The Crestliner Backwater 1860 Tiller 2011 is a modified-V design and the Crestliner Sportfish 1850 2012 is a deep-V design, so you're likely deciding between two noticeably different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
On paper these two are close siblings in the size department - Crestliner Backwater 1860 Tiller 2011 at 18,4 ft versus Crestliner Sportfish 1850 2012 at 18,2 ft. Weight tells a clearer story for trailering families: the Crestliner Sportfish 1850 2012 tips the scales at 1 470 lbs - 640 lbs less than the Crestliner Backwater 1860 Tiller 2011 at 830 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 175 hp, the Crestliner Sportfish 1850 2012 has a 100-hp advantage over the Crestliner Backwater 1860 Tiller 2011's 75-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Crestliner Sportfish 1850 2012 is rated for 7 passengers, while the Crestliner Backwater 1860 Tiller 2011 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Crestliner Sportfish 1850 2012 could be the deciding factor.
Bottom line: Choose the Crestliner Sportfish 1850 2012 if your priority is putting more people on the water - it handles 7 passengers and at 18,2 ft it has the deck room to back that rating up comfortably. The Crestliner Backwater 1860 Tiller 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.