When two boats share the same hull type — in this case both the Larson 180 Sport I/O 2007 and the Larson LX 620 SF O/B 2012 are modified vee designs with fiberglass construction — 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?
On paper these two are close siblings in the size department — Larson 180 Sport I/O 2007 at 17,0 ft versus Larson LX 620 SF O/B 2012 at 16,2 ft. Weight tells a clearer story for trailering families: the Larson 180 Sport I/O 2007 tips the scales at 2 375 lbs — 2 260 lbs more than the Larson LX 620 SF O/B 2012 at 115 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 190 hp, the Larson 180 Sport I/O 2007 has a 100-hp advantage over the Larson LX 620 SF O/B 2012's 90-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Larson 180 Sport I/O 2007 carries 23 gallons versus 19 gallons in the Larson LX 620 SF O/B 2012. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Larson 180 Sport I/O 2007 is rated for 8 passengers, while the Larson LX 620 SF O/B 2012 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Larson 180 Sport I/O 2007 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Larson LX 620 SF O/B 2012 comes in at 1 lbs per hp versus 13 lbs per hp for the Larson 180 Sport I/O 2007. The lower the ratio the more explosive the acceleration — meaningful on a short RIB where bursts of speed, quick planing, and agility in surf or tight waterways define the experience.
Bottom line: Choose the Larson 180 Sport I/O 2007 if your priority is putting more people on the water — it handles 8 passengers and at 17,0 ft it has the deck room to back that rating up comfortably. The Larson LX 620 SF O/B 2012 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.