When two boats share the same hull type — in this case both the Achilles SG-140 2010 and the Achilles SU-18 2013 are inflatable non rigid designs with inflatable construction — 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?
Size is the most obvious dividing line here. The Achilles SU-18 2013 measures 18,0 feet overall (2013), giving it roughly 4,0 additional feet of deck space compared to the Achilles SG-140 2010 at 14,0 feet (2010). Weight tells a clearer story for trailering families: the Achilles SU-18 2013 tips the scales at 433 lbs — 207 lbs less than the Achilles SG-140 2010 at 226 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 2013 has a 40-hp advantage over the Achilles SG-140 2010's 50-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 2013 is rated for 11 passengers, while the Achilles SG-140 2010 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Achilles SU-18 2013 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Achilles SG-140 2010 comes in at 5 lbs per hp versus 5 lbs per hp for the Achilles SU-18 2013. 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.
The Achilles SU-18 2013 is an inflatable design — lighter, easier to store, and quicker to launch from a beach or dock without a slipway. The Achilles SG-140 2010 is a rigid hull, which typically offers a more confident ride in chop and easier maintenance over the long term.
Bottom line: Choose the Achilles SU-18 2013 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 SG-140 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.