A family of fifth-generation sea captains has launched a new service to cater to medium-sized parties interested in cruising Casco Bay.

The Casco Bay Cat, a 46-foot aluminum boat built, owned and captained by members of Fogg’s Boatworks, set sail for the first time Friday. The vessel took six months to build at a cost of about $500,000 and can hold up to 49 passengers.

“There really wasn’t, and isn’t, anything in the bay quite like this,” co-owner Patrick Fogg said. “You have a lot of other older troop-carrying boats that people have turned into private transports or charter boats, but as far as a unique set-up where you can just have a big platform and a big cabin for people to be outside or inside and comfortable … this sort of covers all bases.”

Located on Maine Wharf off Commercial Street in Portland, Fogg’s Boatworks has about 20 employees. It is owned by Dennis Fogg and two of his sons, Patrick and Eben.

Patrick Fogg said the expansion is in response to a need in the Casco Bay market area for a more medium-sized charter service. He said the company received multiple requests last year for boats that could carry more than six people. The area has been increasingly popular as a destination for bachelor and bachelorette parties, as well as weddings and tour groups.

The price of the Casco Bay Cat charter is $350 per hour for parties of 20 or more or $250 per hour for parties under 20. They offer smaller vessels for parties of six or less for $100 an hour.

The company teamed up with an employee of Casco Bay Lines about three years ago to offer private charter and taxi services. Last summer, it began offering the services full time.

“When I was a kid, I had a floating hot dog stand out (on Casco Bay) and (ferry captain) Gene Willard called me up and said ‘Hey, this is a great idea and I want to help you out’ … 15-ish years later and we’re partnering up,” Eben Fogg said.

While Fogg’s Boatworks has only been on the Portland waterfront for the past 10 years, the company has been around since Dennis Fogg began the business as a ship restoration, repair and building operation about 35 years ago. Fogg’s Boatworks has a shop in North Yarmouth.

Patrick and Eben Fogg are fifth-generation captains and say being on the water runs in the family.

“We both grew up on the water and have been driving boats since we were 8, 6, 5 even,” Patrick Fogg said.

This story was updated at noon on June 15 to clarify the relationship between Fogg’s Boatworks and Gene Willard.