The Pro-Line 18 Flats 2011 vs Pro-Line 29 Grand Sport 2007 comparison sits squarely in the category of decisions where specs alone won't tell the whole story — intended use, storage, and long-term ownership costs all factor in.
Size is the most obvious dividing line here. The Pro-Line 29 Grand Sport 2007 measures 29,0 feet overall (2007), giving it roughly 10,7 additional feet of deck space compared to the Pro-Line 18 Flats 2011 at 18,3 feet (2011). Weight tells a clearer story for trailering families: the Pro-Line 18 Flats 2011 tips the scales at 1 548 lbs — 917 lbs more than the Pro-Line 29 Grand Sport 2007 at 631 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 500 hp, the Pro-Line 29 Grand Sport 2007 has a 385-hp advantage over the Pro-Line 18 Flats 2011's 115-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Both carry nearly identical fuel loads — 27 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 Pro-Line 29 Grand Sport 2007 is rated for 8 passengers, while the Pro-Line 18 Flats 2011 caps at 5. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Pro-Line 29 Grand Sport 2007 could be the deciding factor.
Bottom line: Choose the Pro-Line 29 Grand Sport 2007 if your priority is putting more people on the water — it handles 8 passengers and at 29,0 ft it has the deck room to back that rating up comfortably. The Pro-Line 18 Flats 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 5 that costs less to run day-to-day.