The ship’s bell strikes in 30 minute increments over a 4 hour “watch” period. There is one bell strike for each 30 minute segment beginning with a single bell strike at half past midnight and counting up to 8 bell strikes at 4:00 a.m. marking the end of the 4 hour watch period.
At this point the bell strike pattern begins again at a single strike at 4:30 and counts up to 8 strikes to 8:00. The cycle is continuous over the 24 hour shift watch period.
For more information, check out the blog Page and the ship’s bell article. .