I propose the addition of a captains handbook, available at port and sea.
Two things I want to see in here are:
1. Ability to write you own notes, personal ledgers, saved so when game is quit and reopened it still appears.
2. Rules of Engagement. I think every captain should be aware and have a guidelines for all rules of engagement of the sea, in open world and patrol missions. This helps players be aware of how battles work. Seeing how the devs are always tweaking join timers or other aspects of battle mechanics. It would be helpful to have a guidebook on current operations.
Some of you may have other useful suggestions of what could be added to a captains handbook.