If you dont want to make the leap to a Frigate, ive found a Brig of War to be a wonderful ship once youve gotten its copper plating and cotton sails added. She's got 32 cannons, yes, as many as a Frigate, but she's about half the size and quite manueverable. She isnt as fast as a frigate or sloop mind you, but she can take a considerable bit more damage than a sloop, and is almost as hard to hit. She also has a max crew of 200, putting it into the raiding category for all your shore party needs, and to top it all off she carries as much carge as the Frigate, and20 to 30 more tons than the largest sloops.
One thing i like about the BoW is how quickly you can tack over across the wind. Where most larger ships stall out headlong for a minute or two, the BoW can actually skid hard over if you do it right, avoiding the stall entirely. Give it a try!