Hey Frank,
I forgot to add: You had mentioned about keeping powder dry aboard ship; I am not sure, and being no expert either, but I would assume that humidy and moisture would be a part of everyday, nay, every moment, life at sea. So keeping powder dry would be of a priority seems to me. I know that black powder will soak up moisture out of the air even in your living room over time. I have had paper wrapped rounds, blank charges for my musket, go bad in an open cardboard box after sitting on a shelf for a year or so.

But anyway, as for shipboard problems; I just finished reading the great and touching book, "Last Flag Down", about the life of the last Confederate Raider to operate on the high seas, the CSS Shenandoah. In this book the authors quoted extensively from the log of Lt. Conway Whittle, Jr, the Exectutive Officer and the one who really ran the ship. In one entry Lt. Whittle mentions the fact that his Ship's Carpenters finally finished building a special wooden room for keeping their powder dry. I would assume it was a thick walled, almost airtight thing. But found the mention of it interesting. Just thought you might find that interesting.
Take care,
Dave
Alabama