When you’ve spent years in the boating community, it’s easy to fit new models neatly into boxes. That boat’s an express. This one’s a pilothouse. The one over there is a sedan, motoryacht, runabout, what have you. Such nice labels clearly define what a boat is, what it has to offer and how you should use it.

Then along comes a new design that really shakes things up.

When Cruisers Yachts of Oconto, Wisconsin, first announced its plans for a new 48-footer, the boat was poised to take its place in the 57-year-old boatbuilder’s Sports Coupe series. These yachts, an evolution of the express design concept, boast the lines, profiles and performance of express boats while reducing canvas, adding amenities and providing enhanced topside protection against inclement weather and sea conditions.

That makes sense. Cruisers Yachts has long been celebrated as an express manufacturer, and its newer coupes are the next logical steps in product development. But then word got out that the 48 Cantius Sports Coupe was more than a next step. It was a leap.

I traveled to Oconto on a warm, rainy September day to check out the just-launched prototype in person. Walking across the parking lot at the city’s harbor with Jon Viestenz, Cruisers Yachts’ product manager, I could see several of the company’s yachts lined up at the dock. And I had a startling “which of these things is not like the others” moment. Viestenz noticed.

“She’s not like any of our other boats, is she?” he asked, grinning.

I’ll say. Ahead of me sat a sleek contemporary yacht that, at a glance, appeared to be express in style. But then I saw the megayacht-inspired dual-entrance cockpit and post-glazed portlights, the large cockpit patio door and all the glass. So, so much glass.

“When we worked with (director of engineering) Tony Martens on the future of our product, we knew that our core market would still be 30- to 55 feet,” Viestenz explained. “We also realized that we have two customers. Up to 38 feet, they’re traditional express customers. But above 40 feet, we’re seeing customers who want air-conditioning, heat, better visibility and amenities in indoor and outdoor living spaces that are just a door handle away.”

We ducked beneath the hardtop to get out of the soaking rain. I made a quick note of the U-shaped cockpit seating, adjustable teak table and optional port-side electric grill as Viestenz slid open the 97- by 78-inch patio door. And in that instant, the 48’s upper salon became part of the cockpit — without the rain.

The upper salon is exactly that. It features lounge seating, a large dining table, a wet bar with sink and bottle storage and an optional 32-inch television that descends into the counter when not in use. With the tri-slide patio door open, the living space blends seamlessly into the cockpit, which you also can equip with a refrigerator and ice maker.

Not only can several adults relax comfortably here regardless of weather, this area also serves as the 48’s pilothouse. The standard double helm seat faces a state-of-the art navigational center that’s a far cry from the enormous, cumbersome dashboards of old. But the real news here is the visibility: With the big patio door and 165 square feet of enclosed glass, the 48 Cantius provides unobstructed 360-degree views. It also has a 71- by 71-inch power-actuated sunroof with manual sun shade and a walk-through windshield with air vent.

The twin themes of openness and light carry through the yacht’s interior. Aboard a traditional express-style yacht, you’d slide open a companionway hatch and step down into an interior illuminated by small portlights, occasional hatches and headliner lights. On the 48 Cantius, those amidships stairs are there, but they stand in a wide-open interior space and descend in a flood of natural light through the open dash.

From the lower salon, you have the boating equivalent of a cathedral ceiling in a split-level home. And as you move forward, you have an unobstructed view back to the upper salon and even out to the cockpit lounge. If you don’t like feeling cooped up down below, you’re going to love this.

“There’s no disconnect,” Viestenz observed. “You can talk to anyone, see and hear kids anywhere — there’s no ‘belowdecks’ anymore.”

Marveling at the whopping 7-foot headroom, I sat on the lower salon’s L-shaped sofa, which features double incliners and faces two square dinette tables. While our test boat featured the available wenge wood interior, cherry is standard; either way, the warm tones and contemporary interior design create an appealing, homelike environment. A 32-inch television is available, but quite frankly, I’d be happy on this comfortable sofa with a book, listening to the rain pattering on the windows high overhead.

