The cruise coin mechanics are explained in the guide, here:
https://forums.storm8.com/showthread....79#post1143479
Additionally, you might find
the rest of the guide helpful, if this was your first cruise. Please let me know if you have any other questions or if it can be improved, hope this helps!
The goal is there for those who did complete the event. You have 8 days, after the cruise is done, to do the 2nd part of the quest, which is to bake one of the wedding cakes. The extra time is for folks who did finish. I think you may also be able to purchase the Groom with gems during those 8 days? At least, some folks talked about being offered that during the last cruise; I'm not sure how long the offer lasted.