Matching a inflatable non rigid Achilles 140SB 2009 against a inflatable rigid Achilles SU-18 2008 means you're likely deciding between two genuinely different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
Size is the most obvious dividing line here. The Achilles SU-18 2008 measures 18,0 feet overall (2008), giving it roughly 4,0 additional feet of deck space compared to the Achilles 140SB 2009 at 14,0 feet (2009). Weight tells a clearer story for trailering families: the Achilles 140SB 2009 tips the scales at 155 lbs — 111 lbs more than the Achilles SU-18 2008 at 44 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 Achilles SU-18 2008 tops out at 90 hp. Engine specs for the Achilles 140SB 2009 aren't listed — confirm with a dealer before selecting an outboard.
For family outings this is probably the sharpest distinction between the two. The Achilles SU-18 2008 is rated for 11 passengers, while the Achilles 140SB 2009 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Achilles SU-18 2008 could be the deciding factor.
Bottom line: Choose the Achilles SU-18 2008 if your priority is putting more people on the water — it handles 11 passengers and at 18,0 ft it has the deck room to back that rating up comfortably. The Achilles 140SB 2009 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.