Both the Mariah R18.9 2010 and the Mariah R26 2011 are modified-V designs, the first built in fibreglass and the second in aluminium, so the buying decision usually comes down to a handful of practical questions: how many people are you putting on the water, how far do you trailer, and what does your tow vehicle weigh?
Size is the most obvious dividing line here. The Mariah R26 2011 measures 26,4 feet overall (2011), giving it roughly 8,1 additional feet of deck space compared to the Mariah R18.9 2010 at 18,3 feet (2010). Weight tells a clearer story for trailering families: the Mariah R26 2011 tips the scales at 5 000 lbs - 1 700 lbs less than the Mariah R18.9 2010 at 3 300 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.
The power gap is worth calling out. Rated to 425 hp, the Mariah R26 2011 has a 200-hp advantage over the Mariah R18.9 2010's 225-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Mariah R26 2011 carries 75 gallons versus 22 gallons in the Mariah R18.9 2010. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
Both boats are rated for 8 passengers - a good fit for a family of four or five plus guests. Comfort at capacity is another matter; the longer hull typically means more seat options and better weight distribution.
Bottom line: The Mariah R26 2011 at 26,4 ft is the right call if deck space, comfort, and entertaining are top of your list. The Mariah R18.9 2010 at 18,3 ft wins on trailering ease, likely lower purchase price, and simpler docking - a solid choice for a buyer who wants more boat for less money.