AMSTERDAM (AP) - So there we were, sipping shiraz at sunset and minding our own business, when there was a rude rap at the window. And then a hiss.
''Hullo? Goeiemiddag!'' I said, affecting my best Dutch greeting as I spun around.
''Honk!'' responded the intruder: a handsome white swan pecking at a porthole of our rented houseboat on the Amstel River and hoping for a handout.
That kind of thing happens when you bunk on a barge, as we did on a recent getaway to Amsterdam. Sure, we considered more conventional lodging, but hotel, schmotel. In this dreamy European capital laced with canals, there's water, water everywhere, and you might as well stay on some.
We weren't sure what to expect when we booked ourselves onto one of the city's hundreds of houseboats.
Would it rock back and forth, or bob up and down? Would we get a hot shower and a decent night's sleep? Would it smell like fish? Would we bump our heads? Would we get cabin fever, or worse, become seasick?
All our fears were unfounded - and every expectation was exceeded.
Aboard the Verwisseling (''Exchange''), a 130-year-old steel-hulled barge that once hauled wood in and out of Amsterdam, we enjoyed the kind of funky holiday that's guaranteed to float your boat.
Amsterdam's waterways, including the Amstel River that sluices through the city, are lined with an estimated 2,500 houseboats. So large and unruly is the flotilla, overwhelmed officials have slapped a freeze on the construction of any new moorings.
Barges became a popular alternative in cramped Amsterdam during a housing crunch in the 1960s. Then, it was a bohemian lifestyle and a bargain. Today, it's mostly a yuppie subculture, if only because boat maintenance requires deep pockets.
Some of these vessels are crafted from oak or teak; others from steel, concrete or prefabricated materials. Some are irreplaceable bits of floating history; others are abandoned or in need of major repairs. A few are just weird, like the ''Cat Boat'' on the elegant Singel canal, a floating refuge for hundreds of meowing strays.
Fortunately for visitors, some of the very best are for rent, and at prices on a par with three- or four-star hotels. And because they're both heated and air-conditioned, you can book yourself aboard year-round.
Ours was spacious enough to comfortably sleep six adults, and it was remarkably well-equipped. The kitchen had a stove, oven, microwave, refrigerator, freezer, dishwasher and even instant boiling water on tap - handy for coffee, tea or soup.
The common living area featured a comfy L-shaped couch, lovely live orchids, a flat-screen TV with DVD player, a stereo and enough windows and portholes to watch life on the river float leisurely by. And the bathroom had a huge jetted hot tub, a rain shower, and a laundry closet containing a washer and dryer.
Getting aboard these things is a snap, with no clambering required: Just step off the curb and onto the boat.
Getting inside can be a bit trickier, especially for people with disabilities: You enter through the cabin, but then have to negotiate a short but virtually vertical ladder to gain access to the hold.
Awaiting us on the dining room table were four wine glasses and a complimentary bottle of red. Outside, through one of the brass portholes, twinkled the lights of the famous Magere Brug, or Skinny Bridge - one of Amsterdam's most beloved spans.
That's surely one of the nicer aspects of staying on a barge: sipping the adult beverage of your choice while drinking in one languid, liquid view after another.
Although our barge moved slightly if a large passing tour boat or commercial vessel kicked up waves, most of the time you could barely notice. That might not be the case on smaller houseboats, which might be more easily knocked around.
And while there's generally ample head room, there are low ceilings in some spots even aboard a bigger boat like the Verwisseling. I knocked my head a few times before making a mental note of where I'd better watch it.
Security can be another drawback. Because it's at street level, a boat is easier to burglarize, so it's best not to bring aboard valuables.
Houseboats are different from hotels in other ways: They're self-catering, so there's no mini-bar (unless you stock the fridge yourself), no room service, and no maid to make your bed, though the owner is likely to pop by with fresh bath towels.
And like self-catering apartments, you have to pay a nonrefundable deposit in advance - typically 35 percent - and fork over the rest in cash upon arrival. That can be a little jarring to the uninitiated.
Smoking is forbidden or confined to the upstairs cabin on nearly all barges because of the fire hazard.
You also may have to forgo an Internet connection. We were supposed to have wireless access, but the miscreant tenants who preceded us stole the router.
One last caveat: Don't leave the portholes open.
Frank Jonckers, the affable owner of the Verwisseling and two other Amsterdam boats, says an entire family of swans once got in through an open window, only to panic when they couldn't get out, breaking glassware and soiling the boat as they flapped around. (Sure enough, we found a few telltale feathers when we swept up.)
None of the above should steer you away from the tranquility and sheer beauty of a barge.
A boat is a great place to come home to after a long day of sightseeing. It can also be a unique venue in which to entertain: I was in town to run the ING Amsterdam Marathon, and the barge comfortably accommodated 10 friends and colleagues who joined us aboard for a post-race pasta party.
One of our nicest moments was spent outside, up on deck in the bow with scarves flung around our necks, raising our coffee cups to passing vessels: a goofy bunch of ''Pardon me but have you got any Grey Poupon?'' posers proud of our boat and pretending it was really ours.
You couldn't spend a more quintessentially Dutch holiday if you slept on a bicycle.
If You Go ...
HOW TO BOOK: A number of companies rent barges. A good place to start is Houseboat and Apartment Hotel Amsterdam, (http://houseboathotel.nl). You can also deal directly with a boat owner, which can get you a 10 percent discount, but it may be difficult to ensure he or she is reputable.
HOUSEBOAT MUSEUM: There's lots of lore about barge life through the centuries, and you'll find it under one roof at the Houseboat Museum (www.houseboatmuseum.nl/uk/start1.html) on Amsterdam's Prinsengracht canal.
TOUR THE CANALS: Several companies offer tourists lovely rides through Amsterdam's web of waterways; see (www.amsterdam.info/tours/canalcruise/) for details. We chose the hop-on, hop-off option, which costs $23.50 for a 24-hour ticket and drops you at some of the Dutch capital's major attractions, including the famed Rijksmuseum and the Anne Frank House.
SIDE TRIPS: Stick with your ''water wonderland'' theme and hop a train to the harbor town of Enkhuizen, a world maritime center during the heyday of the Dutch East India Company in the 1800s. There, you'll also find the Zuiderzee Museum: (www.zuiderzeemuseum.nl/?language).