Like most things on the bb, this is not a new topic. Several years ago, on the first cruise I took out of Galveston, TX, I followed (exactly) the advice from Allen, N5AFV, on his various web articles. You can get a good overview here and links to more details as well: http://www.qsl.net/n5afv/cruise.html
Allen has been there and done that and I had nothing but success in following his recommendations. I had the license and the ship's permission--no problem. I have another cruise planned April 11-17 (listen for me on AO-51), but remember my first cruise "experience" like it was yesterday:
EL60
27.08.2007 1358 N5ZNL
27.08.2007 1358 N5AFU
27.08.2007 1359 W7JPI
27.08.2007 1400 W0SAT
27.08.2007 1402 XE1KW
EL51
28.08.2007 1320 N5AFV
28.08.2007 1321 N3YZ
EL45
29.08.2007 1418 WA2EHL
29.08.2007 1419 W7JPI
29.08.2007 1419 W0SAT
29.08.2007 1420 N7JK
29.08.2007 1420 KE5CWC
29.08.2007 1421 XE1KW
29.08.2007 1422 N5ZNL
I used an FT-51R and an AL-800 antenna. I plan to take an Arrow this time :-) 73, Jerry, K5OE