M/V CAYO LARGO: From Narragansett Bay to the Caribbean islands


One delivery, two ferries: La Plena sits atop Cayo Largo. (Courtesy Blount Boats Inc.)

The delivery of a new 300-passenger ferry for the Puerto Rico Maritime Transportation Authority on July 23 was an unusual event: the 165-foot boat arrived in Fajardo, Puerto Rico, with a piggyback passenger, the first of four 45-foot water taxis for San Juan’s transit system.

Both vessels, M/V Cayo Largo and the 49-passenger M/V La Plena, were built by Blount Boats Inc. of Warren, R.I.

Cayo Largo has a beam of 46 feet and is 96 gross tons. The propulsion system consists of four MTU 12V4000 M60 diesels rated at 7,080 hp connected to Twin Disc MG6848SC 2.5:1 reduction gear units that power the four Rolls-Royce four-blade bronze 56-inch-diameter propellers. “The diesel engines have been D-Rated from 1,850 rpm to 1,600 rpm for longevity,” said Robert Pelletier, Blount’s vice president. “The operator can run the boat wide open all the time, all day, with no limits on the throttle.”

The boat operates on runs of about one hour and 10 minutes to the islands of Vieques and Culebra at a cruising speed of 16 knots, which is 6 knots faster than PRMTA’s existing ferries. Fuel economies on slower crossings are possible “by running the two outboard engines and letting the inboards just rotate the props,” Pelletier said. The ferry’s onboard electrical power is supplied by two 55 kW diesel generators by John Deere.

Cayo Largo has diesel fuel capacity of 9,000 gallons and storage tanks for 1,000 gallons of potable water and 1,000 gallons of gray water. The boat can carry 300 long tons of cargo, including vehicles; to deal with the one-foot tidal difference at the piers it is equipped with a ballast system to help vehicles on and off the boat. The ballast tanks can carry 114 long tons of water weight, or 32,000 gallons. PRMTA uses fresh water for ballast to minimize discharge considerations.

Cayo Largo, which has a steel hull with an aluminum superstructure, was built to U.S. Coast Guard Subchapter K regulations and according to Germanischer Lloyd classification rules. Draft was an issue at the docks, so the boat was designed to draw 7 feet (maximum draft is listed at 8’7”). Other design factors met the 100-mile ocean certificate for cargo ferry service requirements and compliance with the American Bureau of Shipping’s structural hull specifications for the intended service. Since the boat’s route is “out in the ocean where they can get swells, seakeeping was also definitely an important design factor,” according to Pelletier.

Although rated for 300 passengers, the boat is equipped with 380 seats. Turnbull aircraft-style seats are used in interior spaces and there are dinette-style booths on the upper deck. There is no snack bar, but Blount’s design provides two areas on the main deck for installation of soda and coffee machines. There are lockers and racks for luggage, and on an unusual note there is a mortuary locker with space for two caskets. The pilothouse is full width, with wing stations.

Cayo Largo was the 322nd vessel built at Blount Boats and the 22nd built for the PRMTA, or its forerunners, in a remarkable relationship that goes back almost 50 years. Blount is also building a 75-foot aluminum 150-passenger ferry for the Catario-Old San Juan-Hato Rey route. The Subchapter T vessel will be powered by MTU 8V2000 M72 main engines rated at 965 hp at 2,250 rpm for a service speed of 18 knots, with 30 kW John Deere gensets. Delivery is scheduled for January.

Categories: Maritime News