Alcatraz Island closed this week after damage to the island’s main ferry float made its primary access point unsafe, according to newly reviewed public records that shed light on the abrupt shutdown of one of San Francisco’s best-known tourist attractions.

The permit authorized Alcatraz City Cruises to reinforce the three remaining piles with internal rebar cages, grout and anodes. The work was ordered to be completed by April 29.

The records answer a question left open by the brief public notices announcing that Alcatraz was closed for dock repairs. They show that the problem was more specific — and more serious — than a routine maintenance interruption. Structural damage had compromised the island’s main ferry access.

The emergency work, however, does not appear to be the end of the matter.

At a BCDC meeting on April 16, Executive Director Larry Goldzband said the trouble began after Alcatraz City Cruises disconnected the permanent float for routine maintenance and replaced it with a temporary float. 

He added that BCDC had granted an emergency permit “to strengthen the three remaining piles” and expected to receive “a routine permit amendment to fix the entire structure.”

That does not mean Alcatraz will definitely close again. No agency has announced another shutdown. But the work permit suggests that this week’s closure was the first stage of a larger repair problem, not the whole of it.

The emergency permit is narrow in scope. It allows temporary reinforcement work at the ferry float and requires Alcatraz City Cruises to submit a completed permit application within five working days, indicating that regulators viewed the approval as an urgent stopgap rather than a permanent fix.

Even after the current repairs are finished, officials are preparing for a separate permit process to address the structure more permanently.

Megan Munce contributed to this report.