I’m waiting for my ship to come in.

I hear it before I see it, shtetl melodies filling the air. As the Blue and Gold Fleet motors into the berth, the sound of a violin bowing over the prow hits the dock along with the bell of a trumpet and the bellows of an accordion.

The crowd of Jews waiting with me hoots and hollers, and the passengers wave at their friends on shore.

So begins Klezmer on the Bay, a sunset cruise that meanders from SBC Park’s McCovey Cove to Tiburon , stopping in between to pick up and drop off revelers. Four JCCs got together to sponsor it, and there’s something for every sense: a Jewish feast, salty-clean ocean air, impassioned klezmer sounds from the band Klez-X, stunningly clear views and frenetic bodies dancing to Old Country tunes.

The band is the centerpiece of the event, and Klez-X really kills. The stand-up bass and tiny drum set keep time like clockwork, making it easy for the audience to be on their feet most of the night. In fact, when the ship docks at the end of the cruise, many don’t want to leave the dance floor.

It’s kind of an aquatic Catskills, with violin, trumpet and accordion relentlessly turning out song after song. The crowd goes wild — they know the right jigs for these jams.

The crowd is a slice of Bay Area Jewry plus some surprises. Grey-haired “Marin-ers” wearing flowing ethnic prints. Russian-accented women dressed to impress, whispering among themselves and giggling. A sprinkle of younger folks sneaking outside to neck and commingle their Chardonnay with the cool breeze.

They all know when to waltz, when to hora, when to break into a kind of skipping-clapping dance that reminds me of a Hebraic conga line.

The surprise is a group of about 10 Japanese who are as knowledgeable of the dances and enthusiastic as anybody. Not Jews, they apparently read about the cruise and thought it would be fun. They laugh and waltz and seem to be captivated by the party.

This simcha on the water has its own lifecycle. First, the passengers get situated near the bar, on deck or close to the music, depending on their preference. They see their friends, they drink their first glass of wine. Then, somewhere between Alcatraz and Angel Island, the band starts its first set, a warm-up stretch of mostly instrumentals.

Then comes the nosh. It’s good stuff — salmon, salad and couscous with fruit, plus all kinds of knish. There’s some pushiness to get a plate, but everybody is able to have some nice portions and people are polite.

Before they have time to digest, however, people are up and dancing in a circle. The accordionist is singing in Yiddish and the beat quickens. Everyone is clapping, the wine and cocktails are flowing.

Singles are wearing little rose stickers so that they can mingle more efficiently. Everybody’s getting friendly.

Circles are circling within other circles, spinning around so fast that people have to be careful not run into the pillars of the lower deck. The ship is bobbing gently, but the bobbing and the spinning and the pulsing melodies — oy.

I’m feeling really warm and flushed. It’s a little more than I can take, and I stagger up onto the deck where the breeze helps straighten me out. We’re directly under the Golden Gate Bridge, moving slowly, and there isn’t a trace of fog.

The band is now in full waltz mode. I think of the history of Jews and boats — Noah’s ark, 19th-century immigrants crossing the Atlantic. This couldn’t be more different: We have no place to go, nothing to escape from.

Tonight we have a boat so we can pull back from the land where we work and live and sleep, appreciating that after all the Jews have been through, we have some fine food, some damn fine music and good company.

My seasickness calms down and I go back to the dance hall. We’re returning to San Francisco, and no one wants to face the last waltz.

Maybe when the Messiah comes he’ll bring a boat, some nosh and a band. If he takes too long though, maybe Bay Area Jews will have to charter another klezmer cruise ourselves — when the weather’s nice.

Jay Schwartz can be reached at [email protected].