The Harris Grand Mariner 250 offers a classic example of the upscale furniture found aboard today’s luxury pontoons. Couchlike seating features plump pillow tops, with diamond-pattern lumbar regions and generously bolstered support at the bottom cushion’s edge. Below, more buttery vinyl dresses the roto-molded seat bases. Gutters to drain away water and two-part hinges to allow seats to pivot fully out of the way are standard issue. It’s a theme followed throughout the interior, from the twin forward lounges with their forward-facing seat backs and flip-down armrests, to the L-shaped aft bench with its shared pivoting backrest and adjacent sun pad. Only a portside entertainment center breaks up this loungefest, complete with granite-style countertop, covered sink and trash bin, and a flip-up table that makes use of the space normally lost to a side gate.