Watch Bill Manpower: Meeting a Continuous Two-Person Damage Control Watch
A repair locker at a forward-deployed squadron must keep two damage-control watchstations manned continuously, 24 hours a day, in four-hour sections. Each section requires two qualified watchstanders, and a section begins every four hours around the clock, so a full week contains 42 sections. No one may stand more than five watches in a seven-day week, and one person cannot fill both positions on the same section. The leading chief currently lists 18 sailors as damage-control qualified. Before the next underway period, the operations officer expects that 20 percent of those 18 will be unavailable at any given moment for leave, medical appointments, and a scheduled school, and unavailable sailors cannot be counted on the watch bill. The chief's draft bill assumes all 18 are available daily; the executive officer has already rejected one version that put the same three sailors on back-to-back mid-watches.
1. How many watch slots must the bill fill each week, and how many qualified sailors must actually be available to cover them without breaking the five-watch limit?
Read the worked answer
Slots per week. Six four-hour sections occur each day, so 6 x 7 = 42 sections. At two people per section that is 42 x 2 = 84 person-watches per week.
Sailors required. Each sailor may take at most five: 84 / 5 = 16.8. A person is not divisible, so 16 sailors (80 slots) would leave four slots uncovered. The minimum available pool is therefore 17.
Rounding up, not to the nearest whole number, is the whole point of this step; 16.8 rounds down to 16 only if you ignore the four uncovered watches.
2. With 20 percent expected unavailability, how many sailors must be qualified to keep 17 on the board, and how many more does the chief need beyond the current 18?
Read the worked answer
Only 80 percent of the qualified list is usable, so 0.80 x N must be at least 17.
N = 17 / 0.80 = 21.25, which rounds up to 22 qualified sailors.
Check the current state: 0.80 x 18 = 14.4, so about 14 sailors are actually available against a requirement of 17. The command is roughly three watchstanders short every single day, which is why the draft bill keeps producing back-to-back mid-watches.
The chief needs to qualify 22 - 18 = 4 more sailors, not one or two. Note also that a sailor in a school pipeline cannot be counted as partially available; the 20 percent factor is an average, and losses tend to cluster.
3. During an exercise, 12 of the weekly sections will require a third watchstander. Does 18 qualified sailors suffice under the same 20 percent unavailability, and what is the new minimum?
Read the worked answer
New slot count. The base requirement stays at 84. The 12 reinforced sections add one extra person each, so 84 + 12 = 96 person-watches weekly.
Available pool needed. 96 / 5 = 19.2, so 20 sailors must be available at any time.
Qualified list needed. N = 20 / 0.80 = 25.
With 18 qualified (about 14 available) the command is short by roughly six people for the exercise and the bill simply cannot be met. The recruiter-style answer is 25 qualified sailors, or a temporary relaxation of the five-watch limit, which the executive officer has already refused to allow.