On Naval Manning (followup to CDR Salamander)

I never served on a Minesweeper, just drove an Amphib and a Cruiser. While at GQ everyone should be at a battle station I would think that for an extended operation, as I believe sweeping a channel would be, shouldn't that be modified so as to permit some portion of the crew to stand down on rotation? Also I am puzzled by the reference to "optimal manning" leaving no slack. The reason that naval ships carry a large crew is so that they can absorb battle loses. Look at the bridge team. During GQ you will have the CO, OOD and maybe a JOOD, even on a small ship. At the wheel you would have your best Helmsman, usually a Quartermaster and another QM at the chart table with the logbook. In addition there is the Lee Helmsman, possible a Boatswains Mate, at the Engine Order Telegraph, who really serves no purpose except to be there in case the Helmsman gets killed. Ships expect to suffer casualties in combat, otherwise they would be manned like merchants. While I know that the bean counters are pushing to minimize crew size the Navy we are discussing here had not yet been McNamaraed let alone Obamaed. If the Chief knew who was where on the ship then that information could have proven useful to a Board evaluating the loss and then after seeing who survived making recommendations. The most important part of any action is the "lessons learned." What did we learn from the loss of the Magpie?