Dog watch of Ship's Bell clocks) website explanation it says that ..."the Evening Watch is periodically divided into two watches. These are called Dog Watches because they "dog" the watch schedule for all divisions ahead by one watch period". It can be surmised that this may mean an action similar to the "feed dogs" on a sewing machine, although obviously the use of the term predates the use in the sewing machine. Dog watch Dog watch, in marine or naval terminology, is a watch, a period of work duty or a work shift, between 16:00 and 20:00 (4 pm and 8 pm).
Watch system standing 8 hours of watch followed by 16 hours off-watch. This schedule has been a fairly recent change to submariner work and rest routines. For nearly 45 years prior to 2015, submariners were on 18-hour days with 6 hours of watch followed by 12 hours off watch. The 12 hours off-watch were further divided into the first 6 hours being used for maintenance, cleaning, and entertainment; while the second 6 hours were usually for sleeping. Note that this arrangement resulted in one of the sections having two watches in one (24-hour) day, and there were no dog watches. Also, watch