Morrelli & Melvin | Multihull Design - Engineering - Brokerage Morrelli & Melvin Yacht Brokerage - Specializing in Sail & Power Multihull

Harbor Express 65 Commerical Power Catamaran

Operating in Boston Harbor, the ferries "Island Discovery" and her sister ship" Island Expedition" are among the first boats in the 65 foot range to secure US Coast Guard sub-chapter K certification for 200 passengers.

By reducing the weight of the structural materials M&M achieved a 30% improvement in the passenger payload for this size boat. These Boston boats carry 60 more passengers than the typical 149 passenger limit of USCG sub-chapter T certified boats currently built in this size range.

Time, money and resources were tight. This effective transportation solution was designed in less than five weeks. Boat builder, Island Boats out of Western Louisiana, and the design and engineering firm of Morrelli & Melvin worked together quickly to optimize propulsion, decrease drag, reduce structural weight and maximize payload.

Experience and resourceful applications of aluminum hull design and modern propulsion systems moves the 200 passenger payload at 22 kts using 1.9 gallons of diesel per nautical mile. There is an added advantage of commuting by water; taking the boat trip 20-35 minutes between stations is significantly faster than driving and parking a vehicle during rush hour.

Island Discovery and Island Expedition are products of collaboration between Water Transportation Alternatives and Massachusetts Bay Transportation Authority. Harbor Cruises, LLC operates the boats that serve local cities and six of the Boston Islands in the local National Recreation Area.


Length Overall
65 ft 11 in / 20.10 m
Length at Waterline
62 ft 6 in / 19.07 m
Beam 20 ft / 6.10 m
3 ft 6 in / .99 m
Displacement 89,500 lbs / 40,597 kg
Maximum Speed (Full Load) 23 kts / 26 mph / 43 kph
Cruising Speed (Full Load) 20 kts / 23 mph / 37 kph
Engines 2 Detroit Diesel Series 600 HP each
Propeller 32 in x 35 in 4 Blade
Material Aluminum
Builder Island Boats, Louisiana


Passengers 200 (US Coast Guard Sub-Chapter K certification)
Operator  Harbor Cruises, LLC