubber strap.

Movement. The Aquatimer Split Minute Chronograph uses the IWC Calibre 79740 mechanical self-winding movement. This movement produces 28,800 vibrations per hour and has a 42 hour power reserve. The movement has a date display is at the 6 o'clock position.

Divers watch? The chronograph and split seconds function can be used at the divers rated depth of 12 bar (12 ATM or 120 meters). Now, 120 meters may sound like a lot, until you look at what 120 meters water resistance means from ISO regulations. Normally, a watch used for scuba diving should have a water resistance rating of at least 200 meters, and most high end swiss watchmakers give their divers watches water resistance ratings of at least 300 meters.

About IWC. IWC or the the "International Watch Co. Schaffhausen" was founded by an American engineer from Boston, Florentine Ariosto Jones, in Schaffhausen, Switzerland in the year 1868. IWC Schaffhausen is notable for being the only major Swiss watch factory located in eastern Switzerland, as the majority of the well-known Swiss watch manufacturers are located in western Switzerland.