To kick off the role-playing in the game, I’m thinking of having every expedition open with the offering of pledges. Any player who wants to go on a voyage may speak up and give his character’s reason for voyaging, and offer pledges to other player characters to have them come along.
What can be pledged? Items from your Treasure pile (everybody starts with several items), points of Wealth, an oath to go along on the other character’s next voyage, marriage into the family, even a blood compact.
Why offer pledges? Because the character who leads a voyage, or has the most personal reason for voyaging, will likely get the biggest Renown increase if it’s successful. To tempt other heroes into coming along, possibly for less Renown, you have to offer something of value.