Both the Sun Tracker Party Barge 20 2011 and the Sun Tracker Party Barge 21 2010 are pontoon designs, both built 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?
On paper these two are close siblings in the size department - Sun Tracker Party Barge 20 2011 at 21,7 ft versus Sun Tracker Party Barge 21 2010 at 21,0 ft. Weight tells a clearer story for trailering families: the Sun Tracker Party Barge 21 2010 tips the scales at 1 873 lbs - 258 lbs less than the Sun Tracker Party Barge 20 2011 at 1 615 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 115 hp, the Sun Tracker Party Barge 20 2011 has a 25-hp advantage over the Sun Tracker Party Barge 21 2010's 90-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Both carry nearly identical fuel loads - 42 gal and 42 gal - so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Sun Tracker Party Barge 21 2010 is rated for 11 passengers, while the Sun Tracker Party Barge 20 2011 caps at 10. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Sun Tracker Party Barge 21 2010 could be the deciding factor.
Bottom line: Choose the Sun Tracker Party Barge 21 2010 if your priority is putting more people on the water - it handles 11 passengers and at 21,0 ft it has the deck room to back that rating up comfortably. The Sun Tracker Party Barge 20 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 10 that costs less to run day-to-day.