Note also that the USNS Comfort was deployed more quickly to Haiti in 2010 (for an earthquake which had zero days warning) than to Puerto Rico, where the order was given seven days after the storm struck: https://www.usnews.com/news/national-news/articles/2017-09-2...
Predeployed for Irma. Then two of those ships went home after helping Florida... as maria was bearing down on PR they were sailing away in the opposite direction.