That picturesque expanse of water - a mere four city blocks across in one spot and 15 stories below from the top of the bridge - defines our city and is an integral part of our lives. A trip out on the water can be restorative, enlightening, exhilarating and romantic. What follows is a guide to the many ways to enjoy the beautiful bay in our back yard.

If you ride the San Diego Bay Ferry often, you're likely to see the seal that lounges on Buoy 22 to your right as you head toward San Diego. "Some of the captains call him Fred," says ferryboat Captain Jennifer Keller. "Although I think she's a girl. But you won't see her lounging on the buoy if the tuna boats are unloading. She's guaranteed to be barking for a handout over in the fishing harbor."

For three years, Capt. Keller has piloted boats for San Diego Harbor Excursions, which operates sightseeing and dining cruise services along with the ferry and water taxi operation. And Keller's captivated by the job. "I'm constantly meeting new people, spending time outside in a quiet, natural world, watching all the harbor activity - and working with a great crew. I can't imagine a better way to make a living."

Keller's outgoing personality and love for the bay make her an ideal tour guide. She recommends riding the ferry at night when the downtown lights reflect on the still waters. "The winds die down and there's less harbor traffic in the evening so the waters can form a near-perfect mirror," Keller says.

Passengers are often surprised by how much wildlife inhabits the bay. "Whales will come into the bay a few times a year. On the last two Memorial Days a pod of rare black dolphins were spotted. I can't wait to see if they return again next Memorial Day," Keller says.

"Each run is different, and every day is different," Keller says. "The morning weekday runs are usually slow. People stay home until the sun comes out. All day long we get a lot of cyclists. Many of them are taking the bike loop around the bay."

Some choose to ride the Coronado to Downtown route in the afternoon because the ferry stops at the navy base on North Island to pick up commuters. Passengers get a close look at the aircraft carriers, even though they cannot disembark on the base. The ferry is escorted through the pontoons by a navy patrol boat in order ensure that no one breaches security - even photos are prohibited once you enter air station waters.

San Diego Bay is an active harbor with two commercial wharves operated by the Port of San Diego as well as numerous commercial fishing ports. Each year around 375 cargo ships pull into port to move goods and materials in and out of the bay. "Some people, especially tourists, don't realize that San Diego Bay is primarily an industrial site, and secondarily a recreational playground," Keller said. Forty-eight naval surface ships, seven submarines, four coastal patrol boats and nine navy auxiliary ships are based here. Nine cruise lines now serve San Diego harbor. More ships visit in the winter, and several are on relocation cruises, heading south from Alaska through the Panama Canal to the Caribbean. "Last month we had four cruise ships docked here, which I think must be a record," Keller said.

"I just love this job. But sometimes I feel like a 'Safety Mom' because there are 1,000 ways for people to hurt themselves out here, and our first job is the well-being of our passengers and crew. Operating these big boats safely takes real skill, especially with all the docking we do. There is only one captain and one deckhand for each trip. Coming into the Coronado Ferry Landing is tricky when the tide is going out; it pushes the ferry away from the dock as we approach."

TAXIS ON THE WATER

With more than 60 waterfront restaurants, San Diego Bay provides some of the world's most picturesque dining options. The Port of San Diego, in its "Big Bay" promotion, encourages locals and visitors alike to "Dock and Dine" and leave the traffic and parking hassles behind. You don't have to be a boat owner to arrive at one of these bayside restaurants in style. Diners can summon a water taxi to escort them to the restaurant of their choice, as far south as Loews Coronado Bay Resort's Azzura Point or north to restaurant row on Shelter Island.

Every Harbor Excursion captain is cross-trained on all the company's vessels, so Keller also pilots the water taxi. "At $6 a trip, the water taxi is the best bay bargain," she recommends. "You're closer to the water and it's more intimate. It's my favorite way cross the bay.

"People don't realize that Horton Plaza is just three blocks from our stop at the San Diego Marriott. It's a fun way to get downtown for people in Coronado."

And by the time the Padres start playing next spring, the Fifth Avenue dock by the Convention Center will have been renovated. "We were operating in a pretty make-shift location last season. It's really a popular service, and it will be even better next year with a new dock and ramp," she says.

