Can we go on a cruise?

Update 1: He said YES! :)

Update 2: Our booking has been confirmed! Now, next emergency -- lose like 20 pounds to fit into my favorite evening gown for a formal night. This one is more challenging, I am afraid.

My family usually takes an annual vacation together. Last year, we did not go anywhere because of Dad's surgery. This year, I found a great cruise to Bahamas in late August-early September (yeah, hurricane season but it works great with our busy schedules; I am biased, too -- my birthday is on one of those days). It's not as long or nice as a cruise we have taken before (it was Jamaica last time) but it's nice enough.

Because of the Labor Day weekend, only Dad has to take two days off. Guess what??? Even though he has plenty of vacation days, he is a creature of habit -- those days are taken for Christmas holidays only. So now we have a big project -- convince Dad-the-Workaholic that it's OK to take vacation days earlier this year; and it has to be done before prices go up and/or this cruise sells out. Come on, Dad, cooperate!!!

Any useful persuasion tactics out there?