The VTG hosted cruise on the Carnival Pride out of Long Beach, California has attracted tons of the younger singles that are fun, fun, fun. I am booked on that Halloween cruise Oct. 29th.
I think that the Carnival ships attract a younger crowd if that is what you are looking for.
Princess cruise lines attracts mostly couples in their 40"s on up. But if a group of Singles are booked on the ship then you have singles to hang out with.
I prefer cruising with a Hosted Singles group than cruising by myself with a friend.
The cruises up to 7days attract younger singles but if you book a 10 day on up you will find an older crowd.
I am a mature gal but I like hanging out with the 30's to 50's crowd.