CRUISING ON THE BAY

When San Diegans travel to places like Boston or New York, they often go on dinner cruises to see the sights - but they might not think of going on a cruise here in their own home town. Rebecca Milkey, director of marketing for Hornblower Cruises and Events encourages San Diegans to get out and enjoy the spectacular harbor views as a treat for themselves. Milkey says Hornblower's most popular offering is their three-hour sunset dinner cruises offered daily. "It's a wonderful way to get out on the bay."

Hornblower's fleet of seven yachts includes some of the largest in Southern California. "That means our dining rooms are really roomy," Milkey says, noting that since they don't have "traditional" cruise-ship seating, people can opt to sit at a table all to themselves. "And our dance floors are really big, too. People love to dance on the water."

Hornblower has an "open wheelhouse" policy, so guests can wander up to the wheelhouse and visit with the captain.

People really love passing under the San Diego-Coronado Bay Bridge, Milkey said. And, she says winter is a great time for cruising the bay, especially during the holiday season. The 34th Annual Parade of Lights is a distinctly Californian tradition where boats decorated for the holidays sail from the east end of Shelter Island to the downtown waterfront. On Dec. 11 and 18, Hornblower dinner cruises will leave a half hour earlier so passengers can observe the parade as part of their cruise. For those who don't want to cook a big holiday meal for the family, a Thanksgiving or Christmas cruise for all the relatives could be just the thing. "We serve a traditional holiday buffet dinner on these occasions," Milkey said. "And there's no better seat for the New Year's Eve fireworks than out on the bay."

DO IT YOURSELF BOATING

If you want to get out on the water under your own steam, you can always rent a boat from one of the marinas. Seaforth Boat Rentals has one location by the Boathouse 1887 restaurant across from the Hotel del Coronado on Glorietta Bay, and another downtown in the Marriott marina. With 50 boats available in Coronado alone, Seaforth has a boat for any group size and skill level.

"We like to see that you've had experience if you're taking out a sailboat or large power boat," says Ian Young of Seaforth. "We can provide a refresher course for the first fifteen to thirty minutes of your rental time. We give you a detailed map explaining the speed limits and boundaries and we will show you how to handle the boat before you go out. Plus, if you don't know how to sail, or you don't want to operate your powerboat, we have skippers who can take you out."

Seaforth also rents smaller personal watercraft like waterski boats, jet-skis and kayaks. And for the really adventurous, kite-boarding might be the ticket. This new sport uses a kite instead of a boat to pull you along the water on a board. Calikites of Coronado teache the technique right in San Diego Bay.

VENEZIA IN SOUTH BAY

For a real change of pace, treat yourself to a trip to Loews Coronado Bay Resort and take a ride in a gondola through the canals of the Coronado Cays. The experience can be enhanced by a strumming mandolin player at the back of the authentic gondola as you and your partner sip champagne and watch the sun set. Sean Jamieson of The Gondola Company says some San Diegans are reluctant to go out on the bay in the winter and they shouldn't be. "We have some of the most beautiful sunsets in winter, and we provide the passengers with blankets to keep warm." And if you can't get away during the holidays, a gift certificate for Valentine's Day or other special occasion makes a very romantic present.

A TASTE OF THE YACHTING LIFE

Chartering a sumptuous, high-end boat can help make a special occasion even more extraordinary.

Whether you're planning a party for four or 400, holding your event on a luxurious sailing or motor yacht can be a spectacular and fun way to go. Boats of all sizes are available for charter from marinas around the bay. Coronadan Bruno Schwarz operates the Aolani, a luxury catamaran that is available for harbor cruises, overnight trips (four staterooms are located downstairs off the main salon) and special events such as weddings and corporate team building. This elegant new, high-performance 58-foot sailing cat can handle a party of up to 49 guests.

The nice thing about catamarans, says Schwarz, is that they offer greater stability in rough water than other sailboats. "And our wider girth allows us to be more child-friendly than smaller sailboats; the kids have lots of space to explore on board."

The Aolani crew can provide meals, and also works with many bayside restaurants that bring their catered food aboard. "Recently we had a party catered by Il Fornaio. We pulled up to the dock in front of Peohe's and the Il Fornaio staff wheeled hot food down to the boat in chafing dishes. The guests felt really pampered," Schwarz said.

Another company operating out of Coronado is Charter Connection which specializes in private fine-dining yacht charters. The fleet includes the luxurious Chere Amie, based out of Coronado, and the Belle Amie in San Diego. A benefit of private charters is that you can pick the time your cruise leaves, rather than leave on a pre-set schedule. "Our specialty is incredibly good food," says Pamela Terrebone, vice president of Charter Connection. "Our Executive Chef, Rick Huffman, is one of the most talented chefs in Southern California. He was invited on to the Culinary Olympic Team."

