Exactly!
Be patient, keep this in front of folks. It sounds like a good idea.
Most non-profits can't make a decision on something like this without meeting on it. It may take a few weeks to decide.
If I read your post correctly, all they have to do is have you come to a meeting and you'll handle everything from there? There's no commitment or minimum number of bookings expected.
Once the cruise is done, they get the donation made to the non-profit.