Bandit, solo travelers are people who cruise without a romantic partner, they maybe single or married, what we are all talking about it escorted singles cruises,you must book a singles cruise with a Singles Agency, Ann Cambel has a singles cruise calender on this site, search for it.
You can also try some of the following agencys, Vacations to Go.com click escorted singles (they are my favorite) Crusing for Love.com, and Singles cruise.com. You will have a big group of singles, to hang out with. There are special singles only activitys and parties, but you can not these sailings directly with the cruise line, or normal travel agent or you will be excluded from the singles group!
You will find many singles in their 30 and up, some in their twenties too. We have at least 140 so far signed up for my Halloween cruise these are the most popular time. I think by the time our ship sales we will have about 200 singles. On a normal sailing there might only be a handful of singles. Book one you will not regret it you will have fun, fun, fun!