Sam & Darren,
A wedding at sea performed by the captain would be very romanitic indeed -- the romance of the sea probably is its primary allure!
That said, there are a few issues that you might want to consider before making a final commitment one way or the other.
>> 1. Do you want your close friends to be in your wedding party? Also, do you want your immediate families to attend your wedding in person? If so, do you want these individuals to accompany you on the "honeymoon" phase of the trip? Will they be able to afford the cost of the trip, or will you have to pick up all or part of the cost?
>> 2. Who do you want to invite as guests to your wedding? Do you want the guests at your wedding to accompany you on the "honeymoon" phase of the trip? Will the invited guests be able to afford the cost of the cruise? If there are guests who might not be able to afford the cost, are you willing to assist them?
>> 3. Do you want to have a secular ceremony or a religious ceremony? (The ship's captain can perform only a secular ceremony.)
>> 4. Do either of you belong to a church, synagogue, or other institution of worship that has specific requirements (for example, a religious ceremony) for marriage? If so, how will you fulfill your religious obligations with regard to this marriage?
I suspect that the answers to these questions will shed some light on the suitability of a wedding at sea to your circumstances.
Congratulations and best wishes, whichever way you decide to go!