Longshoreman Howard Keylor knew when to unload a ship and he knew when to refuse. A longshoreman for decades on San Francisco Bay, Keylor could unload the contents of a ship’s hold as fast as anyone on the waterfront.

But he could also stand fast, lock arms, hold a megaphone and do nothing.

That’s what he and his fellow longshoremen did for 11 days in 1984, when the South African cargo ship Nedlloyd Kemba came to the port of San Francisco, its hold full of fruit, wool and sugar. At the time, the policy of racial segregation known as apartheid was the law in South Africa.

Much of the world was outraged by apartheid, but much of the world has a way of sitting back and watching from the sidelines. That was not Howard Keylor’s way.

“There are just certain things you do because you have to do them,” he said. “You do them without thinking. When something needs to be resisted, you resist.”

Keylor, one of the leaders of Local 10 of the International Longshore and Warehouse Union, stood fast and helped persuade his fellow longshore workers to do the same. He and his fellow members refused to set foot on the vessel. They set up a picket line to discourage anyone else from trying. There was a lot of yelling. But for 11 days, the cargo stayed on the ship.

Six years later, when freed South African leader Nelson Mandela spoke to a crowd of 58,000 cheering supporters at the Oakland Coliseum on the last stop of his U.S. goodwill tour, he credited the Bay Area longshore effort of 1984 with helping to bring down apartheid.

“I was just one of a whole lot of people,” Keylor said. “I don’t want to make a big deal about what I did.”

But his fellow longshore union members do.

“Howard stood there and exhorted the crowd to support us,” said his friend of five decades, fellow longshore worker Jack Heyman. “We totally blocked that ship. It scared the hell out of the South African government.”

On Sunday, Keylor’s 93rd birthday, Heyman and the rest of the union hosted a testimonial at the union hall in San Francisco celebrating their friend’s long history of good works. Keylor, the union said, is its oldest member. He got a plaque paying tribute to deeds done “in the best tradition of the ILWU.”

Ninety-three isn’t a round number, or even an even number, but it seemed a good time anyway to honor Keylor, who moved into a Castro Valley assisted living facility a few months ago following a stroke. These days, he reads a lot and watches TV a little. He speaks slowly and walks slowly. But he thinks quickly, even if it takes a while for his words to catch up.

“When you get to be my age,” he said the other afternoon, grabbing for each word as if it were a 50-pound sack, “nothing is OK. You adjust to the new reality. You try to survive. My advice? Don’t get institutionalized.”

Keylor, a native of rural Ohio, is a U.S. Army veteran of World War II, a survivor of the Battle of Okinawa, a Bay Area longshore member since 1953 and a member of its executive board. He was part of the strike at an Oakland glass factory in 1974, as well as a boycott of shipments to the military governments of Chile in 1975 and El Salvador in 1980. He was part of the West Coast strike of 2008. And he was part of the Occupy Oakland movement in 2011.

“A lot of other people stood beside me,” Keylor said.

Loading and unloading a vessel in the days before mechanized shipping containers was backbreaking, challenging and complex work. Success depended on teamwork, on knowing exactly what your fellow longshore worker was doing. Each vessel posed a different challenge, Keylor said. Unloading bars of steel was much different than unloading sacks of wool.

“Your life depended on the man standing next to you,” Keylor said. “Every day.”

For his 93rd birthday, what he really wanted — more than a testimonial at the union hall — was something Heyman, his frequent visitor, can’t supply.

“He wants me to bring him German beer and cigarettes,” Heyman said. “The doctors won’t let me.”

Steve Rubenstein is a San Francisco Chronicle staff writer. Email: srubenstein@

sfchronicle.com Twitter: @SteveRubeSF