Spirit of the Sound


On a July afternoon, Capt. Paul Lepanto piloted the nation’s first hybrid research vessel as it departed its pier at the Maritime Aquarium of Norwalk for a two-hour public education cruise.
As the 63-foot Spirit of the Sound got underway along the Connecticut coastline, initially its BAE HybriDrive engines operated on ultra-low-sulfur fuel, similar to many other working vessels its size. But when the aluminum catamaran exited the close quarters of Norwalk Harbor, battery power kicked in and the new boat’s uniqueness was apparent.

The vessel completed almost all of its educational tour into Long Island Sound on electric power supplied by the rechargeable batteries. Lepanto enjoyed smooth sailing out of and back into the harbor.

“It’s a unique vessel,” Lepanto said as he navigated past Green’s Ledge. “I’ve been pleasantly surprised by its handling characteristics and how quiet it is.”

The Incat Crowther design allows the hulls to knife into the water at a narrow angle with only a 4-foot draft. 

Brian Gauvin

A student group was aboard to learn about aquatic life in the sound. Lepanto invited a few visitors into his wheelhouse, including Micah Tucker, general manager of the Robert E. Derecktor Inc. shipyard, which built Spirit of the Sound. No one needed to raise their voice to be heard.

“The starboard generator is shut down, and what you’re hearing right now is the engine-room fans. That’s the loudest thing on the boat,” Tucker said. Spirit of the Sound “also has phenomenal range because of the amount of fuel that it doesn’t use.”

When the Maritime Aquarium ordered its new boat, it wanted a platform large enough to accommodate an entire busload of students — 65 people as opposed to the maximum of 29 people who could fit on its previous boat. The aquarium asked for the greenest vessel that feasibly could be built, with clean energy, biodegradable insulation and noise reduction, said project manager Robert Kunkel, president of Alternative Marine Technologies (AmTech) in Stamford, Conn.

Capt. Michael McCarthy mans the controls in the wheelhouse.

Brian Gauvin

The result was an Incat Crowther displacement catamaran design, with a unique maritime application of BAE Systems’ hybrid power system, which needed careful modification to perform in a humid, salty environment. Solar panels on the top deck power the VHF radios. A 30-amp shore plug-in charges a 24-volt battery backup system, which powers computers while the boat is at the Norwalk dock.

For about 15 minutes underway, the engines burn ultra-low-sulfur fuel to charge the two banks of seven Corvis Energy batteries. After that, Spirit of the Sound can sail for hours on emissions-free battery power. Cruising speed is 12 knots. A typical operation speed during an educational run is 4 to 6 knots. The captain slows to 1 or 2 knots when dropping a dredge.

“It’s the first time that the BAE system has been used as the propulsion system and not an auxiliary system,” Kunkel said. “The BAE system was already in use in roughly 4,000 buses around the world, and all that we needed to do was marinize the system and get U.S. Coast Guard approval with all the safety and redundancy.”

The battery compartment is located aft. It has its own built-in firefighting system, and the air inside the compartment is changed every minute. To avoid overcharging the batteries, the system automatically shuts down when the batteries reach 83 percent of full charge. When the batteries decline to 27 percent, the main engines automatically resume charging.

LED lighting is used throughout the vessel, from navigation lights to classroom fixtures to lighting in void spaces.

For the pilot, handling is somewhat unique because the electric motors have no forward or reverse gearbox. The electric motors simply spin either one way or the other with no delayed reaction, sound or vibration. When the captain moves the throttle, the boat goes instantly and does so quietly.

Capt. Bob Scinto uses a Muir electric winch with 3/4-inch line to deploy an otter trawl net from the stern of Spirit of the Sound. The catch results are recorded and passed on to researchers.

Brian Gauvin

“One of the most difficult things we ran into is the human resources issue of seasoned captains really depending on engine noises and old-school methods as to how it was maneuvering and how the engine is doing,” Kunkel said. “This motor reacts more quickly.”

The Incat Crowther catamaran design provides stability, allowing the designers to increase passenger capacity on a 63-foot-long boat. Each hull enters the water at a narrow angle at the bow, with only a 4-foot draft. Tucker called it “a knife blade cutting through the water instead of a big box.”

Spirit of the Sound’s regular sailings include fisheries surveys, for which the scientists asked for quiet, plus marine life study cruises, seal-watching tours and twilight osprey cruises. The vessel primarily operates in relatively open water in or near the sound, and sea trials were purposely conducted in conditions as harsh as 40-knot winds and 8- to 10-foot seas. Nearer to shore, the crew must cope with tight spaces as it undocks near the Norwalk River estuary, transits Norwalk’s Washington Street drawbridge and navigates past treacherous obstructions including two ledges and rocky areas along Sheffield Island.

Each hull of the catamaran houses a variable- speed diesel generator that is part of the BAE HybriDrive system.

Brian Gauvin

“On the weekends in the summer, it’s a busy, busy harbor. At that island we get a little bit of current that funnels through there, and we get a lot of traffic,” said Travis Mingo, the boat’s chief captain. Spirit of the Sound “turns on a dime. It stops on a dime. The visibility from the pilothouse is exceptional.”

Included in the Furuno advanced electronics package, monitors on the console show the captain an array of navigation and engine-performance statistics. If the vessel ventures into shallower water to view mammals, depth under keel becomes a high priority for the captain. Rpm, oil pressure, temperature and speed over ground are available in the wheelhouse at a glance. The two 14-inch monitors are customizable in real time to show what the captain deems vital for the waterway.

“I like the iPad type of feature where you can move around with the touch of a finger and zoom. It’s very user-friendly,” said Capt. Bob Scinto, who was serving as mate on the July cruise. “If we want to split the screen, if we’re out watching seals, I might want to see the depth on one screen and the radar and navigation on another split screen. You can overlay the radar right on your chart.”

Two banks of seven 600-volt lithium ion batteries power the hybrid engines.

Brian Gauvin

The science-ready aft deck includes an A-frame and dive platforms. Nearby is a Muir SD150 drum winch. While most marine winches run on a hydraulic system, Spirit of the Sound’s stern winch is electric and can manage 2,200 pounds of bollard pull. During educational sailings, it is used to lift a trawl net that collects fish-population samples. During research voyages, the winch may tow a 2-foot-long bio-dredge box or a remotely operated vehicle.

“It’s a three-phase electric winch, so it has a pretty big electric motor on it. We designed the winch to be large enough to tow some of the larger hydrographic survey equipment,” Tucker said. “Here we have an abundance of electricity, and you don’t have to worry about leaking hydraulic fluid and so there is no environmental impact. All you need is a cable and this pendant control.”

The floating classroom is Wi-Fi enabled, and students can view images of the navigation electronics on their indoor monitors or on smartphones.

Kunkel said Spirit of the Sound could be a template for future vessels with a variety of uses. He said other ocean research and tour organizations have expressed interest. With modifications, in particular substituting a reefer box for the classroom, Kunkel is promoting a similar hybrid catamaran design as a green means of transport for Connecticut farm produce to nearby coastal cities.

By Professional Mariner Staff