When two boats share the same hull type — in this case both the Zodiac Cadet RIB 310 2013 and the Zodiac Pro Open 850 2010 are inflatable 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 Zodiac Pro Open 850 2010 measures 27,9 feet overall (2010), giving it roughly 17,8 additional feet of deck space compared to the Zodiac Cadet RIB 310 2013 at 10,2 feet (2013). Weight tells a clearer story for trailering families: the Zodiac Pro Open 850 2010 tips the scales at 3 307 lbs — 3 115 lbs less than the Zodiac Cadet RIB 310 2013 at 192 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 350 hp, the Zodiac Pro Open 850 2010 has a 330-hp advantage over the Zodiac Cadet RIB 310 2013's 20-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 Zodiac Pro Open 850 2010 is rated for 8 passengers, while the Zodiac Cadet RIB 310 2013 caps at 5. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Zodiac Pro Open 850 2010 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Zodiac Pro Open 850 2010 comes in at 9 lbs per hp versus 10 lbs per hp for the Zodiac Cadet RIB 310 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 Zodiac Pro Open 850 2010 has a documented top speed of 57 mph. Speed data wasn't available for the other model.
The Zodiac Cadet RIB 310 2013 is an inflatable design — lighter, easier to store, and quicker to launch from a beach or dock without a slipway. The Zodiac Pro Open 850 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 Zodiac Pro Open 850 2010 if your priority is putting more people on the water — it handles 8 passengers and at 27,9 ft it has the deck room to back that rating up comfortably. The Zodiac Cadet RIB 310 2013 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 5 that costs less to run day-to-day.