Any crew is immediately divided in half, so half can be sleeping. That leaves 6 to 7 people to operate the ship. One must be the command officer. A second must be the watch leader. A third must be the engineer.
Any additional crew assist in sail handling and rotate on the deck watches.
The off-watch crew sleeps and is available for emergencies. Keith's letter suggests that Yale Iverson was not at fault in the sinking of the ship, but instead implicates the Alexandria Seaport Foundation for poor electrical work, presumably allowing the pumps to malfunction. I am also not inclined to defend the ASF's judgment and handling of the schooner's last year and her sale. All of the ship's needs and weaknesses were made known to Yale Iverson. He was provided with professional surveys of her condition.