When two boats share the same hull type — in this case both the Sweetwater SW 1780 F3 2008 and the Sweetwater SW 2180 RE3 2009 are pontoon designs with aluminum 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?
Size is the most obvious dividing line here. The Sweetwater SW 2180 RE3 2009 measures 21,0 feet overall (2009), giving it roughly 4,0 additional feet of deck space compared to the Sweetwater SW 1780 F3 2008 at 17,0 feet (2008). Weight tells a clearer story for trailering families: the Sweetwater SW 2180 RE3 2009 tips the scales at 2 187 lbs — 884 lbs less than the Sweetwater SW 1780 F3 2008 at 1 303 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 Sweetwater SW 2180 RE3 2009 has a 30-hp advantage over the Sweetwater SW 1780 F3 2008's 60-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Both carry nearly identical fuel loads — 24 gal and 24 gal — so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Sweetwater SW 2180 RE3 2009 is rated for 10 passengers, while the Sweetwater SW 1780 F3 2008 caps at 8. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Sweetwater SW 2180 RE3 2009 could be the deciding factor.
Bottom line: Choose the Sweetwater SW 2180 RE3 2009 if your priority is putting more people on the water — it handles 10 passengers and at 21,0 ft it has the deck room to back that rating up comfortably. The Sweetwater SW 1780 F3 2008 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 8 that costs less to run day-to-day.