When two boats share the same hull type — in this case both the Alumacraft Navigator 175 Sport 2006 and the Alumacraft Navigator 185 Sport 2006 are modified vee designs with aluminum 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 — Alumacraft Navigator 175 Sport 2006 at 17,0 ft versus Alumacraft Navigator 185 Sport 2006 at 18,0 ft. Weight tells a clearer story for trailering families: the Alumacraft Navigator 175 Sport 2006 tips the scales at 1 345 lbs — 1 201 lbs more than the Alumacraft Navigator 185 Sport 2006 at 144 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.
Both boats share a closely matched power ceiling — 150 hp for the Alumacraft Navigator 175 Sport 2006 and 150 hp for the Alumacraft Navigator 185 Sport 2006. 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. Both carry nearly identical fuel loads — 4 gal and 4 gal — so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Alumacraft Navigator 185 Sport 2006 is rated for 6 passengers, while the Alumacraft Navigator 175 Sport 2006 caps at 5. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Alumacraft Navigator 185 Sport 2006 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Alumacraft Navigator 185 Sport 2006 comes in at 1 lbs per hp versus 9 lbs per hp for the Alumacraft Navigator 175 Sport 2006. 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.
Bottom line: Choose the Alumacraft Navigator 185 Sport 2006 if your priority is putting more people on the water — it handles 6 passengers and at 18,0 ft it has the deck room to back that rating up comfortably. The Alumacraft Navigator 175 Sport 2006 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 5 that costs less to run day-to-day.