At this rate, you could fill the whole boat just by having people buy raffle tickets from various Chabad raffles.
Personally, I'm somewhat surprised that the first raffle did so well, as for many people, there are so many logistics of the trip that make it hard for them beyond the cost (people who follow different poskim regarding Shabbos and the fast times, people who can't go away for 2 weeks, people who can't be virtually unreachable for that long, people who have health-concerns with sailing through the Drake etc).