Reddit user /munkey_ninja18 has created a free homebrew 5e companion that covers the details of life at sea, as well as rules for combat, repairs, and the technical aspects of seafaring in D&D.
“Welcome to Korvalia! A realm of pirate seas and naval skirmishes. This homebrew material is designed as a supplement to 5th edition Dungeons and Dragons to aid in navigating naval combat and life at sea in a low technology magical world. Feel free to duplicate or repurpose this for your own campaign.
This is a supplement meant for those who are looking to run a campaign centered around a lot of sea travel, pirates, swashbuckling, naval combat, and a general disdain for landlubbers. It includes additional systems for naval combat which are cumbersome to add onto 5e unless seafaring is going to be a primary focus of your campaign.
In addition to some new rules and skill checks, the arcane ship crew is presented as an alternative version of the Acquisitions Inc Company Positions except specifically centered on the roles and duties of a ship crew. It is meant to provide a 5e party with more options while engaged in naval combat and to make naval skirmishes and general life at sea more unique and interesting. Enjoy!”
It’s a free download, so check it out: