Matching a inflatable rigid Achilles HB-280DX 2011 against a inflatable non rigid Achilles SU-18 2011 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 2011 measures 18,0 feet overall (2011), giving it roughly 8,8 additional feet of deck space compared to the Achilles HB-280DX 2011 at 9,2 feet (2011). Weight tells a clearer story for trailering families: the Achilles HB-280DX 2011 tips the scales at 148 lbs — 104 lbs more than the Achilles SU-18 2011 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 power gap is worth calling out. Rated to 90 hp, the Achilles SU-18 2011 has a 75-hp advantage over the Achilles HB-280DX 2011's 15-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 Achilles SU-18 2011 is rated for 11 passengers, while the Achilles HB-280DX 2011 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 2011 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Achilles SU-18 2011 comes in at 1 lbs per hp versus 10 lbs per hp for the Achilles HB-280DX 2011. The lower the ratio the more explosive the acceleration — meaningful on a short RIB where bursts of speed, quick planing, and agility in surf or tight waterways define the experience.
Both are inflatable designs, which means they pack down for compact storage, can be carried in a bag, and are dramatically lighter than equivalent rigid hulls. The trade-off is setup time and the need to monitor tube pressure regularly. Tube diameter differs: 17 in. (43 cm) on the Achilles HB-280DX 2011 vs 24 in. (60 cm) on the Achilles SU-18 2011 — larger tubes generally mean more buoyancy and a drier, more stable ride.
Bottom line: Choose the Achilles SU-18 2011 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 HB-280DX 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.