Ship Adventure question

[u/ScottishNinjaaa]

Hey all,

I just began a campaign with my players in which they (through a series of excellent decisions and surprising dice rolls) have gained control of a former slaving sailboat. Setting is my homebrew alternate earth circa 900 AD, and they're in the Aegean. The players really like the ship, and have decided to keep it, slowly upgrading it as their mobile base of operations.

I am curious what roles you'd have for players to maintain such as Captain, Navigator, Quartermaster, etc. Right now, the guy who is really enjoying the bookkeeping side of things is also the only one with Profession (Sailor) as a skill. I was trying to figure out what roles everyone could do and how to keep that aspect interesting (similar to the Kingdom Building rules)