From publisher blurb:
Heroic adventurers set off on epic quests that take them far and wide: across land, over the sea, and even sometimes through the air. But how do they find their way? By navigating, of course. While tales of finding the proper heading are often left out of the epics, there is no doubt that Jason and his Argonauts or wily Odysseus must have spent time charting their courses.
So too the brave adventurers must spend time finding their way, and while this is typically hand waved away or reduced to a few rolls, it can also serve as a deadly complication or the inspiration for new stories.
Compass and Sextant is a short PDF focused on navigation tools. It includes
Real world history of navigation
Navigation in a fantasy setting
Optional rules for rewarding expert navigators
Tools for running a nautical campaign, including a ships crew and tables for generating random islands
Four new magic items
Three new monsters