When two boats share the same hull type — in this case both the Achilles RS-156 2010 and the Achilles SU-18 Commercial 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?
On paper these two are close siblings in the size department — Achilles RS-156 2010 at 15,5 ft versus Achilles SU-18 Commercial 2013 at 18,0 ft. Weight tells a clearer story for trailering families: the Achilles SU-18 Commercial 2013 tips the scales at 433 lbs — 281 lbs less than the Achilles RS-156 2010 at 152 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 Commercial 2013 tops out at 90 hp. Engine specs for the Achilles RS-156 2010 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 RS-156 2010 is rated for 12 passengers, while the Achilles SU-18 Commercial 2013 caps at 11. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Achilles RS-156 2010 could be the deciding factor.
The Achilles SU-18 Commercial 2013 is an inflatable design — lighter, easier to store, and quicker to launch from a beach or dock without a slipway. The Achilles RS-156 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 RS-156 2010 if your priority is putting more people on the water — it handles 12 passengers and at 15,5 ft it has the deck room to back that rating up comfortably. The Achilles SU-18 Commercial 2013 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 11 that costs less to run day-to-day.