Mystic — Hidden away in the hold of the Charles W. Morgan, where barrels of whale oil were stored during its long voyages, is the modern equipment needed for the upcoming voyage.

The Morgan that leaves the Mystic Seaport on Saturday will look like the ship that was first launched in 1841 but will be equipped with generators, high-capacity pumps, electrical panels, lighting, marine toilets, plumbing, batteries, and sewage holding tanks. A modern safety public address system and a gleaming steel fire ax are attached to a wall in the hold next to an original support beam.

One day last week, Quentin Snediker, the director of Mystic Seaport's shipyard, climbed down into the hold and past tables of valves, fittings and tools as workers installed some of the final items needed for the voyage. Much of the equipment is located in one small room.

The Morgan will be towed to New London on Saturday before leaving on a summer sail to such stops as Newport, New Bedford and Boston.

"To take a priceless artifact like this out we have to equip her to modern standards of safety," Snediker said.

Snediker explained there were several principles that guided the installation of equipment not found on the Morgan during its 80-year career.

First and foremost is protecting the historical integrity of a ship that is the last of its kind and a National Historic Landmark. This meant installing the equipment in modules that can be removed after the voyage without affecting the ship's original structure.

The equipment, Snediker said, is needed "to meet our obligations to protect a priceless artifact and be in compliance with modern standards of safety."

"We've made some compromises, but nothing we've done is irreversible," he said.

One diesel and two electric generators will run the pumps, which Snediker said can handle any emergency and supply a fire-suppression system.

A modern marine sanitation system, which includes modular toilets and holding tanks so there is no discharge of used water into the ocean, are needed to accommodate the up to 60 on board at any one time.

Safety equipment also includes inflatable rafts, life jackets and a modern navigation suite with radar and radios.

The ship, though, has not been modified to meet all Coast Guard requirements for carrying passengers because that would have entailed making structural changes to the ship such as installing watertight bulkheads that would have "compromised its historical integrity," according to Snediker.

Instead, the Coast Guard will deem the voyage a "marine event of national significance," which exempts it from some modifications. It will also be termed a dockside attraction and be inspected at each port.

When the ship returns to the Seaport in August, shipyard workers will begin the task of removing the modern equipment, the largest of which have been custom-sized to fit through the hold. The ship will then be back in its historic condition. The bilge pumps and electrical and lighting systems will remain.

j.wojtas@theday.com