Just some feedback for planning:
A really great idea! But one week sounds quite a short time. Ten days sounds better, 2 weeks would be best, so that there wouldn't be a feeling in the end that it stopped just when it had started.
We are arranging our own 'Once In A Life Time Diving Adventure In Caribian:
Our diving club is going to Caribian in Jan 2011. 2 weeks sailing in a fast sailing ship, fishing and diving. I and 2 other freedivers with 14 scubadivers and the crew. We will learn to sail, too, and we will do sailing etc. job on the ship. We will visit many islands (Tobaco, Bonaire etc.) After sailing we will just freedive and relax 1 week on some island.
From Europe it's so far away, so when we will finally get there, then we will stay a bit longer. Planning started 1,5 years before the trip, so we have much time to make arrangements. It's not so expensive as it sounds. In fact it's about the same as a normal 2 weeks diving trip to a some good place at the same distance.
Our plan with some pics from a trip on the same ship and area: ABC-sukelluspurjehdus 2011