What is the "Glasen" (striking the bell)?
The task of a modern bell clock on a sailing ship used to be performed with a ship bell and sand clock on the old days. Sailing ships were guarded by at least one crew member all around the clock who was in charge of monitoring the ship. The first watch duty began at 4 o'clock in the morning and lasted for four hours, divided into 8 bell strikes.
To clearly signal the time to every crew member the ship bell is rung every 30 minutes in a rigid rhythm, beginning at 4.30 in the morning. At 4.30 the bell chimes once, at 5 o'clock it chimes twice, at 5:30 it chimes three times, and so on. After four hours and eight chimes, the watch duty is passed onto another crew member, and the cycle starts again.