The port-side galley provides an upright stainless-steel refrigerator/freezer, microwave/convection oven, electric stove, double sink and lots of storage. Forward is the guest accommodations, incorporating a queen island berth with drawers underneath, full-length cedar closets, a private shower compartment and private access to the day head, which also offers public companionway access.

The full-beam master stateroom is located aft. It offers impressive headroom — 7 feet at the entrance and 6 feet, 6 inches at the foot of the bed — as well as an island queen berth with therapeutic foam mattress, a private head compartment with separate shower stall, a dedicated sink and vanity area illuminated by a large post-glazed portlight, and every imaginable type of storage space, from full-length cedar closets to a built-in dresser. A washer/dryer combo unit is available for the port-side closet.

With its open design and generous accommodations, the 48 Cantius feels like she should be 10 feet longer than she is. Yet a couple can easily manage her, and she takes quite a bit of the hassle out of cruising. To start, you won’t have to be a contortionist to manage routine maintenance and service tasks in the engine room, which has 5 feet, 4 inches of headroom, a large hatch that allows plenty of natural light and a well-organized layout.

Moving around the boat when casting off the docklines or returning to port will be easier and safer with the walk-through windshield, 14-inch sidedecks and dual-entry cockpit. You definitely won’t have to wrangle canvas; the only removable coverings are the all-weather slip-covers for the aft seating and foredeck chaise-lounge cushions.

And you can control your onboard climate with four heating and air-conditioning units — 64,000 BTU all together — powered by a standard 15.5-kilowatt generator. The ability to heat all enclosed living spaces is a significant benefit for Great Lakes boaters, who can then extend their boating season well into the shoulder months.

“We researched the domestic and international markets for more than two and a half years, and we couldn’t find a boat in this class that could complete on all levels,” Viestenz said. “You could maybe cherry-pick a few features, but not all of them, and not standard: the full-beam master, the open concept, the dual salons, the patio door, the dual cockpit entrances, the engine room, the generator, the IPS.”

Indeed, a shining star in the 48’s standard-features list is its power package: twin Volvo Penta IPS engines with joystick control. This revolutionary propulsion system dramatically increases fuel efficiency and offers better top speeds as well as faster acceleration. It also gives the boat a tighter turning radius and gives the captain greater maneuverability in close quarters.

Despite the downpour and thickening fog, we decided to take the new 48 for a quick spin on Green Bay. While mechanical engineer Todd Trepanier fired up the IPS 600s, I took a peek at the huge transom storage compartment, with its interior lights, fender racks and tidy hooks for properly coiled lines. Nice touch.

Engaging the joystick’s docking mode, I crabbed the boat sideways from her dock. We slipped smoothly forward, pivoted with a twist of the wrist and then motored down the final stretch of the Oconto River toward the harbor entrance.

I put the throttles in gear to disengage the joystick, perched against the helm’s flip-up bolster and scanned the waters ahead. Or, rather, I tried to. Thanks to the warm, windless day and cool surface temperatures, visibility had dropped to a quarter-mile. So instead of seeking the 48’s top speed of 37 miles per hour, or even her prime cruising speed of 30 miles per hour, we stayed in the low to mid-20s and kept our eyes peeled for fishermen and barely submerged driftwood.

Although I’ve driven a variety of boats with IPS engines in recent years, I haven’t quite gotten over the superior performance and handling they offer. The 48 Cantius surged onto plane quickly and effortlessly, gracefully dipping her rail and curving through the flat-calm lake with each turn of the helm. I could’ve done this all day.

With the new 48 Cantius, Cruisers Yachts has done more than build a new boat for the 2011 model year. It’s found the sweet spot where form meets function, and in the process, it’s carving a new niche in an industry eager for something exciting to talk about.

“We hope the open concept is going to change how people use their boats,” Viestenz said as he gave me a quick tour of Cruisers Yachts new 15,000-square-foot factory showroom. Here, dealers can bring customers to view any model in the current lineup and treat the space, from offices to inventory, as their own.

Viestenz’s enthusiasm was infectious. It’s heartening to see a boatbuilder rise to meet the many challenges of the last couple of years, whether it’s providing a much-needed sales resource to dealers — or inspiring boaters with an innovative design that just won’t fit into a tidy box.