There are 3 pelagic trip operators in Cape Town - Cape Town Pelagics, Anne Albatross pelagics and Zest for Birds.
I am personally involved with the latter, so perhaps my comments will be a little biased. Nevertheless, I doubt any of the operators will have schedules extending into 2015 already. All of them will currently only show trips up until the end of 2014 for now.
The 3 operators work slightly differently. The first 2 use small game fishing vessels for their trips (about 35-40ft vessels) where they take 7 or 8 passengers and 1 guide on the trip. We, as in Zest for Birds, operate slightly differently in that we use a larger vessel (66ft vessel) and take a maximum of 12 passengers with 3 or 4 guides on board. Because of our larger vessel, we suffer less from cancellations due to weather and sea conditions as our boat can easily handle slightly rougher weather (although we also aren't stupid and don't go out when conditions are not safe). If one is susceptible to seasickness, a larger and more stable vessel might also be slightly better. The only downside is that it is slightly slower than the small game fishing vessels.
Anyway, whichever operator you decide to go with, I cannot recommend a pelagic trip out of Cape Town highly enough. I recently hosted Hadoram Shirahai, one of the world's top seabird experts, on one of our trips and, at the end, he said it was the best one day pelagic trip he had ever done in the world...! Quite a nice thing to hear about pelagic birding in the Cape from someone of his calibre...!
I do post short reports and photos of most of our trips on my blog, so if you are interested in having a look, please pop through to
http://hardakerwildlife.wordpress.com/. You'll have to wade through some of the other non-pelagic posts to find the reports, but maybe you'll find something else of interest in there anyway...
Enjoy the planning!
Kind regards
Trevor