When two boats share the same hull type — in this case both the Larson 1850 LX 2010 and the Larson SEi 180 Ski Fish O/B 2006 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 1850 LX 2010 at 18,8 ft versus Larson SEi 180 Ski Fish O/B 2006 at 17,0 ft. Weight tells a clearer story for trailering families: the Larson 1850 LX 2010 tips the scales at 2 375 lbs — 2 358 lbs more than the Larson SEi 180 Ski Fish O/B 2006 at 17 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 1850 LX 2010 has a 40-hp advantage over the Larson SEi 180 Ski Fish O/B 2006's 150-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Both carry nearly identical fuel loads — 23 gal and 23 gal — so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Larson 1850 LX 2010 is rated for 7 passengers, while the Larson SEi 180 Ski Fish O/B 2006 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Larson 1850 LX 2010 could be the deciding factor.
Bottom line: Choose the Larson 1850 LX 2010 if your priority is putting more people on the water — it handles 7 passengers and at 18,8 ft it has the deck room to back that rating up comfortably. The Larson SEi 180 Ski Fish O/B 2006 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.