April 28–The Embarcadero's aged piers are so integral to San Francisco's self-image that we forget how precarious they are, especially the ones that look robust but are structurally and seismically frail.

That's why if we want to preserve them, as we should, the smart approach is to treat them as works in progress. Works that might benefit by being used in ways that have been shunned in the past.

Or at least exploring whether such changes make sense.

This is the path being approached, warily, by the Port of San Francisco as part of its update to the city's waterfront plan. And though watchdogs are eager to sound the alarm, there's wisdom in pushing ahead.

The plan dates to 1997, when the Embarcadero was a much different place.

The double-deck concrete freeway that had walled off the waterfront from Folsom Street to Broadway was gone — dismantled after the 1989 Loma Prieta earthquake — but the Ferry Building hadn't yet come back to life. The Giants were designing their ballpark. The rebirth of Pier 15 as the Exploratorium was 16 years away.

You couldn't enjoy a cocktail and Cajun food at Hard Water on Pier 3. The idea that Pier 24 might someday house photography exhibitions would have been ludicrous.

Now all those things are in place, the byproducts of more than $1 billion in public and private investments from Pier 39 south to Mission Creek. It's a promenade that attracts city residents and first-time tourists alike, dotted with parks and plazas where you can take in the view and not spend a dime.

The catch is that perhaps half of the 15 surviving piers built between 1909 and 1931 need sizable investments if they're to endure as anything other than atmospheric relics. So the port has consultants studying how some might be restored without sizable public investment.

One alternative? To convert a pier or two into a hotel — a use expressly forbidden by city voters in 1990.

It's not a recommendation, merely a what-if scenario within a larger "feasibility analysis" discussed at two recent meetings of a subcommittee of the Waterfront Plan Working Group, an advisory board to the Port Commission. But the very notion of revisiting old edicts is stirring up complaints.

"They're going down the path of commercial use, which is a red flag," said Jon Golinger, a Telegraph Hill activist best known for running the campaign against the 8 Washington housing complex on the inland side of the Embarcadero that voters rejected in 2013.

"The port paid to develop a detailed analysis of hotel use, which is illegal currently."

Putting aside the moralistic dismay that piers built to serve the industrial waterfront might be considered for commercial uses, Golinger is right in that 1990's Prop. H banned hotels.

But it's disingenuous to suggest that the voters' will is sacrosanct and not to be questioned. Consider other ballot decrees from that time:

–An ordinance to recognize "domestic partners" — legal relationships between gay people, a forerunner to same-sex marriage — was overturned in 1989.

–Voters in 1997 wanted the Central Freeway to be rebuilt as an elevated structure connected to Fell and Oak streets, instead of replacing it with what now is Octavia Boulevard.

–Three years before the Loma Prieta earthquake, a ballot measure backed by City Hall power-brokers asked voters for permission to tear down the Embarcadero Freeway. The voters said no.

Our city — and our civil rights — would be poorer if these outcomes had endured.

Other cities allow hotels and even housing along their waterfronts, including such alluring destinations as Vancouver, British Columbia, and Boston. The key is to have full public access to the shoreline, with walkways along the perimeter and small docks for water taxis at a scale far beyond anything in the Bay Area.

In other words, there are no simple absolutes for what an urban waterfront should be.

This point was made at the last Land Use subcommittee meeting by Jennifer Lucchesi, the executive officer of the California State Lands Commission.

It's the commission's job to determine whether changes to port-owned properties are acceptable uses under the public-trust doctrine that governs California's shorelines. In the past, the commission has taken a conservative approach, but Lucchesi indicated there's interest in perhaps loosening things — a little bit — if the payoff is preservation of the remaining century-old piers.

"There is nothing in California like the Embarcadero. That might be an argument for taking a more flexible and creative approach" to allowing uses like hotels that help finance seismic makeovers, Lucchesi said. "There's an evolutionary nature to the public trust and how it accommodates society's needs."

Again, the study is just beginning. Port staff will lay things out to the subcommittee. Which may or may not make suggestions to the working group. Which is only advisory to the Port Commission. Which would decide if the idea should be taken to voters for a yes or no.

Ah, San Francisco.

"Studying the hotel option makes a good deal of sense," said Rudy Nothenberg, the former city administrator who heads the working group. "As long as we make it clear we understand that the voters ultimately will decide what to do."

In other words, approach the topic with an open mind. And a respect for the fact that our waterfront, like our city, has a future as well as a past.

John King is The San Francisco Chronicle's urban design critic. Email: [email protected] Twitter: @johnkingsfchron