"He's someone who is very creative," said Denise Pride, a Philadelphia public-relations agent who has helped Certaine document his work.
All his life he loved models, particularly cars, which he re-created down to brakes that worked when the foot-pedal was pushed.
Certaine turned out cars like a Detroit production line. But he built only a few boats, and just one ship: The namesake of an early Italian explorer who forever dwells in the shadow of a contemporary, Christopher Columbus.
Amerigo Vespucci - the man - was a sixteenth-century navigator, mapmaker, and explorer who sailed in service of Spain and Portugal. He's credited as the first to realize that North and South America were distinct continents, a discovery made on a voyage in 1501.
It's from Amerigo that North and South America get their names.
The ship named for Vespucci was built in Naples in 1930 and launched in 1931, a 26-sail, three-masted vessel with a steel hull longer than a football field. It was designed as a training ship and continues that mission today, traveling mostly European waters but also sailing to the Americas.
"Amerigo Vespucci conjures up memories of men-of-war from two centuries ago," according to Tall Ships America, a nonprofit education and preservation group. "Riding high in the water, with triple decks indicated by painted stripes, Amerigo Vespucci is a gracious 20th century goodwill ambassador."
Certaine was model-car crazy from the time he was a teenager in the early 1940s. He hung out at Center City hobby shops, devoured catalogs, and even staged exhibits of his work at banks and department stores.
It was in the late 1970s or early 1980s when he saw a photo of the Amerigo Vespucci in a catalog.
"I fell in love with it," Certaine said. "I cut the picture out and put it under my pillow. Every night before I went to sleep, I pulled out the picture and admired it."
In the 1980s the Amerigo Vespucci landed in Philadelphia as part of a celebration that featured tall ships. Certaine went to the dock and took photographs, knowing he could incorporate the details into a model.
By the late 1980s, as his eyesight faltered, he knew the time to build his ship was now or never. He began reading books on model-ship construction, eventually coming across an Italian author who had served on the Amerigo Vespucci - and now lived in New York.
Certaine got in touch. The author offered to have scaled instructions sent from Italy. Alas, when they arrived, the designs were written in Italian. So, working with an Italian-English dictionary, Certaine figured out the parts.
His was no prefabricated kit, with notes to insert Part A into Part B. Certaine cut his parts by hand, carving, bending and gluing the woods.
He began work in 1990 and for most of the next 10 years, "I was tied up with a jealous mistress," Certaine said.
Today the ship is docked in a glass case in the living room of his West Philadelphia home.
"It's museum quality," said Walter Bell, a longtime friend and a well-known jazz flutist. "You would think Oprah or Bill Cosby or somebody would get behind that. . . . This thing belongs in the Art Museum, in the Franklin Institute - the city should take advantage."
Bell, of Chestnut Hill, recalled that during the ship's construction, Certaine was obsessed with making sure the details were exact. When he needed certain woods to appear aged, he buried them in his yard, letting dirt and moisture do their work, then later retrieved the parts.
The problem now: What's next for the Amerigo Vespucci?
Certaine is frail, his fingers bent and legs unsteady, his face encircled by wisps of gray hair.
"I don't know what's going to happen to it," he said.
He lives with his sister, Vivian, in a rowhouse that's been in their family for decades. He had told her she could have the ship - but now she's battling her own health issues.
Neither has children or heirs.
Bell has been trying to come up with places that might be appropriate, and to generate publicity that may help find a home for the ship. He's sure there's an institution that would want to display the Amerigo Vespucci.
The challenge is finding that place.
"People flock around the Rocky statue and they don't even know about this," Bell said. "This needs to be shared."