I have invented and spread the word of the Poseidon Curse.

That curse dooms any vessel that is boarded by a visitor bearing no gifts. It may be only a bag of chips or a bag of (desperately needed) ice. It could be a bottle of wine, or a few bottles of beer. Even a gallon of Poland Spring water.

According to my invented curse, if the boat sinks, goes up on the rocks or even goes off course for the next 20 years, that calamity can be forever blamed on the empty-handed guest.

The Poseidon Curse was developed over the past three weekends spent aboard the Daybreak, a vintage Catalina sailboat that tied up at the Rockland Public Landing to celebrate first the North Atlantic Blues Festival, then the Maine Lobster Festival. Rockland never looked better.

There is a dark cloud behind every silver lining, of course.

Once the word spreads that there is a sailboat tied up at the public landing, friends you haven’t seen since high school drop by. You can tell the quality of a friend by what he carries in his hands as he steps aboard. (Women don’t have to bring anything but themselves.)

I doubt that anyone keeps track, but I would bet that there were more pleasure boats in Rockland Harbor, especially at the Landings Marina, for the festival weekends than at any other time in its history. I know it sounds silly, but it looked like Newport, R.I.

When the sun rose for the past few weekends, it must have thought it was in the wrong place when it looked down at Rockland Harbor. The Lime City and its expansive harbor have entered some sort of alternative universe.

A very few years ago, the harbor was dominated by the sights, sounds and smells of the fishing fleet. The broad-shouldered O’Hara fleet seemed to take up half the harbor. The sardine plants took up most of the rest, along with the SeaPro fish processing plant. Maybe a half-dozen sailboats owned by pioneers such as Dennis Healey and Helen Barnes moored in the harbor.

Main Street reflected the harbor and catered to the fishermen. If you were looking for trouble, Rockland was more than willing to oblige.

As the fish landings hit bottom, the city soon followed. The O’Hara fleet left, the sardine plants closed, and the fishermen disappeared to Alaska, Fall River or some other businesses. For years, the most familiar sight on Main Street was plywood covering windows and doors, hiding the businesses that closed and left.

In a generation, the city has changed and been reborn as an art and boating center. There are more art galleries than bars, for heaven’s sake.

First the North Atlantic Blues Festival filled the public landing July 20. Then the rejuvenated Maine Lobster Festival took over the area last weekend.

It was standing (or mooring) room only at the public landing float for both events. Power boats and sailboats from Canada to Connecticut vied for space along the precious docks.

Those lucky enough to find space at the dock could sit back and hear Jimmy Vaughan, Deb Coleman, Bo Diddley or a host of bluesmen without leaving the boat. All right, if you were a zealot, you could buy a ticket to the grounds and actually watch the acts. The blues festival was canny enough to place the back of the stage to the public landing.

Two weeks later you could hear the sensational Dwight Yoakam (in Rockland!) on Friday night, and lie back Saturday night and be serenaded by the surviving members of the Marshall Tucker Band and watch the moon come up over Vinalhaven.

It simply does not get much better than this.

Pass the chips. (We are out of ice again.)

Send complaints and compliments to Emmet Meara at emmetmeara@msn.com.