Think of the beach in summertime: warm sand between your toes, the salty caress of a gentle wave, and a bite of fish so fresh that your head clears from the simple joy of its salty flavor.

Evoking that memory is the singular goal of Tackle Box, the new urban “lobster shack” now open on M Street in Georgetown. The fish on offer are not New England’s typical haddock and cod, but rainbow trout and bluefish that pack as much briny punch and have the advantage of environmental sustainability.

Tackle Box has some kinks to work out before balancing speedy service with attentive presentation, but it has an excellent role model right next door in Hook, which boasts the same owners. In a city where local seafood is hard to find without white tablecloths and a library-like ambience, the promise of a beach meal on the cheap is irresistible.

A lobster lover has two choices at Tackle Box. The lobster roll, an ample size for $19, is served with addictively spicy skinny fries and a house-made mayonnaise that adds a vinegary tang to its creamy base.

For the traditional steamed crustacean, you need to carry out a “lobster pot,” which offers a dizzying array of tastes and a dizzying price tag of $40 per person. In addition to the one-and-a-quarter-pound Maine lobster, caught using environmentally friendly sustainable techniques, the pots contain a half-dozen mussels, quahog clams, corn, chorizo and potatoes.

After polishing off one lobster pot with a companion, I was left with a full stomach but an underwhelmed palate.

Though the take-home concept is undoubtedly appealing, good shellfish requires a chef who can blend a savory broth to match its complex textures, not a take-home mélange of white wine and water.

Tackle Box solves that seasoning dilemma with a roster of sauces that come with both the lobster pot and the cutely named Maine Meal entree, which pairs one sustainable fish with two side dishes. The fragrant, earthy basil-walnut pesto and spicy, light creamy marinara are good enough to buy by the bottle, but only a silver dollar-sized portion comes with each meal, so make sure to ask for extra.

The fish in each $13 Maine Meal comes grilled or fried in a light breadcrumb batter. My eyes lit up seeing bay scallops and shrimp on the faux-chalkboard menu, but darkened when I realized neither was available grilled.

Healthier eaters are advised to go with grilled tilapia or bluefish, the latter emerald-flecked from a subtle herb marinade that balances its oily notes. Still, Tackle Box would win more converts by cooking all of its daily catches in either method.

Yet there may be a reason why fewer fish are available grilled. Cooking each dish to order on an industrial heat source can lead to uneven work when juggling many orders at once, as I discovered taking a stomach-turning bite of grilled calamari that was congealed and raw in the middle.

Among the side orders, the grilled asparagus snaps entice with a zing of herbs and the braised collard greens are a revelation, bursting with rich smoke and studded with tender pieces of meat. As refreshing as the normal-sized portions are, both the regular and sweet-potato fries will tempt you to make it a double.

Alongside the lobster pots and Maine Meals are some unabashedly artery-clogging staples reminiscent of the beachside spots that inspired Tackle Box: fried clams with tartar sauce, grilled or fried oysters, and a small mountain of peel-and-eat shrimp that make a stellar late-night snack covered in the kitchen’s homemade spice mix.

The desserts are hearty favorites that match the dining room’s all-American vibe. There is a dense fudge brownie, and a blueberry pie with a crust redolent of cinnamon and shortening, the sort you’d expect Grandma to have cooling on her windowsill.

The seating at Tackle Box is casual, offering comfortable benches outside the front door or long, rustic wooden picnic tables. Servers and managers are universally pleasant, even when long lines during prime time test the quick-and-easy shack concept.

The décor is meant to be low-key and laid-back. The right design elements are all in place, from the colorful antiqued buoys that line the rafters to the shingled indoor roof.

All in all, Tackle Box is a welcome addition to a strip dominated by snobby-chic perennials such as Bistro Francais and the ethnic fare of Miss Saigon and Moby Dick. But Hook rises above other seafood restaurants precisely because it avoids the paint-by-numbers approach. This younger sibling, clearly in its budding stages after being open little more than week, has to ward against style over substance.

The New England that Tackle Box harkens back to isn’t the one of waves and sand. It’s the one of J. Crew catalogs.