In this post I talk about how I've hacked together sea faring rules for my USR Sword & Sorcery campaign utilizing Sailing on the Seas of Fate by Chaosium and Zack S's Wavecrawl Kit.
I've modified how I roll for daily encounter in the following way; for every week of sea travel I roll seven d10's. Only events which get 2 or more results are considered and will come up in play sometime during the week. 3 to 4 matching numbers mean the event is significant and watery doom could be at hand.
The ten event categories are also further subdivided if they spurred decent ideas, but I have to say, custom tables for your game world are a lot of fun. But they take some time to lovingly craft. Fortunately the internet has all these resources available to help you out. Like the products I mentioned above, there are literary thousands of free PDF's available online which can help you make your own gaming tools.