WARSAW  Two dozen homeless men are building a ship to sail themselves around the world at the St. Lazarus Social Pension here, in the yard of a former tractor factory. Sparks fly from the rusty 55-foot hull as they weld it into form, even after losing the priest who led and inspired the mission.

These men with sharply lined faces and blurry, old tattoos have set out to prove their seaworthiness, and to prove that they have some value to society, even if society has largely written them off.

“Some people smack themselves in the head when they hear, and probably think we’re crazy,” said Slawomir Michalski, 51, who was a welder in the famous Lenin Shipyards in Gdansk and joined the strike led by Lech Walesa in 1980 that helped shake the foundation of Communist rule in Poland and the entire Soviet bloc. It was a singular moment in Polish history and one that adds resonance to tales of shipbuilding here.

But their story strikes deeper chords because, for all the modern tools in the building and corporate sponsors providing the raw materials, their endeavor echoes mythic themes of escape, adventure and redemption that can seem out of reach in a world of biometric identity cards and debt-collection agencies.