When two boats share the same hull type — in this case both the Nautica RIB 17 & 18 Express 2011 and the Nautica RIB 28 Catamaran 2011 are inflatable rigid designs with fiberglass 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?
Both boats share a closely matched power ceiling — 230 hp for the Nautica RIB 17 & 18 Express 2011 and 230 hp for the Nautica RIB 28 Catamaran 2011. Real-world performance will come down more to which motor is actually bolted on, its load at the time, and whether it's a 4-stroke or 2-stroke setup. Fuel capacity breaks the other way: the Nautica RIB 17 & 18 Express 2011 carries 48 gallons versus 1 gallons in the Nautica RIB 28 Catamaran 2011. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Nautica RIB 28 Catamaran 2011 is rated for 25 passengers, while the Nautica RIB 17 & 18 Express 2011 caps at 11. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Nautica RIB 28 Catamaran 2011 could be the deciding factor.
Bottom line: Choose the Nautica RIB 28 Catamaran 2011 if your priority is putting more people on the water — it handles 25 passengers and at 28,0 ft it has the deck room to back that rating up comfortably. The Nautica RIB 17 & 18 Express 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 11 that costs less to run day-to-day.