SEQUOIA -- Washington Harbour, 3000 K St. NW. 944-4200. Open: Sunday through Thursday 11:30 a.m. to midnight, Friday and Saturday 11:30 a.m. to 1 a.m. All major credit cards. Reservations suggested. Separate non-smoking section. Prices: appetizers $4.95 to $7.95, entrees $6.95 to $21.95. Full dinner with drinks, tax and tip about $30 to $40 per person.

THE FLAGSHIP OF WASHINGTON Harbour has set sail again, rechristened Sequoia. And instead of the three-ring circus that was Potomac, this time it's passing itself off as the Love Boat.

Sequoia is romantic rather than hyperactive. Its interior looks smaller now that the balcony has been turned into a bar and the first floor has been revised to include such practicalities as kitchen space and restrooms (albeit unisex). No more ceiling encrusted with glass jewels and chandeliers heavy enough to sink Venice. Now the dining room is sedate, its tone set by wooden chairs that look handcrafted and match the floor. The main decoration is the terrace, viewed through the windows and reflected in mirrors that seem to turn it into a Japanese watercolor painting.

That terrace, with hundreds of seats, is one of the most glorious urban corners in the world. Like Potomac before it, Sequoia is poised at a serene stretch of the river that sweeps from the Kennedy Center and the Watergate to a Rosslyn whose high-rise buildings merely peek and sparkle from behind trees. Boats slither along, some of them docking at the restaurant's edge. And the sunset is unobstructed.

White canvas umbrellas shade the tables from the sun, and tiny lights in the trees illuminate the evening. The woven plastic chairs have a Parisian accent, but the young servers glow with healthy all-American good looks. They seem to be having a good time.

You too can have an awfully good time at Sequoia, though like those cheerful servers, you'll have to work at it.

Sequoia, like its Union Station sibling restaurant America, has an enormous eclectic American menu -- rather, two menus, since the indoor and outdoor ones are somewhat different. The indoor menu is more formal, with a larger array of meat and seafood entrees, and while the outdoor menu tops at $16.95, most of the hot entrees inside cost from $18.95 to $21.95. In either place, though, you could dine on an $8.95 salad or a $6.95 sandwich; and wherever you sit, you'll need to choose carefully to avoid the culinary sludge that fills most of the menu.

Even so, for me it is no contest. I'd dine outside, and I'd stop at appetizers or at most a salad. I'd leave entranced with the environment, satiated by the enormous appetizers, and neither frazzled by the excruciatingly slow kitchen nor irritated by the oversize entrees and their dreary cooking.

Instead of splurging on $20 worth of overcooked fish or greasy fat-rimmed lamb chops, I'd rather overspend on a gigantic fresh peach daiquiri or margarita. It may not have enough alcohol to make a mosquito giddy, but it is a cooling and fragrant fruity slush for just under $5.

Even among the appetizers you need to pick with care. It's a treat to find steamed soft-shell clams on a local menu, and these are fine -- a big bowlful of fresh, juicy steamers swimming in a briny broth spiked with plenty of onions and herbs. Nachos are easily a meal by themselves, mounded with guacamole, sour cream and diced tomatoes, accompanied by a de-fanged snakebite salsa. And the chili is a bracing surprise, not only because the "cup" might be considered a tureen elsewhere, but also because the meat is in tender chunks, the beans taste freshly cooked, and there is cumin and chili sizzle to the seasoning. Hot spices also add dash to seductive barbecued oysters. But guidelines don't follow a straight route here. Could this be the same kitchen that serves flaccid and soggy fried calamari, raclette of mozzarella that tastes like melted whey and Jamaican jerk-spiced chicken wings that seem ready to be seasoned rather than already done?

I can recommend the soups, some of them wholeheartedly. The gazpacho is a refreshing cold, thick mush with plenty of tomato flavor and tartness. And corn-crab chowder, though served lukewarm as every "hot" dish was on four visits, is creamy and sweetly delicate, generous with the crab meat.

This is the same kitchen that mucks up a simple sandwich and wrecks a big fat hamburger by overcooking it (after it's been compacted so you might wonder if it had been weighted down by a dictionary). I've never had a club sandwich that sounded so good (hand-sliced real turkey, peppered bacon, chatham cranberry ketchup on toasted grain bread) and tasted so bad (acceptable turkey with cold, limp and bland bacon on just two slabs of flabby, dark packaged bread). And sandwiches tend to be piled with salad fixings, both complicated and dull, as well as impossible to eat as a sandwich.

Tuna is frequently featured in salads, sandwiches and entrees; but while it may be fresh, it tastes longer-cooked than the canned stuff. Other fish are no less dried out, and bluefish roasted in a corn husk and swamped by sour cream and dill is strange. The safest choice among seafood is shrimp, for the jerk-spiced tiger prawns (no more spicy than the jerk chicken wings) and the rock shrimp on one of the pastas are left moist and firm.

Or if you want a light and refreshing meal, the pineapple half filled with fruit is a gorgeous array, and the caesar salad is excellent.

If I were mean-spirited, I'd go into greater detail about the pastas glued together in clumps; the chewy, tasteless roast chicken; the gnarled, oversweetened slabs of chicken in the oriental grilled chicken salad. Huge oval plates look so exciting when they are presented but haunt you with their volume after a few bites. The garnishes are vivid -- hair-thin green beans, broccoli ribboned with strands of red pepper, precision-diced ratatouille. But the green vegetables are all close to raw, which works better with the green beans than with the ratatouille; and those once-crisp shoestring potatoes are sullen in their coldness -- every time.

If you are not too full or dispirited for dessert, there might be a fine creamy espresso ice cream topped with berries, and even the caramel-deficient creme caramel is prettily garnished with berries. An apple tart is delicious if you scoop the tangy filling from the gummy underbaked crust. But on most of my visits the service was so slow that waiting for dessert loomed only as punishment. Even on a weekday afternoon, when barely half a dozen tables were occupied outside, we had to fetch our own silverware and share our water with tablemates who had improvidently gulped theirs.

But give me a balmy evening and a table by the water, let the sunset and the fountain entertain me, and I'd probably be willing to bring a canteen, if necessary, to enjoy Sequoia's perfect situation.