Many other companies charter luxury sail and power yachts out of marinas downtown or on Shelter and Harbor Island. They can arrange to meet you at the most convenient dock on the bay. The Jada, a 71-foot classic yacht based out of the Marriott marina downtown and able to hold up to 43 people, is operated by Royal Yacht Charters which also has the 80-foot Jada Royale motor yacht for parties up to 49.

A WORLD-CLASS COMMUTE

The San Diego skyline emerges at daybreak as a handful of Coronado commuters gather at the Ferry Landing - some on foot with coffee and briefcases in hand, others with their bikes and iPods. This ferry will leave at 7:15, but one has already ferried passengers to town well before sunrise. Who are these people who ply the bay in the wee hours to get to work?

Five years ago, John Hofmockel reached the end of his patience with commuting from Tierrasanta to his office at SANDAG in downtown San Diego. Tired of sitting in traffic or negotiating bus connections, he and his family moved to Coronado, and one of the main reasons was so he could ride the ferry to work every day.

"I don't have to deal with parking. I ride my bike to the Ferry Landing, take the fifteen-minute ride and then pedal up to Fourth Avenue. So I get a little exercise too," he says.

Oh, and did he mention that it's free?

The first four morning ferry runs are free both directions, with regular prices starting at 9 a.m. All early morning passengers, commuters for the most part, receive a voucher valid for an afternoon return trip.

Hofmockel likes to simply watch the scenery on his peaceful rides across the bay. In addition to enjoying the mellow natural surroundings on his daily bay commutes, he sometimes reads the sports pages or chats with fellow commuters; a few dozen regulars share his commute, and about a third of them use their bikes.

The commuter service began in 1993 when the city of Coronado was searching for alternative ways for people to get to the island - especially to the naval facilities - while the San Diego-Coronado Bay Bridge was being resurfaced. The city subsidized the early morning ferry runs.

Gail Bridges, the aptly named project manager in the engineering department for the city, says the early morning ferry routes were immediately popular.

"We struggled to keep it funded so we could continue to offer it free for the commuters," Bridges said. Through special legislation from the Transportation Development Act, the city has since secured Federal funds to continue the service as long as ridership figures stay strong, which they have. "The number of riders doubled after 9-11. It was a hassle getting to the North Island Naval Air Station once increased security measures were instituted," she said. The Navy promotes the service heavily because the early morning shift on the base starts at 6 a.m. Most of the ferry commuters come from San Diego for those first morning runs.

"We're now promoting a car-sharing service called 'Flex Car,"' Bridges says. Someone from Coronado can take the ferry and then pick up a car they've reserved from the lot at the train station and go on the next leg of their trip. "Commuters to and from Coronado really have alternatives to driving the bridge if they do their research. I've heard of people living in Santee who take the trolley to the ferry and work at the Naval Air Station on North Island. Isn't that incredible?"

FERRY FACTS

The ferry leaves Broadway Pier on the hour from 9 am until 9 pm (there is an additional 10 pm ferry on Friday and Saturday nights). Likewise, the ferry departs the Coronado Ferry Landing on the half hour from 9:30 am until 9:30 pm (10:30 on Friday and Saturdays). A round trip is $5.50; $6.50 with bike.

Parking is free at the Ferry Landing. On the San Diego side, parking is available at lots on Harbor Drive or by the Santa Fe train station, and you'll pay a maximum $12 for a full day.

ONCE IN CORONADO

• The 904 Coronado Shuttle can take you down Orange Avenue to the Hotel del Coronado and beyond to the new City Hall and Recreation Center on Strand Way. The bus leaves on the half hour from First Street and B Avenue in front of the Ferry Landing.

• It's a 30 to 50 minute walk from the bay side of the island to the beach and the Hotel del Coronado. Walk and shop your way up Orange Avenue or turn left off the ferry ramp and follow the path that traces the bay to Tidelands Park, under the Coronado Bridge and past the Coronado Golf Course and the stately homes along Glorietta Boulevard.

• Rent a bike, surrey, tandem or moped from Wheel Fun at the Coronado Island Marriott Resort, or from Bikes and Beyond at the Ferry Landing. Bikes and surreys can also be rented at the Downtown Marriott Wheel Fun location.