1st dog watch: 4pm to 6pm.
2nd dog watch:6pm to 8pm.
Set so that when standing traditional 4 on, 4 off (that's right, 4 on and 4 off running the ship and "working in between": maintaining the ship during your daylight hours off watches - except your Sunday afternoon watch which you got OFF) the watches "rotated" every day: midnight to 4am, sleep and breakfast, 8am to noon (lunch then work
to 4pm), 4pm to 6pm (first dog watch), dinner, then 8pm to midnight. The next day 4am to 8am, breakfast and work
to noon, noon to 4pm, work and dinner to 6pm, second dog watch to 8pm, then sleep to midnight. Then repeat . . . ad nauseum.