Full disclosure: the author has had a personal experience with this particular brand of swashbuckling bachelor party. Admittedly, we had a blast, but it was because everyone aboard the noble vessel embraced the sheer corniness of the event. Though there are a number of pirate-themed bachelor parties available for you lusty adventurers all over these United States, the Inner Harbor in Baltimore offers the perfect mix of bay access and white-bread suburban weekenders to allow such an endeavor to flourish.
Unless you and your boys are teatotalers, you'll likely want to sign up for a Bring Your Own Grog (B.Y.O.G.) cruise. Not to get your hearty hopes up, but when we went on our cruise, there was a bachelorette party aboard as well. Though none of us swashbucklers plundered any booty, perhaps ye scurvy knaves will be a bit luckier.