PORTLAND – Visitors who boarded a replica of one of the three ships used by Christopher Columbus in his voyage to the New World marveled at its small size.

Because the 93-foot replica bobbed and swayed with the slightest movement of the water in Portland Harbor, some visitors Saturday had to grab onto something stationary to keep their footing even while the vessel was docked.

“It’s amazing that people lived and sailed on it. It’s like a cork bobbing in the ocean,” said Jane Kimball Foley of South Portland, who arrived with her family Saturday to tour the vessel.

The replica, which was built in Brazil 12 years ago, is operated by the Columbus Foundation, a private foundation based in the British Virgin Islands.

The ship travels from port to port. It was recently in Bar Harbor, where it did some filming for PBS, and sails to Hartford, Conn., after its five-day visit to Portland ends Sunday.

The original Nina sailed with the Pinta and the Santa Maria under Columbus, who was looking for a different route to India when he accidentally sailed to the Caribbean in 1492.

“I can’t imagine,” said Pete Davis of Pownal, as he stood on the dock Saturday and stared at the replica of the Nina. “We envisioned a much bigger ship,” he said.

Brooke Wright, a University of Michigan senior who is a deckhand on the ship, joined the crew for the summer. She sees parallels between her dream adventure on the vessel and Columbus’.

“Ordinary people can have adventures,” Wright said. “He proved to the world he could do it, that it was within the realm of human capability and ingenuity.”

The ship’s rudder is controlled with a hand-operated tiller, but whoever is at the tiller can’t see over the bow while the ship is underway. “Someone always has to be up front shouting directions,” Wright said.

Despite the vessel’s small size, “It’s a great sailing ship,” said Doc Kaiser, a member of the ship’s crew. It draws only 7 feet of water and has 32 tons of rocks in its hull for ballast, because it’s so top-heavy.

The ship is made of Brazilian hardwood, treated with tar and linseed oil. The original Nina was made of oak, according to Joe Ross, a deckhand who joined the crew in Cape May, N.J.