Matching a pontoon Marathon Grumman Classic 2180CP 2012 against a modified vee Marathon Seneca 13 2010 means you're likely deciding between two genuinely different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
Size is the most obvious dividing line here. The Marathon Grumman Classic 2180CP 2012 measures 21,0 feet overall (2012), giving it roughly 8,0 additional feet of deck space compared to the Marathon Seneca 13 2010 at 13,0 feet (2010). Weight tells a clearer story for trailering families: the Marathon Grumman Classic 2180CP 2012 tips the scales at 1 605 lbs — 1 590 lbs more than the Marathon Seneca 13 2010 at 15 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 90 hp, the Marathon Grumman Classic 2180CP 2012 has a 75-hp advantage over the Marathon Seneca 13 2010's 15-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Marathon Grumman Classic 2180CP 2012 is rated for 9 passengers, while the Marathon Seneca 13 2010 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Marathon Grumman Classic 2180CP 2012 could be the deciding factor.
Bottom line: Choose the Marathon Grumman Classic 2180CP 2012 if your priority is putting more people on the water — it handles 9 passengers and at 21,0 ft it has the deck room to back that rating up comfortably. The Marathon Seneca 13 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.